Vibecode Sendcore

You are building a lean indie version of Sendcore.

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 =====
# Sendcore indie build

## Goal

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

## Scope

Build a private Shopify app that syncs your products and customers, composes an HTML campaign with a product block, and sends it to a consented segment through your own email provider key.

## 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:
- App Store distribution: OAuth install, app review and the mandatory GDPR data webhooks
- billing that appears on the merchant's own Shopify invoice instead of a separate card
- domain authentication onboarding and per-tenant sender reputation
- bounce, complaint and suppression handling
- order-level revenue attribution and automations that fire on real store events

If those capabilities are essential, use listmonk 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 private Shopify campaign sender for one store I already own. Not a SaaS, not multi-tenant, no signup. Requirements:

- Node 22 + Fastify + better-sqlite3, server-rendered HTML, no client framework.
- Read the store with a Shopify custom app Admin API token I create myself
  (read_products, read_customers, read_orders); no OAuth, no App Store install flow.
- Send through one bulk email provider with my API key and my already-authenticated
  sending domain; both in .env, ship a .env.example.
- SQLite tables: contacts (email, consent state, source, created_at), products cached
  from Shopify, campaigns (subject, body_html, status, sent_at), and sends
  (contact_id, campaign_id, status, error).
- Every contact carries an explicit consent state. Never send to an unsubscribed or
  unconsented contact, and prove that with a test.
- Every email gets a working one-click unsubscribe link plus List-Unsubscribe
  headers, backed by a signed token and honoured immediately.
- The composer is a plain HTML textarea plus a product picker that inserts image,
  title, price, and link from the synced cache. Render with inline styles and a
  table layout so it survives Gmail and Outlook; no external stylesheets or web fonts.
- Always send a test to myself first, and require a typed confirmation of the
  recipient count before any real send.
- Send in batches with retry and backoff, one send row per recipient, so a crash
  resumes instead of double-sending. Report delivered and failed from the sends
  table only; do not invent open or click tracking.
- CSV import and export for contacts so the data is never trapped in the app.
- Tests: the consent gate, the unsubscribe token, batch resume, and one end-to-end
  campaign against a mocked provider.
- README states what this is not: no deliverability operations, no bounce or
  complaint processing, no App Store distribution, no billing. Say plainly that real
  volume from a cold domain lands in spam, and warmup is now the reader's job.

## Required capabilities

- Node.js 22
- SQLite
- Shopify custom app Admin API token (read_products, read_customers, read_orders)
- Bulk email provider key in .env
- A sending domain you control, with SPF and DKIM already verified

## 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 Sendcore.

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 =====
# Sendcore indie build

## Goal

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

## Scope

Build a private Shopify app that syncs your products and customers, composes an HTML campaign with a product block, and sends it to a consented segment through your own email provider key.

## 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:
- App Store distribution: OAuth install, app review and the mandatory GDPR data webhooks
- billing that appears on the merchant's own Shopify invoice instead of a separate card
- domain authentication onboarding and per-tenant sender reputation
- bounce, complaint and suppression handling
- order-level revenue attribution and automations that fire on real store events

If those capabilities are essential, use listmonk 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 private Shopify campaign sender for one store I already own. Not a SaaS, not multi-tenant, no signup. Requirements:

- Node 22 + Fastify + better-sqlite3, server-rendered HTML, no client framework.
- Read the store with a Shopify custom app Admin API token I create myself
  (read_products, read_customers, read_orders); no OAuth, no App Store install flow.
- Send through one bulk email provider with my API key and my already-authenticated
  sending domain; both in .env, ship a .env.example.
- SQLite tables: contacts (email, consent state, source, created_at), products cached
  from Shopify, campaigns (subject, body_html, status, sent_at), and sends
  (contact_id, campaign_id, status, error).
- Every contact carries an explicit consent state. Never send to an unsubscribed or
  unconsented contact, and prove that with a test.
- Every email gets a working one-click unsubscribe link plus List-Unsubscribe
  headers, backed by a signed token and honoured immediately.
- The composer is a plain HTML textarea plus a product picker that inserts image,
  title, price, and link from the synced cache. Render with inline styles and a
  table layout so it survives Gmail and Outlook; no external stylesheets or web fonts.
- Always send a test to myself first, and require a typed confirmation of the
  recipient count before any real send.
- Send in batches with retry and backoff, one send row per recipient, so a crash
  resumes instead of double-sending. Report delivered and failed from the sends
  table only; do not invent open or click tracking.
- CSV import and export for contacts so the data is never trapped in the app.
- Tests: the consent gate, the unsubscribe token, batch resume, and one end-to-end
  campaign against a mocked provider.
- README states what this is not: no deliverability operations, no bounce or
  complaint processing, no App Store distribution, no billing. Say plainly that real
  volume from a cold domain lands in spam, and warmup is now the reader's job.

