Sales · Weekend build
Build your own Gumroad
Sell your files and keep Gumroad’s ten percent cut for yourself. Gumroad charges $10–$50 per month — that’s $120–$600 a year — for something you can replace with focused software of your own. Here is the honest scope, the honest timeline, and the exact prompt to hand your coding agent.
Who this replacement is for
This build targets one creator selling a handful of digital products directly. The goal: publish product pages, take payment through a hosted checkout, and deliver files only to verified buyers. If you need more than that, keep paying — the point of building it yourself is owning a tool shaped exactly like your workflow, not re-implementing a venture-funded roadmap.
Same build, different logo: this v1 also replaces Lemon Squeezy, Payhip and Sellfy — they all solve the same core job.
How long it actually takes
One number would be a lie, so here are three. Each tier is a real, usable product — pick the one that matches how much of Gumroad you actually use.
| Estimate | What you get |
|---|---|
| 12 hours | product pages, checkout, signed delivery links |
| 4 days | discount codes, file versions, pay-what-you-want, receipts |
| 3 months+ | marketplace discovery, memberships, affiliates, vat handling — the part you should probably skip |
What a minimal Gumroad alternative needs
- product pages for files with price, cover, and description
- hosted checkout through one payment provider
- signed expiring download links delivered by email
- license keys generated per sale for software products
- a simple dashboard with sales, revenue, and refunds
Data model
Product, ProductFile, Sale, DownloadLink, LicenseKey
Integrations
Stripe Checkout, transactional email
Capability context
Astro, D1, R2
The guardrail
Grant file access only from verified, deduplicated payment webhooks, and sign every download URL with a short expiry tied to its sale.
Deliberate non-goals
Do not build marketplace discovery, subscriptions or memberships, affiliate programs, VAT calculation, or physical goods.
The complete build prompt
Copy this into your coding agent of choice. It is scoped for a useful v1 — journeys, screens, business rules, data model, security, tests, and acceptance scenarios included. Pick your stack:
You are building a production-ready software product named “Sellshelf”, a deliberately focused alternative to Gumroad. Build a complete, usable vertical slice—not a landing page, static mockup, or disconnected collection of components. WORKING AGREEMENT Before writing implementation code, produce a short technical plan that names the routes or pages, server actions or endpoints, data tables, important state transitions, authorization boundaries, background jobs, and external adapters. Resolve contradictions in favor of the narrow audience and non-goals below. Prefer a small, legible architecture over speculative abstraction, but do not omit persistence, validation, error handling, or tests. PRODUCT BRIEF Primary user: one creator selling a handful of digital products directly. Primary outcome: publish product pages, take payment through a hosted checkout, and deliver files only to verified buyers. Product principle: optimize the exact workflow below instead of copying the full breadth of Gumroad. A first-time user should understand what to do from the interface itself, without a tour or documentation. END-TO-END USER JOURNEYS Implement all of these flows through the real interface and persistent data layer: 1. The seller uploads a file, writes the product page, sets a price, previews the checkout flow, and publishes the product at its public URL. 2. A buyer pays through hosted checkout, receives an email with a signed expiring download link and a license key, and downloads the file. 3. The seller opens the dashboard, reviews recent sales, resends a delivery email to a buyer who lost it, and issues a refund that revokes the download link and license key. SCREENS AND INFORMATION ARCHITECTURE Build these as coherent responsive views. Each screen must specify its primary action, secondary actions, visible status, validation feedback, empty state, loading or pending state, success confirmation, and recoverable failure state. 1. Product admin: product list with published state, file uploads, price, cover image, description editor, and a license-key toggle. 2. Public product page: cover, description, price, a buy button into hosted checkout, and a clear success state after payment. 3. Delivery email and download: signed link with visible expiry, license key when applicable, remaining attempts, and a recovery path for expired links. 4. Sales dashboard: revenue totals, sale list with buyer email, product, and status, refund and resend actions, and webhook delivery health. CORE CAPABILITIES 1. product pages for files with price, cover, and description 2. hosted checkout through one payment provider 3. signed expiring download links delivered by email 4. license keys generated per sale for software products 5. a simple dashboard with sales, revenue, and refunds DETAILED BEHAVIOR AND BUSINESS RULES Treat these as server-enforced product requirements, not interface suggestions: 1. Grant download access only after a verified payment webhook commits; deduplicate provider events so one payment yields one sale and one delivery email. 2. Sign every download URL with an expiry and a sale reference, cap download attempts, and never expose bucket paths or permanent URLs. 3. Generate a unique license key per sale, verify keys against the sale record, and fail verification once the sale is refunded. 4. Store money as integer minor units, execute refunds through the payment provider, and revoke links and keys only after the provider confirms. DATA MODEL AND LIFECYCLE Design a small relational schema centered on Product, ProductFile, Sale, DownloadLink, LicenseKey. Before implementing it, document: 1. Each table’s purpose, primary key, ownership or tenant boundary, timestamps, status fields, and important attributes. 2. Foreign keys, uniqueness constraints, check constraints, indexes needed by the named screens, and transaction boundaries for multi-record changes. 3. The allowed lifecycle or state transitions, who may trigger each transition, which transitions are terminal or reversible, and what audit history must remain immutable. 4. Archive, retention, and deletion behavior, including what happens to dependent records and external files. 