Vibecode Bitly

You are building a lean indie version of Bitly.

Create the following project files first, then implement the application by following them. Keep the files updated as decisions change. Do not collapse this into a single README or prompt.

===== README.md =====
# Bitly indie build

## Goal

Build the smallest trustworthy replacement for the core Bitly workflow for one developer or a tiny team.

## Scope

Map a short slug to a destination, 302 to it, log the click with device and country, and render a QR code for any link.

## Quick start

1. Install the documented dependencies.
2. Copy `.env.example` to `.env`.
3. Run the development command chosen during implementation.
4. Complete the acceptance checks in `BUILD_PLAN.md`.

## Honest limits

This build deliberately does not replace:
- links that outlive your own infrastructure · a domain you stop renewing takes every link with it
- bit.ly's recognition in the link itself, which cuts both ways now that shorteners get spam-filtered
- bundled QR code management, landing pages, and campaign grouping
- city-level and device-level analytics rollups without building them
- an SLA and someone to call

If those capabilities are essential, use Dub instead of pretending the gap is solved.

===== AGENTS.md =====
# Agent instructions

- Optimize for a working, understandable weekend build.
- Prefer the fewest moving parts that satisfy the brief.
- Do not invent cryptography, security guarantees, APIs, or compliance claims.
- Keep secrets out of source control and logs.
- Add focused tests for destructive, security-sensitive, and data-loss paths.
- Run the project checks before declaring the build complete.
- Record any deliberate shortcut in the README under "Tradeoffs".

===== BUILD_PLAN.md =====
# Build plan

## Original build brief

Build me a link shortener with click analytics and QR codes to replace Bitly. Requirements:

- Cloudflare Workers via wrangler: KV for the slug lookup, D1 for the click
  log. Free tier, and it runs on my own domain.
- A worker on go.mydomain.com/{slug} reads KV and 302s, writing the click to
  D1 inside ctx.waitUntil so the redirect never waits on the database.
- Slugs are random 6-character base62 by default, but I can set a custom
  back-half, and creating one that already exists fails loudly instead of
  overwriting it.
- Log per click: slug, timestamp, country and city from request.cf,
  device type parsed from the user-agent, and referer.
- Generate a PNG QR code for any link with the qrcode npm package, served at
  /qr/{slug} and cached, so print material points at the same tracked link.
- Optional expiry and a click cap per link · past either, 302 to a fallback
  URL I set instead of returning a 404.
- An /admin page behind one password (wrangler secret) listing links with
  clicks per day, plus top countries and device split per link.
- Secrets via wrangler secret, never in wrangler.toml. No accounts, no
  third-party analytics, no telemetry.
- README: wrangler setup, the KV namespace and D1 database, the DNS record,
  and a warning that these links die with the domain, so use a domain you
  intend to keep renewing.

## Required capabilities

- Cloudflare account (Workers, KV, D1)
- a domain you control
- wrangler CLI

## Delivery order

1. Scaffold the smallest runnable application and document its commands.
2. Implement the primary data model and core workflow.
3. Add validation, safe failure states, and persistence.
4. Cover the critical path with automated tests.
5. Exercise a clean install from the README and fix every missing step.

## Done when

- A new user can go from clone to first successful workflow using only the README.
- The core workflow works without paid infrastructure unless the brief requires it.
- Tests cover the highest-risk behavior.
- Known limitations are explicit rather than hidden.

===== .env.example =====
# Copy to .env and document every variable when it is introduced.
# Never put real credentials in this file.

APP_ENV=development
# Add only values required by the selected implementation.

You are building a lean indie version of Bitly.

Create the following project files first, then implement the application by following them. Keep the files updated as decisions change. Do not collapse this into a single README or prompt.

===== README.md =====
# Bitly indie build

## Goal

Build the smallest trustworthy replacement for the core Bitly workflow for one developer or a tiny team.

## Scope

Map a short slug to a destination, 302 to it, log the click with device and country, and render a QR code for any link.

## Quick start

1. Install the documented dependencies.
2. Copy `.env.example` to `.env`.
3. Run the development command chosen during implementation.
4. Complete the acceptance checks in `BUILD_PLAN.md`.

