Integration Contracts - Audit Trail Platform (ATP)¶

Contracts as code — ATP's integration contracts define precise, versioned, and testable interfaces for REST APIs, async messaging, webhooks, and SDK integration with contract-first development and automated validation.

📋 Documentation Generation Plan¶

This document will be generated in 4 cycles. Current progress:

Cycle	Topics	Estimated Lines	Status
Cycle 1	Contract-First Development & Overview (1-2)	~2,000	⏳ Not Started
Cycle 2	Contract Types & API Design (3-4)	~2,500	⏳ Not Started
Cycle 3	Contract Testing & Versioning (5-6)	~2,000	⏳ Not Started
Cycle 4	Contract Governance & Best Practices (7-8)	~1,500	⏳ Not Started

Total Estimated Lines: ~8,000

Purpose & Scope¶

This document serves as the navigation hub and overview for all integration contracts in the Audit Trail Platform (ATP), introducing contract-first development principles, explaining contract types (REST, messages, webhooks), and providing guided navigation to detailed contract specifications based on integration needs.

Key Contract Principles - Contract-First Development: Contracts defined before implementation - Versioned Contracts: All contracts versioned with semantic versioning - Backward Compatibility: Breaking changes avoided; managed through versions - Automated Validation: Contract tests run in CI/CD pipelines - Published Specifications: OpenAPI for REST, AsyncAPI for messaging, JSON Schema for webhooks - Consumer-Driven: Contracts consider consumer needs and use cases - Technology-Agnostic: Contracts independent of implementation technology

What this document covers

Introduce ATP's contract-first philosophy: Why contracts matter, benefits for ATP
Explain contract types: REST APIs, Message Schemas, Webhooks, SDK contracts
Provide navigation to contract specifications: Links organized by integration type
Define contract versioning strategy: Semantic versioning, compatibility rules, deprecation
Describe contract testing: Producer tests, consumer tests, contract validation
Outline contract governance: Who owns contracts, approval process, change management
Document shared contracts: Idempotency, correlation, tenancy, error handling
Specify contract evolution: Adding, changing, deprecating contracts safely

Out of scope (covered in linked documents)

Detailed REST API specifications (see rest-apis.md)
Complete message schemas (see message-schemas.md)
Webhook specifications (see webhooks.md)
Idempotency patterns (see shared/idempotency.md)
Domain model details (see ../aggregates-entities.md)
Implementation patterns (see ../../implementation/)

Readers & ownership

Integration Engineers (owners): Contract design, specification, testing, evolution
Backend Developers: API implementation, message handling, contract validation
Frontend Developers: REST API consumption, SDK usage
Partner Engineers: External system integration, webhook handling
QA/Test Engineers: Contract testing, validation, compatibility testing
Architects: Contract design patterns, versioning strategy, governance

Artifacts produced

Contract Index: This document - navigation hub for all contracts
OpenAPI Specifications: REST API contracts (ingestion, query, policy, export)
AsyncAPI Specifications: Message contracts for domain and integration events
Webhook Specifications: JSON Schema for webhook payloads and callbacks
SDK Documentation: C# and JavaScript SDK usage with examples
Contract Tests: Automated tests for all producer/consumer contracts
Versioning Guide: Compatibility rules and migration procedures
Contract Changelog: History of contract changes per version
Integration Examples: Sample code for common integration scenarios
Contract Validation Pipeline: CI/CD integration for automated validation

Acceptance (done when)

Contract types are explained with examples of when to use each
Navigation to specifications is clear and organized by integration pattern
Versioning strategy is documented with compatibility rules and examples
Contract testing approach is explained with examples and CI/CD integration
Governance process is documented for contract changes and approvals
Shared contracts are documented (idempotency, correlation, errors)
Evolution guide explains how to add, change, and deprecate contracts
Quick reference enables fast navigation to specific contracts
Integration examples show end-to-end usage of contracts
Documentation complete with diagrams, code examples, and cross-references

Detailed Cycle Plan¶

CYCLE 1: Contract-First Development & Overview (~2,000 lines)¶

Topic 1: Contract-First Development Philosophy¶

What will be covered:

What is Contract-First Development?
Define contracts before implementation
Contracts are executable specifications
Implementation must satisfy contract
Tests validate contract compliance
Benefits: parallel development, clear interfaces, fewer integration bugs
Why Contract-First for ATP?
Multiple teams integrating with ATP (producers and consumers)
External partners need stable interfaces
Compliance requires documented, versioned contracts
Parallel development of services
Early validation of integration patterns
Contract-First vs Code-First
Contract-First: Contract → Implementation → Validation
Code-First: Implementation → Generated Contract → Hope it works
Trade-offs and when to use each
ATP's approach: Contract-first for external, code-first internal
ATP Contract Philosophy
Consumer-Driven: Design for consumer needs
Backward Compatible: Never break existing consumers
Versioned: All contracts have explicit versions
Testable: Automated contract validation
Documented: Self-documenting (OpenAPI, AsyncAPI, JSON Schema)
Published: Contracts available before implementation
Contract Development Workflow
Define contract (OpenAPI, AsyncAPI, JSON Schema)
Review with consumers and producers
Validate contract (linting, policy checks)
Generate code stubs (optional)
Implement against contract
Validate implementation matches contract
Publish contract to registry
Monitor contract usage and compatibility
Contract Validation
Syntax validation (YAML/JSON linting)
Schema validation (OpenAPI Spec, AsyncAPI Spec)
Breaking change detection
Policy compliance (naming conventions, security)
Contract tests (producer and consumer)
Contract Registry
Centralized storage for all contracts
Version history and changelog
Contract discovery and search
Dependency tracking (who uses which contracts)
Deprecation notices