5. Idempotency strategy for submissions, jobs, imports, notifications, webhooks, or retries where applicable. Use migrations rather than ad-hoc schema creation. Store time instants consistently and retain named timezone context whenever local schedules or dates matter. Never rely on a counter, disabled button, or client-side check to preserve a business invariant. USERS, AUTHENTICATION, AND PERMISSIONS Implement only the roles required by the stated audience. Make the ownership and visibility model explicit before coding. Enforce authorization in every server-side query and mutation, including search, exports, attachments, live updates, and guessed URLs—not merely by hiding controls. Use secure session defaults, protect state-changing requests, and provide an understandable signed-out, expired-session, and forbidden state. Seed distinct users when multiple roles are required so permissions can be demonstrated and tested. INTERACTION AND VISUAL DIRECTION The product should feel fast, calm, focused, and credible rather than like a generic admin template. Use a clear visual hierarchy, restrained color, readable typography, generous hit targets, and consistent placement for primary actions. Start with server-rendered HTML and progressively enhance only the interactions that benefit from it. The core workflow must remain understandable if enhancement fails. Start with server-rendered Astro pages and ordinary HTML forms. Use HTMX for form submissions, partial navigation, and server-driven updates, then Alpine.js only for small local browser state. The core workflow must remain understandable if either enhancement layer fails. Design mobile layouts intentionally instead of simply stacking desktop panels. Support keyboard navigation, visible focus, semantic landmarks, explicit labels, useful page titles, reduced-motion preferences, and screen-reader announcements for asynchronous results. Never use color alone to communicate state. Destructive actions require clear scope and confirmation; safe repeated actions should be idempotent. TECHNICAL DIRECTION Build this version with the AHA stack: Astro for routing, layouts, and server-rendered pages; HTMX for interactions that benefit from HTML fragment responses; and Alpine.js for small, local interface state. Prefer Cloudflare D1 for relational persistence, R2 for object storage, Workers for server endpoints and scheduled work, Durable Objects only for coordinated real-time state, and Workflows or Queues for durable background jobs—but only when the product requirements call for them. Keep domain rules in testable server-side modules instead of route handlers or UI components. Separate persistence, external providers, and background work behind small interfaces without building a framework. Prefer ordinary HTML forms and URLs for durable navigation; use optimistic interaction only when failure can be reconciled clearly. The product brief currently identifies Astro, D1, R2 as capability context. Preserve any required native, browser-only, edge, storage, real-time, or background-processing capability through a narrow adapter appropriate to the selected framework. If the core workflow genuinely requires native or browser APIs, keep that runtime as the primary execution surface rather than simulating inaccessible capabilities or inventing an unnecessary web surface. Integrate with Stripe Checkout and transactional email. For every integration: - List required environment variables in an .env.example without real secrets. - Add a small adapter with timeouts, normalized errors, and a deterministic local fake or development path. - Verify inbound signatures and deduplicate provider events where supported. - Keep credentials server-side, encrypt long-lived provider tokens at rest, and redact secrets and sensitive payloads from logs. - Define retry, backoff, and idempotency behavior for any side effect that can be repeated. SECURITY AND PRIVACY Grant file access only from verified, deduplicated payment webhooks, and sign every download URL with a short expiry tied to its sale. Validate, normalize, and length-limit all untrusted input on the server. Escape rendered content by default, sanitize any intentionally accepted markup, rate-limit public or abuse-prone actions, and use private object storage plus short-lived authorized URLs for sensitive files. Collect the minimum personal data necessary for the named workflow. Document retention and deletion behavior. Add specific protections for the riskier surfaces in this app, such as uploads, redirects, outbound requests, email delivery, OAuth, webhooks, CSV import or export, and real-time connections. ACCEPTANCE SCENARIOS Automate these app-specific scenarios at the most appropriate level: 1. Given the same paid webhook arrives three times, exactly one sale is recorded and one delivery email is sent. 2. Given an expired download link, the buyer can request a fresh one that is issued only to the original purchase email. 3. Given a refunded sale, its download links stop working, its license key fails verification, and the dashboard shows the refund. TESTING Add focused unit tests for state transitions, authorization predicates, normalization, date or money calculations, and other risky domain rules. Add integration tests for persistence constraints and each external adapter’s success, timeout, retry, and rejection paths. Add at least one browser-level test for every end-to-end journey above, including one small-screen viewport. Tests must use isolated data and run through a documented single command. OPERATIONS AND FAILURE RECOVERY Add structured server logs with request, job, or event correlation IDs but no secrets or unnecessarily sensitive data. Make failures actionable in both the interface and logs. Background work must expose pending, succeeded, failed, and retrying states where relevant; do not silently swallow errors. Include safe database migration and rollback guidance, seed data, backup and restore notes, external-data cleanup behavior, and a basic health or diagnostic path appropriate to the stack. DELIVERABLES Ship the working application, migrations, representative seed data, tests, .env.example, and a concise README. The README must cover prerequisites, local setup, environment variables, migrations, seed and test commands, deployment, integration setup, backup and restore, security decisions, and known limitations. Seed data should exercise the happy path plus at least one empty, failed, overdue, expired, archived, or permission-restricted state relevant to the product. DEFINITION OF DONE The app is complete when a fresh developer can follow the README, create and migrate the database, run the app, sign in as each relevant role, complete every named journey using real persisted data, refresh without losing state, recover from common failures, and use the core interface on phone and desktop. All acceptance scenarios pass, permission boundaries are covered by tests, and no core screen is left as a placeholder. NON-GOALS Do not build marketplace discovery, subscriptions or memberships, affiliate programs, VAT calculation, or physical goods.