## Required capabilities

- Node.js 22
- SQLite
- Shopify custom app Admin API token (read_products, read_customers, read_orders)
- Bulk email provider key in .env
- A sending domain you control, with SPF and DKIM already verified

## 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 Sendcore.

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 =====
# Sendcore product brief

## Problem

The editor is the copyable part. A coding agent will happily build a private Shopify app that pulls your products, composes an HTML campaign and sends it with your own provider key, and for one store that is genuinely useful. What does not fall out of a one-shot is everything that makes it a product a merchant can run a business on: a listed App Store app with OAuth, mandatory GDPR data webhooks and billing that lands on the merchant's own Shopify invoice, per-tenant domain authentication with the DNS handholding it needs, and the consent, suppression and bounce records that keep sending both legal and delivered. Worth saying plainly: Sendcore is small and recent, with no audience network and no proprietary dataset to hide behind. It survives on platform surface, compliance plumbing and the unglamorous backlog that only real merchant sending reveals, which is a narrower moat than Klaviyo's and an honest one.

## Product outcome

Build a private Shopify app that syncs your products and customers, composes an HTML campaign with a product block, and sends it to a consented segment through your own email provider key.

## Target user

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

## Required capabilities

- Node.js 22
- SQLite
- Shopify custom app Admin API token (read_products, read_customers, read_orders)
- Bulk email provider key in .env
- A sending domain you control, with SPF and DKIM already verified

## Explicit non-goals for v1

- App Store distribution: OAuth install, app review and the mandatory GDPR data webhooks
- billing that appears on the merchant's own Shopify invoice instead of a separate card
- domain authentication onboarding and per-tenant sender reputation
- bounce, complaint and suppression handling
- order-level revenue attribution and automations that fire on real store events

## 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 private Shopify campaign sender for one store I already own. Not a SaaS, not multi-tenant, no signup. Requirements:

- Node 22 + Fastify + better-sqlite3, server-rendered HTML, no client framework.
- Read the store with a Shopify custom app Admin API token I create myself
  (read_products, read_customers, read_orders); no OAuth, no App Store install flow.
- Send through one bulk email provider with my API key and my already-authenticated
  sending domain; both in .env, ship a .env.example.
- SQLite tables: contacts (email, consent state, source, created_at), products cached
  from Shopify, campaigns (subject, body_html, status, sent_at), and sends
  (contact_id, campaign_id, status, error).
- Every contact carries an explicit consent state. Never send to an unsubscribed or
  unconsented contact, and prove that with a test.
- Every email gets a working one-click unsubscribe link plus List-Unsubscribe
  headers, backed by a signed token and honoured immediately.
- The composer is a plain HTML textarea plus a product picker that inserts image,
  title, price, and link from the synced cache. Render with inline styles and a
  table layout so it survives Gmail and Outlook; no external stylesheets or web fonts.
- Always send a test to myself first, and require a typed confirmation of the
  recipient count before any real send.
- Send in batches with retry and backoff, one send row per recipient, so a crash
  resumes instead of double-sending. Report delivered and failed from the sends
  table only; do not invent open or click tracking.
- CSV import and export for contacts so the data is never trapped in the app.
- Tests: the consent gate, the unsubscribe token, batch resume, and one end-to-end
  campaign against a mocked provider.
- README states what this is not: no deliverability operations, no bounce or
  complaint processing, no App Store distribution, no billing. Say plainly that real
  volume from a cold domain lands in spam, and warmup is now the reader's job.

## 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 Sendcore capabilities as implemented. The v1 non-goals in `PRODUCT.md` remain user-visible limitations until they are deliberately delivered.

# Sendcore indie build

## Goal

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

## Scope

Build a private Shopify app that syncs your products and customers, composes an HTML campaign with a product block, and sends it to a consented segment through your own email provider key.

## 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:
- App Store distribution: OAuth install, app review and the mandatory GDPR data webhooks
- billing that appears on the merchant's own Shopify invoice instead of a separate card
- domain authentication onboarding and per-tenant sender reputation
- bounce, complaint and suppression handling
- order-level revenue attribution and automations that fire on real store events

If those capabilities are essential, use listmonk 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 private Shopify campaign sender for one store I already own. Not a SaaS, not multi-tenant, no signup. Requirements:

