Product P-07 / 08 / Code + docs $200 USD × TypeScript + Postgres

SaaS billing
reference architecture.

A working Stripe + idempotency + audit-log codebase, with proration, dunning, invoice retry — and the docs that explain every decision.

USD 200
One-time
8,400
LOC
94%
Test coverage
47
Documented decisions

A codebase that
runs, not a tutorial.

Clone, npm install, supply a Stripe test key, watch a working multi-tenant billing system come to life.

A / Foundation

Stripe + idempotency

The boring base layer, done right once.

  • Stripe API wrapper TypeScript
  • Idempotency keys PG-backed
  • Webhook verification replay-safe
  • Test mode harness CI-ready
  • Fixture data 12 scenarios
B / Lifecycle

Subscriptions & proration

The flows real customers actually hit.

  • Plan upgrades with proration
  • Downgrades at period end
  • Pause + resume fully tested
  • Cancellation flows with retention
  • Trial → paid edge-cased
C / Recovery

Dunning & retries

Failed payments handled like adults, not panic.

  • 3-stage dunning templated
  • Smart retry card-network aware
  • Grace period configurable
  • Customer notifications React Email
  • Recovery rate trend measured
D / Audit

Audit log

Every state change traceable; reconciles to Stripe daily.

  • Append-only log PG partitioned
  • Customer event API paginated
  • Daily reconciliation with Stripe
  • PII redaction per-field
  • Export job GDPR-ready

A repository
you’ll actually merge from.

MIT-style license for the code. Use it as a starting point, lift the parts you need, or run it as-is.

01

Git repository

TypeScript monorepo: API service, worker, admin UI, shared types, fixture data, end-to-end tests against Stripe test mode.

02

Postgres schema

Migrations included. Multi-tenant by default. Partitioned audit log. Idempotency table sized for production load.

03

47 documented decisions

An ADR per non-obvious choice: why this retry policy, why this dunning shape, why this proration approach.

04

End-to-end tests

94% coverage. Integration tests run against Stripe test mode; unit tests run offline. CI configuration included.

05

Migration guide

24-page PDF for adopting the patterns into your existing codebase, even if you can’t use the code wholesale.

Things buyers ask
on the first call.

If something isn’t answered here, ask in your intro email — we keep this list short on purpose.

Is this Stripe-only?+

The reference is Stripe. Patterns generalize cleanly to Paddle, Lemon Squeezy, or Chargebee. We have notes on the diff for each in the migration guide.

TypeScript only?+

The reference code is TypeScript. The patterns translate cleanly — we’ve included the equivalent shapes in pseudocode for Python and Go in the migration guide.

Why is it $200?+

It saves 8–12 senior-engineer weeks. We could keep it private and only ship it on Custom Software engagements (where it’s included), but more teams benefit from it as a standalone artifact.

Can we resell this in our product?+

Use it inside your product, yes. Resell it as a standalone product, no — that’s the only restriction in the license.

Need it customized
for your team?

We do bespoke kits, too. Send a paragraph about the problem and we’ll come back inside 48 hours.

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