You are building a production-ready software product named “Sellshelf”, a deliberately focused alternative to Gumroad. Build a complete, usable vertical slice—not a landing page, static mockup, or disconnected collection of components. WORKING AGREEMENT Before writing implementation code, produce a short technical plan that names the routes or pages, server actions or endpoints, data tables, important state transitions, authorization boundaries, background jobs, and external adapters. Resolve contradictions in favor of the narrow audience and non-goals below. Prefer a small, legible architecture over speculative abstraction, but do not omit persistence, validation, error handling, or tests. PRODUCT BRIEF Primary user: one creator selling a handful of digital products directly. Primary outcome: publish product pages, take payment through a hosted checkout, and deliver files only to verified buyers. Product principle: optimize the exact workflow below instead of copying the full breadth of Gumroad. A first-time user should understand what to do from the interface itself, without a tour or documentation. END-TO-END USER JOURNEYS Implement all of these flows through the real interface and persistent data layer: 1. The seller uploads a file, writes the product page, sets a price, previews the checkout flow, and publishes the product at its public URL. 2. A buyer pays through hosted checkout, receives an email with a signed expiring download link and a license key, and downloads the file. 3. The seller opens the dashboard, reviews recent sales, resends a delivery email to a buyer who lost it, and issues a refund that revokes the download link and license key. SCREENS AND INFORMATION ARCHITECTURE Build these as coherent responsive views. Each screen must specify its primary action, secondary actions, visible status, validation feedback, empty state, loading or pending state, success confirmation, and recoverable failure state. 1. Product admin: product list with published state, file uploads, price, cover image, description editor, and a license-key toggle. 2. Public product page: cover, description, price, a buy button into hosted checkout, and a clear success state after payment. 3. Delivery email and download: signed link with visible expiry, license key when applicable, remaining attempts, and a recovery path for expired links. 4. Sales dashboard: revenue totals, sale list with buyer email, product, and status, refund and resend actions, and webhook delivery health. CORE CAPABILITIES 1. product pages for files with price, cover, and description 2. hosted checkout through one payment provider 3. signed expiring download links delivered by email 4. license keys generated per sale for software products 5. a simple dashboard with sales, revenue, and refunds DETAILED BEHAVIOR AND BUSINESS RULES Treat these as server-enforced product requirements, not interface suggestions: 1. Grant download access only after a verified payment webhook commits; deduplicate provider events so one payment yields one sale and one delivery email. 2. Sign every download URL with an expiry and a sale reference, cap download attempts, and never expose bucket paths or permanent URLs. 3. Generate a unique license key per sale, verify keys against the sale record, and fail verification once the sale is refunded. 4. Store money as integer minor units, execute refunds through the payment provider, and revoke links and keys only after the provider confirms. DATA MODEL AND LIFECYCLE Design a small relational schema centered on Product, ProductFile, Sale, DownloadLink, LicenseKey. Before implementing it, document: 1. Each table’s purpose, primary key, ownership or tenant boundary, timestamps, status fields, and important attributes. 2. Foreign keys, uniqueness constraints, check constraints, indexes needed by the named screens, and transaction boundaries for multi-record changes. 3. The allowed lifecycle or state transitions, who may trigger each transition, which transitions are terminal or reversible, and what audit history must remain immutable. 4. Archive, retention, and deletion behavior, including what happens to dependent records and external files. 5. Idempotency strategy for submissions, jobs, imports, notifications, webhooks, or retries where applicable. Use migrations rather than ad-hoc schema creation. Store time instants consistently and retain named timezone context whenever local schedules or dates matter. Never rely on a counter, disabled button, or client-side check to preserve a business invariant. USERS, AUTHENTICATION, AND PERMISSIONS Implement only the roles required by the stated audience. Make the ownership and visibility model explicit before coding. Enforce authorization in every server-side query and mutation, including search, exports, attachments, live updates, and guessed URLs—not merely by hiding controls. Use secure session defaults, protect state-changing requests, and provide an understandable signed-out, expired-session, and forbidden state. Seed distinct users when multiple roles are required so permissions can be demonstrated and tested. INTERACTION AND VISUAL DIRECTION The product should feel fast, calm, focused, and credible rather than like a generic admin template. Use a clear visual hierarchy, restrained color, readable typography, generous hit targets, and consistent placement for primary actions. Start with server-rendered HTML and progressively enhance only the interactions that benefit from it. The core workflow must remain understandable if enhancement fails. Render with React Server Components by default. Use Server Actions for authenticated form mutations and add Client Components only for interactions that genuinely require browser state, browser APIs, drag-and-drop, or live updates. The core workflow must remain understandable before client-side JavaScript finishes loading. Design mobile layouts intentionally instead of simply stacking desktop panels. Support keyboard navigation, visible focus, semantic landmarks, explicit labels, useful page titles, reduced-motion preferences, and screen-reader announcements for asynchronous results. Never use color alone to communicate state. Destructive actions require clear scope and confirmation; safe repeated actions should be idempotent. TECHNICAL DIRECTION Build this version with Next.js, the App Router, and TypeScript. Use Server Components by default, Server Actions for authenticated mutations, and Route Handlers for public APIs, OAuth callbacks, webhooks, feeds, uploads, and downloads. Use PostgreSQL through Drizzle ORM with versioned migrations and an isolated test database. Access S3-compatible object storage through a server-only adapter, and run slow or retryable work in a real job or workflow system instead of the request lifecycle. Keep domain rules in testable server-side modules instead of route handlers or UI components. Separate persistence, external providers, and background work behind small interfaces without building a framework. Prefer ordinary HTML forms and URLs for durable navigation; use optimistic interaction only when failure can be reconciled clearly. The product brief currently identifies Astro, D1, R2 as capability context. Preserve any required native, browser-only, edge, storage, real-time, or background-processing capability through a narrow adapter appropriate to the selected framework. If the core workflow genuinely requires native or browser APIs, keep that runtime as the primary execution surface rather than simulating inaccessible capabilities or inventing an unnecessary