## Honest limits

This build deliberately does not replace:
- links that outlive your own infrastructure · a domain you stop renewing takes every link with it
- bit.ly's recognition in the link itself, which cuts both ways now that shorteners get spam-filtered
- bundled QR code management, landing pages, and campaign grouping
- city-level and device-level analytics rollups without building them
- an SLA and someone to call

If those capabilities are essential, use Dub instead of pretending the gap is solved.

===== AGENTS.md =====
# Agent instructions

- Optimize for a working, understandable weekend build.
- Prefer the fewest moving parts that satisfy the brief.
- Do not invent cryptography, security guarantees, APIs, or compliance claims.
- Keep secrets out of source control and logs.
- Add focused tests for destructive, security-sensitive, and data-loss paths.
- Run the project checks before declaring the build complete.
- Record any deliberate shortcut in the README under "Tradeoffs".

===== BUILD_PLAN.md =====
# Build plan

## Original build brief

Build me a link shortener with click analytics and QR codes to replace Bitly. Requirements:

- Cloudflare Workers via wrangler: KV for the slug lookup, D1 for the click
  log. Free tier, and it runs on my own domain.
- A worker on go.mydomain.com/{slug} reads KV and 302s, writing the click to
  D1 inside ctx.waitUntil so the redirect never waits on the database.
- Slugs are random 6-character base62 by default, but I can set a custom
  back-half, and creating one that already exists fails loudly instead of
  overwriting it.
- Log per click: slug, timestamp, country and city from request.cf,
  device type parsed from the user-agent, and referer.
- Generate a PNG QR code for any link with the qrcode npm package, served at
  /qr/{slug} and cached, so print material points at the same tracked link.
- Optional expiry and a click cap per link · past either, 302 to a fallback
  URL I set instead of returning a 404.
- An /admin page behind one password (wrangler secret) listing links with
  clicks per day, plus top countries and device split per link.
- Secrets via wrangler secret, never in wrangler.toml. No accounts, no
  third-party analytics, no telemetry.
- README: wrangler setup, the KV namespace and D1 database, the DNS record,
  and a warning that these links die with the domain, so use a domain you
  intend to keep renewing.

## Required capabilities

- Cloudflare account (Workers, KV, D1)
- a domain you control
- wrangler CLI

## Delivery order

1. Scaffold the smallest runnable application and document its commands.
2. Implement the primary data model and core workflow.
3. Add validation, safe failure states, and persistence.
4. Cover the critical path with automated tests.
5. Exercise a clean install from the README and fix every missing step.

## Done when

- A new user can go from clone to first successful workflow using only the README.
- The core workflow works without paid infrastructure unless the brief requires it.
- Tests cover the highest-risk behavior.
- Known limitations are explicit rather than hidden.

===== .env.example =====
# Copy to .env and document every variable when it is introduced.
# Never put real credentials in this file.

APP_ENV=development
# Add only values required by the selected implementation.

You are building a production product version of Bitly.

Create the following project files first, then implement the application by following them. Keep the files updated as decisions change. Do not collapse this into a single README or prompt.

===== PRODUCT.md =====
# Bitly product brief

## Problem

A slug, a lookup, a 302, and a row in a table. Cloudflare Workers plus KV and D1 does the whole job on the free tier, and QR codes are one library call. The only thing you are really buying is that bit.ly resolves links created in 2012 and will presumably still resolve them in 2032, which is an institutional promise rather than a technical one. If the links are going in a magazine ad or on packaging, that promise is worth something. If they are going in this week's newsletter, it is worth nothing, and Growth is 420 USD a year.

## Product outcome

Map a short slug to a destination, 302 to it, log the click with device and country, and render a QR code for any link.

## Target user

A serious builder who needs a maintainable product foundation rather than a one-off demo.

## Required capabilities

- Cloudflare account (Workers, KV, D1)
- a domain you control
- wrangler CLI

## Explicit non-goals for v1

- links that outlive your own infrastructure · a domain you stop renewing takes every link with it
- bit.ly's recognition in the link itself, which cuts both ways now that shorteners get spam-filtered
- bundled QR code management, landing pages, and campaign grouping
- city-level and device-level analytics rollups without building them
- an SLA and someone to call

## Success criteria

- The primary workflow is measurable end to end.
- Setup is reproducible in a clean environment.
- Failure, recovery, and support paths are documented.
- Product claims match what the implementation actually guarantees.

