Gumroad

Build me a focused digital products, courses and memberships workflow for the personal core of Gumroad. Requirements:

- Use Next.js 15, TypeScript, PostgreSQL, Drizzle ORM, Stripe Checkout, and S3-compatible storage. Model products, buyers, purchases, entitlements, and delivery receipts; keep stable source IDs and timestamps.
- Paid product context: Sell a few digital files through Stripe Checkout and a user-owned delivery page. Build only this DIY scope: Sell a small catalog of digital files through Stripe Checkout, deliver purchased files from a delivery page, and manage customers from a user-owned storefront.
- Implement products, variants, prices, files or lessons, coupons, customers, orders, and entitlements.
- Create a customer library with signed short-lived download or lesson URLs.
- Add order search, resend receipt, refund handoff, export, and an immutable event log.
- Use a local web page with input, progress, review, and export views. Required input or access: Stripe account; S3-compatible storage. Keep credentials in .env.
- Recovery: Use Stripe-hosted Checkout and verify every webhook signature and idempotency key.
- Acceptance: with one labelled sample, show the input, saved intermediate state, and exported result; verify this invariant: A repeated payment webhook cannot deliver twice; a refund must revoke the relevant access without deleting the audit trail.
- Out of scope: buyer familiarity, payment operations, tax handling, discovery, and creator workflow; marketplace discovery. Keep this a personal, inspectable workflow.
- Include a README with setup, a sample input, required keys or permissions, data location, and the supported scope.

# AGENTS.md — Build guide for Gumroad

## Project scope
Sell a small catalog of digital files through Stripe Checkout, deliver purchased files from a delivery page, and manage customers from a user-owned storefront.

Catalogue verdict: no. A consolation build is possible, but the paid product's decisive value sits outside a solo rebuild. For Gumroad, sell a few digital files through Stripe Checkout and a user-owned delivery page. The hard boundary is buyer familiarity, payment operations, tax handling, discovery, and creator workflow, plus payments, tax, distribution, and operations.
Use the implementation prompt below to define the deliverable. Complete each phase's acceptance checks before extending the scope.

## Working agreement
- Inspect the repository and its existing instructions before choosing paths, dependencies or commands. Keep one coherent stack and explain changes to the proposed architecture.
- Plan a vertical slice that accepts a real input and produces the useful output described below. Persist only the state the prompt calls for; respect memory-only and upstream-managed workflows. Use fixtures only when they are clearly labelled.
- After scaffolding, document the actual install, development, check and build commands in README and keep them synchronized with the package or project manifest. Do not report commands as successful unless they ran.
- Work in small steps. At handoff, list implemented flows, checks actually performed, remaining blockers, and any credentials or provider setup the owner must supply.
- Do not publish, spend money, contact customers, delete source data or run irreversible migrations without the project owner's authorization.

## Prerequisites
- Stripe account
- PostgreSQL
- S3-compatible storage
- public HTTPS deployment
- email provider

## Stack and architecture
- Use Next.js 15, TypeScript, PostgreSQL, Drizzle ORM, Stripe Checkout, and S3-compatible storage.
- Model products, buyers, purchases, entitlements, and delivery receipts; keep stable source IDs and timestamps.
- Interface for this digital products, courses and memberships workflow: a local web page with input, progress, review, and export views.

## Security and data integrity
- Use Stripe-hosted Checkout and verify every webhook signature and idempotency key.
- Keep API keys and OAuth secrets in .env; redact them from logs, generated files, and error responses.
- State the practical limit: buyer familiarity, payment operations, tax handling, discovery, and creator workflow.

## Agent implementation rules
- Project rule, data: Model products, buyers, purchases, entitlements, and delivery receipts; keep stable source IDs and timestamps.
- Project rule, behavior: Implement products, variants, prices, files or lessons, coupons, customers, orders, and entitlements.
- Project rule, recovery: Use Stripe-hosted Checkout and verify every webhook signature and idempotency key.