web surface. Integrate with Stripe Checkout and transactional email. For every integration: - List required environment variables in an .env.example without real secrets. - Add a small adapter with timeouts, normalized errors, and a deterministic local fake or development path. - Verify inbound signatures and deduplicate provider events where supported. - Keep credentials server-side, encrypt long-lived provider tokens at rest, and redact secrets and sensitive payloads from logs. - Define retry, backoff, and idempotency behavior for any side effect that can be repeated. SECURITY AND PRIVACY Grant file access only from verified, deduplicated payment webhooks, and sign every download URL with a short expiry tied to its sale. Validate, normalize, and length-limit all untrusted input on the server. Escape rendered content by default, sanitize any intentionally accepted markup, rate-limit public or abuse-prone actions, and use private object storage plus short-lived authorized URLs for sensitive files. Collect the minimum personal data necessary for the named workflow. Document retention and deletion behavior. Add specific protections for the riskier surfaces in this app, such as uploads, redirects, outbound requests, email delivery, OAuth, webhooks, CSV import or export, and real-time connections. ACCEPTANCE SCENARIOS Automate these app-specific scenarios at the most appropriate level: 1. Given the same paid webhook arrives three times, exactly one sale is recorded and one delivery email is sent. 2. Given an expired download link, the buyer can request a fresh one that is issued only to the original purchase email. 3. Given a refunded sale, its download links stop working, its license key fails verification, and the dashboard shows the refund. TESTING Add focused unit tests for state transitions, authorization predicates, normalization, date or money calculations, and other risky domain rules. Add integration tests for persistence constraints and each external adapter’s success, timeout, retry, and rejection paths. Add at least one browser-level test for every end-to-end journey above, including one small-screen viewport. Tests must use isolated data and run through a documented single command. OPERATIONS AND FAILURE RECOVERY Add structured server logs with request, job, or event correlation IDs but no secrets or unnecessarily sensitive data. Make failures actionable in both the interface and logs. Background work must expose pending, succeeded, failed, and retrying states where relevant; do not silently swallow errors. Include safe database migration and rollback guidance, seed data, backup and restore notes, external-data cleanup behavior, and a basic health or diagnostic path appropriate to the stack. DELIVERABLES Ship the working application, migrations, representative seed data, tests, .env.example, and a concise README. The README must cover prerequisites, local setup, environment variables, migrations, seed and test commands, deployment, integration setup, backup and restore, security decisions, and known limitations. Seed data should exercise the happy path plus at least one empty, failed, overdue, expired, archived, or permission-restricted state relevant to the product. DEFINITION OF DONE The app is complete when a fresh developer can follow the README, create and migrate the database, run the app, sign in as each relevant role, complete every named journey using real persisted data, refresh without losing state, recover from common failures, and use the core interface on phone and desktop. All acceptance scenarios pass, permission boundaries are covered by tests, and no core screen is left as a placeholder. NON-GOALS Do not build marketplace discovery, subscriptions or memberships, affiliate programs, VAT calculation, or physical goods.
You are building a production-ready software product named “Sellshelf”, a deliberately focused alternative to Gumroad. Build a complete, usable vertical slice—not a landing page, static mockup, or disconnected collection of components. WORKING AGREEMENT Before writing implementation code, produce a short technical plan that names the routes or pages, server actions or endpoints, data tables, important state transitions, authorization boundaries, background jobs, and external adapters. Resolve contradictions in favor of the narrow audience and non-goals below. Prefer a small, legible architecture over speculative abstraction, but do not omit persistence, validation, error handling, or tests. PRODUCT BRIEF Primary user: one creator selling a handful of digital products directly. Primary outcome: publish product pages, take payment through a hosted checkout, and deliver files only to verified buyers. Product principle: optimize the exact workflow below instead of copying the full breadth of Gumroad. A first-time user should understand what to do from the interface itself, without a tour or documentation. END-TO-END USER JOURNEYS Implement all of these flows through the real interface and persistent data layer: 1. The seller uploads a file, writes the product page, sets a price, previews the checkout flow, and publishes the product at its public URL. 2. A buyer pays through hosted checkout, receives an email with a signed expiring download link and a license key, and downloads the file. 3. The seller opens the dashboard, reviews recent sales, resends a delivery email to a buyer who lost it, and issues a refund that revokes the download link and license key. SCREENS AND INFORMATION ARCHITECTURE Build these as coherent responsive views. Each screen must specify its primary action, secondary actions, visible status, validation feedback, empty state, loading or pending state, success confirmation, and recoverable failure state. 1. Product admin: product list with published state, file uploads, price, cover image, description editor, and a license-key toggle. 2. Public product page: cover, description, price, a buy button into hosted checkout, and a clear success state after payment. 3. Delivery email and download: signed link with visible expiry, license key when applicable, remaining attempts, and a recovery path for expired links. 4. Sales dashboard: revenue totals, sale list with buyer email, product, and status, refund and resend actions, and webhook delivery health. CORE CAPABILITIES 1. product pages for files with price, cover, and description 2. hosted checkout through one payment provider 3. signed expiring download links delivered by email 4. license keys generated per sale for software products 5. a simple dashboard with sales, revenue, and refunds DETAILED BEHAVIOR AND BUSINESS RULES Treat these as server-enforced product requirements, not interface suggestions: 1. Grant download access only after a verified payment webhook commits; deduplicate provider events so one payment yields one sale and one delivery email. 2. Sign every download URL with an expiry and a sale reference, cap download attempts, and never expose bucket paths or permanent URLs. 3. Generate a unique license key per sale, verify keys against the sale record, and fail verification once the sale is refunded. 4. Store money as integer minor units, execute refunds through the payment provider, and revoke links and keys only after the provider confirms. DATA MODEL AND LIFECYCLE Design a small relational schema centered on Product, ProductFile, Sale, DownloadLink, LicenseKey. Before implementing it, document: 1. Each table’s purpose, primary key, ownership or tenant boundary, timestamps, status fields, and important attributes. 