===== ARCHITECTURE.md =====
# Architecture

## Starting brief

Build me a link shortener with click analytics and QR codes to replace Bitly. Requirements:

- Cloudflare Workers via wrangler: KV for the slug lookup, D1 for the click
  log. Free tier, and it runs on my own domain.
- A worker on go.mydomain.com/{slug} reads KV and 302s, writing the click to
  D1 inside ctx.waitUntil so the redirect never waits on the database.
- Slugs are random 6-character base62 by default, but I can set a custom
  back-half, and creating one that already exists fails loudly instead of
  overwriting it.
- Log per click: slug, timestamp, country and city from request.cf,
  device type parsed from the user-agent, and referer.
- Generate a PNG QR code for any link with the qrcode npm package, served at
  /qr/{slug} and cached, so print material points at the same tracked link.
- Optional expiry and a click cap per link · past either, 302 to a fallback
  URL I set instead of returning a 404.
- An /admin page behind one password (wrangler secret) listing links with
  clicks per day, plus top countries and device split per link.
- Secrets via wrangler secret, never in wrangler.toml. No accounts, no
  third-party analytics, no telemetry.
- README: wrangler setup, the KV namespace and D1 database, the DNS record,
  and a warning that these links die with the domain, so use a domain you
  intend to keep renewing.

## Boundaries

Separate the product into replaceable modules for interface, application logic, persistence, external integrations, and operational concerns. Keep domain logic independent from delivery frameworks and vendors.

## Production baseline

- Configuration: validated at startup with safe local defaults where possible.
- Security: least privilege, input validation, secret redaction, rate limits on abuse-prone paths, and no invented security primitives.
- Data: explicit schema and migrations, transactional writes where integrity matters, backup and restore instructions.
- Integrations: adapters around third-party providers, idempotent webhook or job processing, bounded retries, and timeouts.
- Observability: structured logs with request or operation IDs, an error-tracking hook, and health/readiness checks where a server exists.
- Quality: unit tests for domain rules, integration tests at module boundaries, and one end-to-end critical-path test.

## Decision records

For each major dependency, document why it was chosen, its failure mode, and how it can be replaced. Do not introduce infrastructure until a requirement justifies it.

===== AGENTS.md =====
# Agent instructions

- Read `PRODUCT.md` and `ARCHITECTURE.md` before changing code.
- Implement milestone by milestone; keep each change reviewable and leave the application runnable.
- Treat authentication, payments, encryption, imports, webhooks, and destructive actions as high-risk boundaries when present.
- Never invent cryptography or silently weaken a requirement to make a test pass.
- Use provider interfaces for external services and deterministic fakes in tests.
- Add migrations and rollback or recovery notes for persistent data changes.
- Log useful operational context without credentials, tokens, passwords, or personal data.
- Update documentation and run all checks before completing a milestone.

===== MILESTONES.md =====
# Delivery milestones

## M0 — Decisions and scaffold

- Confirm the runtime, persistence model, threat boundaries, and deployment target.
- Create a reproducible local environment and continuous checks.

## M1 — Core workflow

- Implement the smallest end-to-end product path with validation and tests.
- Keep integrations behind interfaces.

## M2 — Trust layer

- Add secure failure behavior, recovery paths, audit-relevant events, and data safeguards.
- Test abuse cases and destructive operations.

## M3 — Operability

- Add structured logs, error reporting hooks, health signals, backup/restore documentation, and deployment configuration.

## M4 — Release gate

- Run a clean-install test, critical-path end-to-end test, dependency review, and documented rollback exercise.
- Compare the shipped behavior with `PRODUCT.md` and publish remaining limitations.

===== OPERATIONS.md =====
# Operations

## Before release

- Validate configuration and secrets at startup.
- Define backup, restore, and rollback procedures and test them.
- Document logs, error tracking, health signals, and alert ownership.
- Set dependency update and vulnerability review expectations.

## Incident checklist

1. Contain the issue without destroying evidence or user data.
2. Record the timeline and affected scope.
3. Rotate exposed secrets and revoke compromised sessions or credentials.
4. Restore from a verified source when needed.
5. Document the root cause, remediation, and regression test.

## Launch constraint

Do not market omitted Bitly capabilities as implemented. The v1 non-goals in `PRODUCT.md` remain user-visible limitations until they are deliberately delivered.

# Bitly indie build

## Goal

Build the smallest trustworthy replacement for the core Bitly workflow for one developer or a tiny team.