Code Examples: - OpenAPI contract example - AsyncAPI contract example - JSON Schema webhook contract - Contract validation in CI pipeline - Contract test example

Diagrams: - Contract-first workflow - Contract development lifecycle - Contract validation flow - Contract registry architecture

Deliverables: - Contract-first development guide - Validation framework - Contract registry setup - CI/CD integration templates

Topic 2: ATP Contracts Overview¶

What will be covered:

Contract Categories in ATP

1. REST API Contracts - Synchronous HTTP APIs - OpenAPI 3.0 specifications - Request/response schemas - Authentication and authorization - Error responses

2. Message Contracts (Async) - Domain events (within bounded contexts) - Integration events (across contexts) - AsyncAPI specifications - Message routing and filtering - Schema registry integration

3. Webhook Contracts - Outbound notifications - JSON Schema definitions - Webhook security (signatures) - Retry and delivery guarantees

4. SDK Contracts - C# SDK for producers - JavaScript SDK for frontend - SDK versioning and compatibility - SDK documentation and examples

5. Shared Contracts - Idempotency patterns - Correlation ID propagation - Tenant context headers - Error response formats - Rate limiting contracts

Contract Landscape in ATP

Contracts
├── REST APIs
│   ├── Ingestion API (POST /audit-events)
│   ├── Query API (GET /audit-events)
│   ├── Policy API (CRUD policies)
│   └── Export API (POST /exports)
├── Message Contracts
│   ├── Domain Events (50+ events)
│   ├── Integration Events (20+ events)
│   └── Command Messages (if used)
├── Webhooks
│   ├── Event Notifications
│   ├── Export Completion
│   └── Policy Violations
├── SDKs
│   ├── C# SDK (NuGet)
│   ├── JavaScript SDK (npm)
│   └── Python SDK (pip) - future
└── Shared Contracts
    ├── Idempotency Headers
    ├── Correlation Context
    ├── Error Responses
    └── Rate Limit Headers

Integration Patterns
Synchronous: REST APIs for commands and queries
Asynchronous: Messages for events and background processing
Push Notifications: Webhooks for real-time updates
SDK Integration: Libraries for language-specific convenience
Contract Ownership Model
Ingestion Context: Owns ingestion API and AuditEventReceived event
Query Context: Owns query API and projection events
Policy Context: Owns policy API and policy events
Export Context: Owns export API and export events
Shared: Platform team owns shared contracts
Contract Dependencies
REST APIs depend on domain model (DTOs from aggregates)
Messages depend on domain events
Webhooks depend on integration events
SDKs depend on REST APIs and message contracts
Shared contracts used by all

Code Examples: - Contract namespace organization - OpenAPI specification structure - AsyncAPI specification structure - JSON Schema webhook example - SDK usage example

Diagrams: - Contract landscape architecture - Integration patterns overview - Contract ownership map - Contract dependencies

Deliverables: - Contracts overview guide - Contract categorization - Ownership model - Dependency matrix

CYCLE 2: Contract Types & API Design (~2,500 lines)¶

Topic 3: REST API Contracts Overview¶

What will be covered:

ATP REST APIs Catalog

Ingestion API - POST /api/v1/audit-events - Ingest single event - POST /api/v1/audit-events/batch - Batch ingestion - GET /api/v1/health - Health check - OpenAPI: rest-apis.md#ingestion-api

Query API - GET /api/v1/audit-events - List events with filters - GET /api/v1/audit-events/{id} - Get event by ID - POST /api/v1/audit-events/search - Advanced search - GET /api/v1/event-streams/{id} - Get event stream - OpenAPI: rest-apis.md#query-api

Policy API - POST /api/v1/policies - Create policy - GET /api/v1/policies - List policies - PUT /api/v1/policies/{id} - Update policy - DELETE /api/v1/policies/{id} - Delete policy - OpenAPI: rest-apis.md#policy-api

Export API - POST /api/v1/exports - Request export - GET /api/v1/exports/{id} - Get export status - GET /api/v1/exports/{id}/download - Download export - OpenAPI: rest-apis.md#export-api