2. Foreign keys, uniqueness constraints, check constraints, indexes needed by the named screens, and transaction boundaries for multi-record changes. 3. The allowed lifecycle or state transitions, who may trigger each transition, which transitions are terminal or reversible, and what audit history must remain immutable. 4. Archive, retention, and deletion behavior, including what happens to dependent records and external files. 5. Idempotency strategy for submissions, jobs, imports, notifications, webhooks, or retries where applicable. Use migrations rather than ad-hoc schema creation. Store time instants consistently and retain named timezone context whenever local schedules or dates matter. Never rely on a counter, disabled button, or client-side check to preserve a business invariant. USERS, AUTHENTICATION, AND PERMISSIONS Implement only the roles required by the stated audience. Make the ownership and visibility model explicit before coding. Enforce authorization in every server-side query and mutation, including search, exports, attachments, live updates, and guessed URLs—not merely by hiding controls. Use secure session defaults, protect state-changing requests, and provide an understandable signed-out, expired-session, and forbidden state. Seed distinct users when multiple roles are required so permissions can be demonstrated and tested. INTERACTION AND VISUAL DIRECTION The product should feel fast, calm, focused, and credible rather than like a generic admin template. Use a clear visual hierarchy, restrained color, readable typography, generous hit targets, and consistent placement for primary actions. Start with server-rendered HTML and progressively enhance only the interactions that benefit from it. The core workflow must remain understandable if enhancement fails. Start with server-rendered Blade views and ordinary forms. Use Livewire for focused server-driven interactions and Alpine.js only for small local interface state. The core workflow must remain understandable without relying on a client-side application shell. Design mobile layouts intentionally instead of simply stacking desktop panels. Support keyboard navigation, visible focus, semantic landmarks, explicit labels, useful page titles, reduced-motion preferences, and screen-reader announcements for asynchronous results. Never use color alone to communicate state. Destructive actions require clear scope and confirmation; safe repeated actions should be idempotent. TECHNICAL DIRECTION Build this version with Laravel, PHP, Blade, Livewire, and Alpine.js. Use controllers and Blade forms for durable navigation, Livewire for focused interactions, Form Requests for validation, Policies and Gates for authorization, and small application actions or services for domain transitions. Use Eloquent with migrations, database constraints, and transactions; Laravel Storage for private S3-compatible files; queued Jobs for retryable work; the Scheduler for recurring work; and Notifications or Mail for email. Keep domain rules in testable server-side modules instead of route handlers or UI components. Separate persistence, external providers, and background work behind small interfaces without building a framework. Prefer ordinary HTML forms and URLs for durable navigation; use optimistic interaction only when failure can be reconciled clearly. The product brief currently identifies Astro, D1, R2 as capability context. Preserve any required native, browser-only, edge, storage, real-time, or background-processing capability through a narrow adapter appropriate to the selected framework. If the core workflow genuinely requires native or browser APIs, keep that runtime as the primary execution surface rather than simulating inaccessible capabilities or inventing an unnecessary web surface. Integrate with Stripe Checkout and transactional email. For every integration: - List required environment variables in an .env.example without real secrets. - Add a small adapter with timeouts, normalized errors, and a deterministic local fake or development path. - Verify inbound signatures and deduplicate provider events where supported. - Keep credentials server-side, encrypt long-lived provider tokens at rest, and redact secrets and sensitive payloads from logs. - Define retry, backoff, and idempotency behavior for any side effect that can be repeated. SECURITY AND PRIVACY Grant file access only from verified, deduplicated payment webhooks, and sign every download URL with a short expiry tied to its sale. Validate, normalize, and length-limit all untrusted input on the server. Escape rendered content by default, sanitize any intentionally accepted markup, rate-limit public or abuse-prone actions, and use private object storage plus short-lived authorized URLs for sensitive files. Collect the minimum personal data necessary for the named workflow. Document retention and deletion behavior. Add specific protections for the riskier surfaces in this app, such as uploads, redirects, outbound requests, email delivery, OAuth, webhooks, CSV import or export, and real-time connections. ACCEPTANCE SCENARIOS Automate these app-specific scenarios at the most appropriate level: 1. Given the same paid webhook arrives three times, exactly one sale is recorded and one delivery email is sent. 2. Given an expired download link, the buyer can request a fresh one that is issued only to the original purchase email. 3. Given a refunded sale, its download links stop working, its license key fails verification, and the dashboard shows the refund. TESTING Add focused unit tests for state transitions, authorization predicates, normalization, date or money calculations, and other risky domain rules. Add integration tests for persistence constraints and each external adapter’s success, timeout, retry, and rejection paths. Add at least one browser-level test for every end-to-end journey above, including one small-screen viewport. Tests must use isolated data and run through a documented single command. OPERATIONS AND FAILURE RECOVERY Add structured server logs with request, job, or event correlation IDs but no secrets or unnecessarily sensitive data. Make failures actionable in both the interface and logs. Background work must expose pending, succeeded, failed, and retrying states where relevant; do not silently swallow errors. Include safe database migration and rollback guidance, seed data, backup and restore notes, external-data cleanup behavior, and a basic health or diagnostic path appropriate to the stack. DELIVERABLES Ship the working application, migrations, representative seed data, tests, .env.example, and a concise README. The README must cover prerequisites, local setup, environment variables, migrations, seed and test commands, deployment, integration setup, backup and restore, security decisions, and known limitations. Seed data should exercise the happy path plus at least one empty, failed, overdue, expired, archived, or permission-restricted state relevant to the product. DEFINITION OF DONE The app is complete when a fresh developer can follow the README, create and migrate the database, run the app, sign in as each relevant role, complete every named journey using real persisted data, refresh without losing state, recover from common failures, and use the core interface on phone and desktop. All acceptance scenarios pass, permission boundaries are covered by tests, and no core screen is left as a placeholder. NON-GOALS Do not build marketplace discovery, subscriptions or memberships, affiliate programs, VAT calculation, or physical goods.