## Scope

Map a short slug to a destination, 302 to it, log the click with device and country, and render a QR code for any link.

## Quick start

1. Install the documented dependencies.
2. Copy `.env.example` to `.env`.
3. Run the development command chosen during implementation.
4. Complete the acceptance checks in `BUILD_PLAN.md`.

## Honest limits

This build deliberately does not replace:
- links that outlive your own infrastructure · a domain you stop renewing takes every link with it
- bit.ly's recognition in the link itself, which cuts both ways now that shorteners get spam-filtered
- bundled QR code management, landing pages, and campaign grouping
- city-level and device-level analytics rollups without building them
- an SLA and someone to call

If those capabilities are essential, use Dub instead of pretending the gap is solved.

# Agent instructions

- Optimize for a working, understandable weekend build.
- Prefer the fewest moving parts that satisfy the brief.
- Do not invent cryptography, security guarantees, APIs, or compliance claims.
- Keep secrets out of source control and logs.
- Add focused tests for destructive, security-sensitive, and data-loss paths.
- Run the project checks before declaring the build complete.
- Record any deliberate shortcut in the README under "Tradeoffs".

# Build plan

## Original build brief

Build me a link shortener with click analytics and QR codes to replace Bitly. Requirements:

- Cloudflare Workers via wrangler: KV for the slug lookup, D1 for the click
  log. Free tier, and it runs on my own domain.
- A worker on go.mydomain.com/{slug} reads KV and 302s, writing the click to
  D1 inside ctx.waitUntil so the redirect never waits on the database.
- Slugs are random 6-character base62 by default, but I can set a custom
  back-half, and creating one that already exists fails loudly instead of
  overwriting it.
- Log per click: slug, timestamp, country and city from request.cf,
  device type parsed from the user-agent, and referer.
- Generate a PNG QR code for any link with the qrcode npm package, served at
  /qr/{slug} and cached, so print material points at the same tracked link.
- Optional expiry and a click cap per link · past either, 302 to a fallback
  URL I set instead of returning a 404.
- An /admin page behind one password (wrangler secret) listing links with
  clicks per day, plus top countries and device split per link.
- Secrets via wrangler secret, never in wrangler.toml. No accounts, no
  third-party analytics, no telemetry.
- README: wrangler setup, the KV namespace and D1 database, the DNS record,
  and a warning that these links die with the domain, so use a domain you
  intend to keep renewing.

## Required capabilities

- Cloudflare account (Workers, KV, D1)
- a domain you control
- wrangler CLI

## Delivery order

1. Scaffold the smallest runnable application and document its commands.
2. Implement the primary data model and core workflow.
3. Add validation, safe failure states, and persistence.
4. Cover the critical path with automated tests.
5. Exercise a clean install from the README and fix every missing step.

## Done when

- A new user can go from clone to first successful workflow using only the README.
- The core workflow works without paid infrastructure unless the brief requires it.
- Tests cover the highest-risk behavior.
- Known limitations are explicit rather than hidden.

# Copy to .env and document every variable when it is introduced.
# Never put real credentials in this file.

APP_ENV=development
# Add only values required by the selected implementation.

# Bitly product brief

## Problem

A slug, a lookup, a 302, and a row in a table. Cloudflare Workers plus KV and D1 does the whole job on the free tier, and QR codes are one library call. The only thing you are really buying is that bit.ly resolves links created in 2012 and will presumably still resolve them in 2032, which is an institutional promise rather than a technical one. If the links are going in a magazine ad or on packaging, that promise is worth something. If they are going in this week's newsletter, it is worth nothing, and Growth is 420 USD a year.

## Product outcome

Map a short slug to a destination, 302 to it, log the click with device and country, and render a QR code for any link.

## Target user

A serious builder who needs a maintainable product foundation rather than a one-off demo.

## Required capabilities

- Cloudflare account (Workers, KV, D1)
- a domain you control
- wrangler CLI

## Explicit non-goals for v1

- links that outlive your own infrastructure · a domain you stop renewing takes every link with it
- bit.ly's recognition in the link itself, which cuts both ways now that shorteners get spam-filtered
- bundled QR code management, landing pages, and campaign grouping
- city-level and device-level analytics rollups without building them
- an SLA and someone to call

## Success criteria

- The primary workflow is measurable end to end.
- Setup is reproducible in a clean environment.
- Failure, recovery, and support paths are documented.
- Product claims match what the implementation actually guarantees.