## Optional agent skills and references
No installable skill is listed for this guide; use the project rules and the stack documentation.

Read the linked SKILL.md and its dependencies before adding a skill. Select only the skills matching this project's runtime and task; their documentation does not supply API access, credentials or approval to perform external actions. Pin the reviewed revision where the tool supports it. Follow the chosen agent's documented project-level installation mechanism.

## Distribution ideas
These are optional planning notes. Obtain the owner's approval before publishing or contacting anyone.
- Demonstrate this digital products, courses and memberships operation with sample or user-owned data: Implement products, variants, prices, files or lessons, coupons, customers, orders, and entitlements.
- Show a concrete result or export: Create a customer library with signed short-lived download or lesson URLs.
- State the practical limit: buyer familiarity, payment operations, tax handling, discovery, and creator workflow.

## Engineering roadmap
1. Phase 1, architecture and data: Use Next.js 15, TypeScript, PostgreSQL, Drizzle ORM, Stripe Checkout, and S3-compatible storage. Model products, buyers, purchases, entitlements, and delivery receipts; keep stable source IDs and timestamps.
2. Phase 2, implement: Implement products, variants, prices, files or lessons, coupons, customers, orders, and entitlements.
3. Phase 3, implement: Create a customer library with signed short-lived download or lesson URLs.
4. Phase 4, review and output: Add order search, resend receipt, refund handoff, export, and an immutable event log. Create a customer library with signed short-lived download or lesson URLs.
5. Phase 5, recovery and acceptance: Use Stripe-hosted Checkout and verify every webhook signature and idempotency key. Verify this invariant with a saved fixture: A repeated payment webhook cannot deliver twice; a refund must revoke the relevant access without deleting the audit trail. State the practical limit: buyer familiarity, payment operations, tax handling, discovery, and creator workflow.

## Paid-product capabilities outside this build
- buyer familiarity, payment operations, tax handling, discovery, and creator workflow
- marketplace discovery
- tax remittance
- fraud operations
- advanced course and community tooling

## Implementation prompt
Build me a focused digital products, courses and memberships workflow for the personal core of Gumroad. Requirements:

- Use Next.js 15, TypeScript, PostgreSQL, Drizzle ORM, Stripe Checkout, and S3-compatible storage. Model products, buyers, purchases, entitlements, and delivery receipts; keep stable source IDs and timestamps.
- Paid product context: Sell a few digital files through Stripe Checkout and a user-owned delivery page. Build only this DIY scope: Sell a small catalog of digital files through Stripe Checkout, deliver purchased files from a delivery page, and manage customers from a user-owned storefront.
- Implement products, variants, prices, files or lessons, coupons, customers, orders, and entitlements.
- Create a customer library with signed short-lived download or lesson URLs.
- Add order search, resend receipt, refund handoff, export, and an immutable event log.
- Use a local web page with input, progress, review, and export views. Required input or access: Stripe account; S3-compatible storage. Keep credentials in .env.
- Recovery: Use Stripe-hosted Checkout and verify every webhook signature and idempotency key.
- Acceptance: with one labelled sample, show the input, saved intermediate state, and exported result; verify this invariant: A repeated payment webhook cannot deliver twice; a refund must revoke the relevant access without deleting the audit trail.
- Out of scope: buyer familiarity, payment operations, tax handling, discovery, and creator workflow; marketplace discovery. Keep this a personal, inspectable workflow.
- Include a README with setup, a sample input, required keys or permissions, data location, and the supported scope.

## Completion evidence
Demonstrate the prompt's acceptance scenarios against the scoped workflow. Include setup from a clean checkout and failure recovery. Check persistence across restart and export/restore only for the state the prompt says to store; for memory-only tools, confirm that temporary content is discarded as specified. Record actual results and remaining limitations. A detailed plan alone does not establish a working replacement.