You are building a production-ready software product named “Sellshelf”, a deliberately focused alternative to Gumroad. Build a complete, usable vertical slice—not a landing page, static mockup, or disconnected collection of components. WORKING AGREEMENT Before writing implementation code, produce a short technical plan that names the routes or pages, server actions or endpoints, data tables, important state transitions, authorization boundaries, background jobs, and external adapters. Resolve contradictions in favor of the narrow audience and non-goals below. Prefer a small, legible architecture over speculative abstraction, but do not omit persistence, validation, error handling, or tests. PRODUCT BRIEF Primary user: one creator selling a handful of digital products directly. Primary outcome: publish product pages, take payment through a hosted checkout, and deliver files only to verified buyers. Product principle: optimize the exact workflow below instead of copying the full breadth of Gumroad. A first-time user should understand what to do from the interface itself, without a tour or documentation. END-TO-END USER JOURNEYS Implement all of these flows through the real interface and persistent data layer: 1. The seller uploads a file, writes the product page, sets a price, previews the checkout flow, and publishes the product at its public URL. 2. A buyer pays through hosted checkout, receives an email with a signed expiring download link and a license key, and downloads the file. 3. The seller opens the dashboard, reviews recent sales, resends a delivery email to a buyer who lost it, and issues a refund that revokes the download link and license key. SCREENS AND INFORMATION ARCHITECTURE Build these as coherent responsive views. Each screen must specify its primary action, secondary actions, visible status, validation feedback, empty state, loading or pending state, success confirmation, and recoverable failure state. 1. Product admin: product list with published state, file uploads, price, cover image, description editor, and a license-key toggle. 2. Public product page: cover, description, price, a buy button into hosted checkout, and a clear success state after payment. 3. Delivery email and download: signed link with visible expiry, license key when applicable, remaining attempts, and a recovery path for expired links. 4. Sales dashboard: revenue totals, sale list with buyer email, product, and status, refund and resend actions, and webhook delivery health. CORE CAPABILITIES 1. product pages for files with price, cover, and description 2. hosted checkout through one payment provider 3. signed expiring download links delivered by email 4. license keys generated per sale for software products 5. a simple dashboard with sales, revenue, and refunds DETAILED BEHAVIOR AND BUSINESS RULES Treat these as server-enforced product requirements, not interface suggestions: 1. Grant download access only after a verified payment webhook commits; deduplicate provider events so one payment yields one sale and one delivery email. 2. Sign every download URL with an expiry and a sale reference, cap download attempts, and never expose bucket paths or permanent URLs. 3. Generate a unique license key per sale, verify keys against the sale record, and fail verification once the sale is refunded. 4. Store money as integer minor units, execute refunds through the payment provider, and revoke links and keys only after the provider confirms. DATA MODEL AND LIFECYCLE Design a small relational schema centered on Product, ProductFile, Sale, DownloadLink, LicenseKey. Before implementing it, document: 1. Each table’s purpose, primary key, ownership or tenant boundary, timestamps, status fields, and important attributes. 2. Foreign keys, uniqueness constraints, check constraints, indexes needed by the named screens, and transaction boundaries for multi-record changes. 3. The allowed lifecycle or state transitions, who may trigger each transition, which transitions are terminal or reversible, and what audit history must remain immutable. 4. Archive, retention, and deletion behavior, including what happens to dependent records and external files. 5. Idempotency strategy for submissions, jobs, imports, notifications, webhooks, or retries where applicable. Use migrations rather than ad-hoc schema creation. Store time instants consistently and retain named timezone context whenever local schedules or dates matter. Never rely on a counter, disabled button, or client-side check to preserve a business invariant. USERS, AUTHENTICATION, AND PERMISSIONS Implement only the roles required by the stated audience. Make the ownership and visibility model explicit before coding. Enforce authorization in every server-side query and mutation, including search, exports, attachments, live updates, and guessed URLs—not merely by hiding controls. Use secure session defaults, protect state-changing requests, and provide an understandable signed-out, expired-session, and forbidden state. Seed distinct users when multiple roles are required so permissions can be demonstrated and tested. INTERACTION AND VISUAL DIRECTION The product should feel fast, calm, focused, and credible rather than like a generic admin template. Use a clear visual hierarchy, restrained color, readable typography, generous hit targets, and consistent placement for primary actions. Start with server-rendered HTML and progressively enhance only the interactions that benefit from it. The core workflow must remain understandable if enhancement fails. Start with server-rendered Rails views and ordinary forms. Use Turbo for navigation, submissions, and server-driven updates, then Stimulus only for small browser-side behavior. Do not turn the product into a client-side SPA, and keep the core workflow usable when enhancement fails. Design mobile layouts intentionally instead of simply stacking desktop panels. Support