- Node 22 + Fastify + better-sqlite3, server-rendered HTML, no client framework.
- Read the store with a Shopify custom app Admin API token I create myself
  (read_products, read_customers, read_orders); no OAuth, no App Store install flow.
- Send through one bulk email provider with my API key and my already-authenticated
  sending domain; both in .env, ship a .env.example.
- SQLite tables: contacts (email, consent state, source, created_at), products cached
  from Shopify, campaigns (subject, body_html, status, sent_at), and sends
  (contact_id, campaign_id, status, error).
- Every contact carries an explicit consent state. Never send to an unsubscribed or
  unconsented contact, and prove that with a test.
- Every email gets a working one-click unsubscribe link plus List-Unsubscribe
  headers, backed by a signed token and honoured immediately.
- The composer is a plain HTML textarea plus a product picker that inserts image,
  title, price, and link from the synced cache. Render with inline styles and a
  table layout so it survives Gmail and Outlook; no external stylesheets or web fonts.
- Always send a test to myself first, and require a typed confirmation of the
  recipient count before any real send.
- Send in batches with retry and backoff, one send row per recipient, so a crash
  resumes instead of double-sending. Report delivered and failed from the sends
  table only; do not invent open or click tracking.
- CSV import and export for contacts so the data is never trapped in the app.
- Tests: the consent gate, the unsubscribe token, batch resume, and one end-to-end
  campaign against a mocked provider.
- README states what this is not: no deliverability operations, no bounce or
  complaint processing, no App Store distribution, no billing. Say plainly that real
  volume from a cold domain lands in spam, and warmup is now the reader's job.

## Required capabilities

- Node.js 22
- SQLite
- Shopify custom app Admin API token (read_products, read_customers, read_orders)
- Bulk email provider key in .env
- A sending domain you control, with SPF and DKIM already verified

## 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.

# Sendcore product brief

## Problem

The editor is the copyable part. A coding agent will happily build a private Shopify app that pulls your products, composes an HTML campaign and sends it with your own provider key, and for one store that is genuinely useful. What does not fall out of a one-shot is everything that makes it a product a merchant can run a business on: a listed App Store app with OAuth, mandatory GDPR data webhooks and billing that lands on the merchant's own Shopify invoice, per-tenant domain authentication with the DNS handholding it needs, and the consent, suppression and bounce records that keep sending both legal and delivered. Worth saying plainly: Sendcore is small and recent, with no audience network and no proprietary dataset to hide behind. It survives on platform surface, compliance plumbing and the unglamorous backlog that only real merchant sending reveals, which is a narrower moat than Klaviyo's and an honest one.

## Product outcome

Build a private Shopify app that syncs your products and customers, composes an HTML campaign with a product block, and sends it to a consented segment through your own email provider key.

## Target user

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

## Required capabilities

- Node.js 22
- SQLite
- Shopify custom app Admin API token (read_products, read_customers, read_orders)
- Bulk email provider key in .env
- A sending domain you control, with SPF and DKIM already verified

## Explicit non-goals for v1

- App Store distribution: OAuth install, app review and the mandatory GDPR data webhooks
- billing that appears on the merchant's own Shopify invoice instead of a separate card
- domain authentication onboarding and per-tenant sender reputation
- bounce, complaint and suppression handling
- order-level revenue attribution and automations that fire on real store events

## 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 private Shopify campaign sender for one store I already own. Not a SaaS, not multi-tenant, no signup. Requirements:

- Node 22 + Fastify + better-sqlite3, server-rendered HTML, no client framework.
- Read the store with a Shopify custom app Admin API token I create myself
  (read_products, read_customers, read_orders); no OAuth, no App Store install flow.
- Send through one bulk email provider with my API key and my already-authenticated
  sending domain; both in .env, ship a .env.example.
- SQLite tables: contacts (email, consent state, source, created_at), products cached
  from Shopify, campaigns (subject, body_html, status, sent_at), and sends
  (contact_id, campaign_id, status, error).
- Every contact carries an explicit consent state. Never send to an unsubscribed or
  unconsented contact, and prove that with a test.
- Every email gets a working one-click unsubscribe link plus List-Unsubscribe
  headers, backed by a signed token and honoured immediately.
- The composer is a plain HTML textarea plus a product picker that inserts image,
  title, price, and link from the synced cache. Render with inline styles and a
  table layout so it survives Gmail and Outlook; no external stylesheets or web fonts.
- Always send a test to myself first, and require a typed confirmation of the
  recipient count before any real send.
- Send in batches with retry and backoff, one send row per recipient, so a crash
  resumes instead of double-sending. Report delivered and failed from the sends
  table only; do not invent open or click tracking.
- CSV import and export for contacts so the data is never trapped in the app.
- Tests: the consent gate, the unsubscribe token, batch resume, and one end-to-end
  campaign against a mocked provider.
- README states what this is not: no deliverability operations, no bounce or
  complaint processing, no App Store distribution, no billing. Say plainly that real
  volume from a cold domain lands in spam, and warmup is now the reader's job.

## 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 Sendcore 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