v0.2.0 - External API integration readiness documentation milestone

v0.2.0 Release Notes

Summary

v0.2.0 is the second documentation milestone for the fintech external API reference architecture.

It builds on v0.1.0 by adding external integration readiness material:

• webhook delivery model,
• stable error code reference,
• external integration guide,
• implementation-neutral review checklist,
• ADR-0007 through ADR-0010.

What changed since v0.1.0

Area	Document	Purpose
Webhook delivery	docs/webhook-delivery-model.md	Signed, company-scoped webhook delivery, retries, idempotency, failure handling, and auditability.
Error handling	docs/error-code-reference.md	Stable external error codes, HTTP status mapping, retry semantics, and audit expectations.
Integration onboarding	docs/integration-guide.md	Implementation-neutral guidance for API key use, idempotency, rate limits, webhooks, token lifecycle, and logging.
Readiness review	docs/review-checklist.md	Checklist for architecture, security, product, and integration readiness review.
Architecture decisions	ADR-0007 through ADR-0010	Decisions for signed webhook delivery, stable error codes, integration guide, and readiness checklist.

Included documentation

• Documentation index
• Problem statement
• Architecture overview
• Security boundaries
• Company-scoped API key model
• Scope and permission model
• Audit log model
• Rate limiting and abuse detection model
• Token lifecycle and revocation model
• External API contract examples
• Threat model
• Webhook delivery model
• Error code reference
• Integration guide
• Review checklist
• ADR-0001 through ADR-0010

Architecture decisions added in v0.2.0

• ADR-0007: Use signed webhook delivery model.
• ADR-0008: Use stable external error codes.
• ADR-0009: Use integration guide for external API onboarding.
• ADR-0010: Use review checklist for external API readiness.

What is intentionally not included

• Application code
• Production deployment
• Cloud-specific implementation
• Legal/compliance mapping
• OpenAPI/YAML contract
• SDKs or client libraries
• Automated tests

Next possible increments

• OpenAPI example file
• Webhook event schema catalogue
• Sample review worksheet
• Sequence diagrams
• API lifecycle/versioning policy
• Sample architecture review package
• v0.2.0 public announcement post

Notes

This release is a documentation milestone, not a production implementation.