keyboard navigation, visible focus, semantic landmarks, explicit labels, useful page titles, reduced-motion preferences, and screen-reader announcements for asynchronous results. Never use color alone to communicate state. Destructive actions require clear scope and confirmation; safe repeated actions should be idempotent. TECHNICAL DIRECTION Build this version with Ruby on Rails and Hotwire: Turbo for navigation, form submissions, and server-driven updates, and Stimulus for small browser-side behavior. Use RESTful controllers with strong parameters and explicit authorization, with domain transitions in testable models or small application services. Use Active Record migrations plus database-level constraints and transactions; Active Storage with an S3-compatible service for private files; Active Job with a durable queue backend for retryable work; Action Mailer for email; and Action Cable only when live updates are required. Keep domain rules in testable server-side modules instead of route handlers or UI components. Separate persistence, external providers, and background work behind small interfaces without building a framework. Prefer ordinary HTML forms and URLs for durable navigation; use optimistic interaction only when failure can be reconciled clearly. The product brief currently identifies Astro, D1, R2 as capability context. Preserve any required native, browser-only, edge, storage, real-time, or background-processing capability through a narrow adapter appropriate to the selected framework. If the core workflow genuinely requires native or browser APIs, keep that runtime as the primary execution surface rather than simulating inaccessible capabilities or inventing an unnecessary web surface. Integrate with Stripe Checkout and transactional email. For every integration: - List required environment variables in an .env.example without real secrets. - Add a small adapter with timeouts, normalized errors, and a deterministic local fake or development path. - Verify inbound signatures and deduplicate provider events where supported. - Keep credentials server-side, encrypt long-lived provider tokens at rest, and redact secrets and sensitive payloads from logs. - Define retry, backoff, and idempotency behavior for any side effect that can be repeated. SECURITY AND PRIVACY Grant file access only from verified, deduplicated payment webhooks, and sign every download URL with a short expiry tied to its sale. Validate, normalize, and length-limit all untrusted input on the server. Escape rendered content by default, sanitize any intentionally accepted markup, rate-limit public or abuse-prone actions, and use private object storage plus short-lived authorized URLs for sensitive files. Collect the minimum personal data necessary for the named workflow. Document retention and deletion behavior. Add specific protections for the riskier surfaces in this app, such as uploads, redirects, outbound requests, email delivery, OAuth, webhooks, CSV import or export, and real-time connections. ACCEPTANCE SCENARIOS Automate these app-specific scenarios at the most appropriate level: 1. Given the same paid webhook arrives three times, exactly one sale is recorded and one delivery email is sent. 2. Given an expired download link, the buyer can request a fresh one that is issued only to the original purchase email. 3. Given a refunded sale, its download links stop working, its license key fails verification, and the dashboard shows the refund. TESTING Add focused unit tests for state transitions, authorization predicates, normalization, date or money calculations, and other risky domain rules. Add integration tests for persistence constraints and each external adapter’s success, timeout, retry, and rejection paths. Add at least one browser-level test for every end-to-end journey above, including one small-screen viewport. Tests must use isolated data and run through a documented single command. OPERATIONS AND FAILURE RECOVERY Add structured server logs with request, job, or event correlation IDs but no secrets or unnecessarily sensitive data. Make failures actionable in both the interface and logs. Background work must expose pending, succeeded, failed, and retrying states where relevant; do not silently swallow errors. Include safe database migration and rollback guidance, seed data, backup and restore notes, external-data cleanup behavior, and a basic health or diagnostic path appropriate to the stack. DELIVERABLES Ship the working application, migrations, representative seed data, tests, .env.example, and a concise README. The README must cover prerequisites, local setup, environment variables, migrations, seed and test commands, deployment, integration setup, backup and restore, security decisions, and known limitations. Seed data should exercise the happy path plus at least one empty, failed, overdue, expired, archived, or permission-restricted state relevant to the product. DEFINITION OF DONE The app is complete when a fresh developer can follow the README, create and migrate the database, run the app, sign in as each relevant role, complete every named journey using real persisted data, refresh without losing state, recover from common failures, and use the core interface on phone and desktop. All acceptance scenarios pass, permission boundaries are covered by tests, and no core screen is left as a placeholder. NON-GOALS Do not build marketplace discovery, subscriptions or memberships, affiliate programs, VAT calculation, or physical goods.
Build just one piece
Not ready to replace all of Gumroad? Fine. These are the peculiar sub-problems hiding inside it — the parts that are actually interesting to build. Each one is a standalone prompt, scoped to an evening, no strings attached to the full build.
The webhook that gets paid three times and sells oncePayment providers retry. Your idempotency is the only thing between one sale and three.