# Architecture

## Starting brief

Build me a link shortener with click analytics and QR codes to replace Bitly. Requirements:

- Cloudflare Workers via wrangler: KV for the slug lookup, D1 for the click
  log. Free tier, and it runs on my own domain.
- A worker on go.mydomain.com/{slug} reads KV and 302s, writing the click to
  D1 inside ctx.waitUntil so the redirect never waits on the database.
- Slugs are random 6-character base62 by default, but I can set a custom
  back-half, and creating one that already exists fails loudly instead of
  overwriting it.
- Log per click: slug, timestamp, country and city from request.cf,
  device type parsed from the user-agent, and referer.
- Generate a PNG QR code for any link with the qrcode npm package, served at
  /qr/{slug} and cached, so print material points at the same tracked link.
- Optional expiry and a click cap per link · past either, 302 to a fallback
  URL I set instead of returning a 404.
- An /admin page behind one password (wrangler secret) listing links with
  clicks per day, plus top countries and device split per link.
- Secrets via wrangler secret, never in wrangler.toml. No accounts, no
  third-party analytics, no telemetry.
- README: wrangler setup, the KV namespace and D1 database, the DNS record,
  and a warning that these links die with the domain, so use a domain you
  intend to keep renewing.

## Boundaries

Separate the product into replaceable modules for interface, application logic, persistence, external integrations, and operational concerns. Keep domain logic independent from delivery frameworks and vendors.

## Production baseline

- Configuration: validated at startup with safe local defaults where possible.
- Security: least privilege, input validation, secret redaction, rate limits on abuse-prone paths, and no invented security primitives.
- Data: explicit schema and migrations, transactional writes where integrity matters, backup and restore instructions.
- Integrations: adapters around third-party providers, idempotent webhook or job processing, bounded retries, and timeouts.
- Observability: structured logs with request or operation IDs, an error-tracking hook, and health/readiness checks where a server exists.
- Quality: unit tests for domain rules, integration tests at module boundaries, and one end-to-end critical-path test.

## Decision records

For each major dependency, document why it was chosen, its failure mode, and how it can be replaced. Do not introduce infrastructure until a requirement justifies it.

# Agent instructions

- Read `PRODUCT.md` and `ARCHITECTURE.md` before changing code.
- Implement milestone by milestone; keep each change reviewable and leave the application runnable.
- Treat authentication, payments, encryption, imports, webhooks, and destructive actions as high-risk boundaries when present.
- Never invent cryptography or silently weaken a requirement to make a test pass.
- Use provider interfaces for external services and deterministic fakes in tests.
- Add migrations and rollback or recovery notes for persistent data changes.
- Log useful operational context without credentials, tokens, passwords, or personal data.
- Update documentation and run all checks before completing a milestone.

# Delivery milestones

## M0 — Decisions and scaffold

- Confirm the runtime, persistence model, threat boundaries, and deployment target.
- Create a reproducible local environment and continuous checks.

## M1 — Core workflow

- Implement the smallest end-to-end product path with validation and tests.
- Keep integrations behind interfaces.

## M2 — Trust layer

- Add secure failure behavior, recovery paths, audit-relevant events, and data safeguards.
- Test abuse cases and destructive operations.

## M3 — Operability

- Add structured logs, error reporting hooks, health signals, backup/restore documentation, and deployment configuration.

## M4 — Release gate

- Run a clean-install test, critical-path end-to-end test, dependency review, and documented rollback exercise.
- Compare the shipped behavior with `PRODUCT.md` and publish remaining limitations.

# Operations

## Before release

- Validate configuration and secrets at startup.
- Define backup, restore, and rollback procedures and test them.
- Document logs, error tracking, health signals, and alert ownership.
- Set dependency update and vulnerability review expectations.

## Incident checklist

1. Contain the issue without destroying evidence or user data.
2. Record the timeline and affected scope.
3. Rotate exposed secrets and revoke compromised sessions or credentials.
4. Restore from a verified source when needed.
5. Document the root cause, remediation, and regression test.

## Launch constraint

Do not market omitted Bitly capabilities as implemented. The v1 non-goals in `PRODUCT.md` remain user-visible limitations until they are deliberately delivered.

$ choose a build depth, inspect the files, then open the complete pack in your agent