Build idempotent payment webhook processing for a digital-products store. File access is granted only from verified provider webhooks, and providers redeliver events, retries, network flakes, out-of-order arrivals. Your job: any number of deliveries of the same payment produces exactly one sale and one delivery email. Verify the webhook signature first, rejecting anything unsigned or stale. Then dedupe structurally: store the provider's event id, or better the payment id, with a unique constraint, and insert the sale in the same transaction that records the event, so a concurrent duplicate delivery loses the insert race and exits cleanly instead of double-selling. Send the delivery email only after the sale commits, and make the send itself idempotent by recording it against the sale. Handle out-of-order events, a refund webhook arriving before you've seen its payment, by parking unknown references for retry rather than dropping them. Return 200 fast and queue slow work. Done when: three deliveries of one payment yield one sale row and one email, signature failures are rejected and logged, and an early refund event eventually reconciles.
The download link with an expiry date and a memorySigned URLs tied to a sale, attempt caps, and recovery that only trusts the buyer’s inbox.
Build signed, expiring download delivery for purchased files. Files live in private object storage; buyers never see bucket paths or permanent URLs. After a verified sale, mint a download token carrying the sale reference, an expiry of a day or two, and a signature, delivered by email. On redemption, verify the signature, check expiry, confirm the underlying sale is still valid and not refunded, count the attempt against a per-sale cap that tolerates a flaky connection but resists mass sharing, then respond with a short-lived storage URL or stream the file, so nothing durable ever leaks. Expired links get a recovery path instead of a dead end: a request form that issues a fresh link only to the sale's original purchase email, never to whoever holds the old URL. Refunds revoke everything, verification fails the moment the sale is marked refunded, regardless of remaining time or attempts. Done when: links stop working at expiry and cap, recovery mails the original buyer only, and a refunded sale's links die instantly.
The license key that phones home to its saleGenerated per sale, verified against the record, dead the moment the money comes back.
Build license key issuance and verification for software sold online. Each sale of a key-enabled product generates one unique license key, formatted for humans to read over a support call, grouped uppercase segments without ambiguous characters like O, 0, I, and 1, from a cryptographically random source, with a uniqueness constraint backstopping the astronomically unlikely collision. The key is stored against its sale and emailed with the download link. Expose a verification endpoint the software calls: given a key, return valid or invalid plus the product it belongs to. Validity is a live property of the sale, not the string: a refunded sale's key fails verification immediately, and there is nothing intrinsic in the key's format to forge or reverse-engineer, the database is the truth. Rate-limit verification to blunt brute-force scanning, log verification attempts per key for support forensics, and let the seller regenerate a compromised key, retiring the old one. Done when: every sale gets a unique well-formed key, verification tracks refund status in real time, and brute-forcing the keyspace is both rate-limited and statistically hopeless.
The refund that waits for the money before pulling the plugProvider confirms first. Then, and only then, links die and keys fail.
Build the refund pipeline for a digital-products store. A refund spans two systems, the payment provider and your own records, and ordering is everything: revoke a buyer's access before the provider actually refunds and a failed refund leaves a paying customer locked out. Model it as a state machine on the sale: refund requested, pending at provider, confirmed, failed. The seller's refund button calls the provider's API and moves the sale to pending, changing nothing about access yet. Only the provider's refund-confirmed webhook, verified and deduplicated, moves the sale to refunded and, in that same transaction, revokes download links and marks the license key invalid. Handle the crossings: a refund webhook arriving before your API call returns (webhook wins, reconcile the pending state), a provider failure (surface it, sale returns to paid, access intact), and a refund initiated from the provider's own dashboard, which arrives as a webhook for a refund you never requested and must process identically. Done when: access survives until provider confirmation, dashboard-initiated refunds reconcile cleanly, and no ordering of API responses and webhooks strands a sale in a wrong state.
Frequently asked questions
How long does it take to build your own Gumroad?
A basic version — product pages, checkout, signed delivery links — takes about 12 hours. Roughly 4 days gets you a solid v1 with discount codes, file versions, pay-what-you-want, receipts. Matching everything Gumroad really does (marketplace discovery, memberships, affiliates, vat handling) is closer to 3 months+, which is exactly why you should scope down instead.
How much does Gumroad cost if I keep subscribing?
Gumroad runs $10–$50 per month on public paid plans, which is $120–$600 per year. A focused self-built replacement costs your build time plus close-to-zero hosting.
What stack should I use to build a Gumroad alternative?
The build prompt on this page ships in four flavors: the AHA stack (Astro, HTMX, Alpine.js), Next.js, Laravel, and Ruby on Rails. The capability context for this product is Astro, D1, R2. Pick the stack you already know — the scope matters more than the framework.
What features does a minimal Gumroad replacement need?
A useful v1 needs: product pages for files with price, cover, and description; hosted checkout through one payment provider; signed expiring download links delivered by email; license keys generated per sale for software products; a simple dashboard with sales, revenue, and refunds. Everything else is scope creep until you personally miss it.
What should I deliberately not build?
Do not build marketplace discovery, subscriptions or memberships, affiliate programs, VAT calculation, or physical goods.
Does this build also replace Lemon Squeezy, Payhip and Sellfy?
Yes. Gumroad, Lemon Squeezy, Payhip and Sellfy all solve the same core job — publish product pages, take payment through a hosted checkout, and deliver files only to verified buyers. The scoped v1 on this page covers what most people use any of them for, so one focused build replaces whichever you currently pay for.