RESTful Design Principles
Resource-oriented URLs
HTTP verbs semantics (GET, POST, PUT, DELETE)
Status codes (200, 201, 400, 401, 404, 500)
HATEOAS (optional, for discoverability)
Request/Response Patterns
Request headers (correlation, tenant, idempotency)
Request body (JSON, validation)
Response headers (rate limiting, pagination)
Response body (data, metadata, links)
Error responses (standard format)
Authentication & Authorization
Bearer token (OAuth 2.0, Azure AD)
API key (for service-to-service)
Tenant context resolution
RBAC enforcement
Pagination & Filtering
Pagination (offset/limit or cursor-based)
Filtering (query parameters)
Sorting (orderBy parameter)
Field selection (fields parameter)
Rate Limiting
Per-tenant rate limits
Rate limit headers (X-RateLimit-*)
429 Too Many Requests response
Retry-After header

Code Examples: - OpenAPI specification excerpt - Request/response examples (cURL) - Authentication header examples - Error response examples

Diagrams: - REST API architecture - Request/response flow - Authentication flow - Rate limiting mechanism

Deliverables: - REST API overview - API design guidelines - OpenAPI spec templates - Authentication guide

Topic 4: Message Contracts Overview¶

What will be covered:

ATP Message Catalog

Domain Events (Internal to Bounded Contexts) - Ingestion: AuditEventReceived, ValidationFailed - Storage: EventStreamCreated, EventStreamSealed - Classification: EventClassified, PIIDetected - Full catalog: message-schemas.md#domain-events

Integration Events (Cross-Context Communication) - Tenant: TenantOnboarded, TenantSuspended - Export: ExportRequested, ExportCompleted - Integrity: HashChainValidated, SignatureVerified - Full catalog: message-schemas.md#integration-events

Command Messages (If Used) - IngestAuditEvent, CreateExport, ApplyPolicy - Command vs Event distinction - Command routing and handling

Messaging Patterns
Publish/Subscribe: Broadcast to multiple consumers
Point-to-Point: Single consumer per message
Request/Reply: Synchronous-like over async (rare in ATP)
Event Streaming: Continuous event flow
Message Structure
Envelope: Metadata (EventId, Timestamp, TenantId, CorrelationId)
Payload: Business data specific to event type
Headers: Routing, filtering, security metadata
Message Routing
Azure Service Bus topics and subscriptions
Routing rules (content-based, topic-based)
Message filtering
Fan-out patterns
Message Schema Formats
JSON: Primary format (human-readable)
Protocol Buffers: Alternative (compact, typed)
Apache Avro: Alternative (schema evolution)
Format selection criteria
Schema Registry Integration
Centralized schema storage
Schema validation at publish/consume
Schema evolution tracking
Schema compatibility checking

Code Examples: - AsyncAPI specification excerpt - Message envelope structure - Domain event class (C#) - Integration event class (C#) - Service Bus configuration

Diagrams: - Message architecture - Pub/sub pattern - Message routing - Schema registry flow

Deliverables: - Message contracts overview - AsyncAPI spec templates - Message routing guide - Schema registry setup

CYCLE 3: Contract Testing & Versioning (~2,000 lines)¶

Topic 5: Contract Testing¶

What will be covered:

What is Contract Testing?
Verify producer and consumer agree on contract
Test contracts independently of full integration
Prevent breaking changes from reaching production
Faster feedback than end-to-end tests
Producer Contract Tests
Producer generates messages matching contract
Validate response schemas match OpenAPI
Validate message schemas match AsyncAPI
Run in producer's CI pipeline
Consumer Contract Tests
Consumer can handle messages per contract
Consumer expects specific contract version
Run in consumer's CI pipeline
Pact framework for consumer-driven contracts
Contract Compatibility Testing
Backward compatibility validation
Forward compatibility validation
Breaking change detection
Cross-version testing
REST API Contract Tests
Request validation (body, headers, parameters)
Response validation (status, body, headers)
Error response validation
Authentication and authorization testing
Message Contract Tests
Event schema validation (JSON Schema)
Message envelope validation
Required vs optional fields
Data type validation
Webhook Contract Tests
Webhook payload validation
Signature verification
Retry behavior testing
Callback response validation
Contract Test Automation
Tests run in CI/CD pipeline
Tests block deployment on failure
Test results published
Contract coverage metrics
Tools and Frameworks
Pact (consumer-driven contracts)
Spring Cloud Contract (JVM)
Postman/Newman (API testing)
JSON Schema validators
Custom test frameworks

Code Examples: - Producer contract test (C#, xUnit) - Consumer contract test (Pact) - REST API contract test (Postman) - Message contract test (JSON Schema) - CI pipeline with contract tests

Diagrams: - Contract testing flow - Producer/consumer test interaction - Pact broker architecture - CI/CD integration

Deliverables: - Contract testing guide - Test framework setup - Pact integration - CI/CD templates

Topic 6: Contract Versioning & Evolution¶

What will be covered:

Why Contract Versioning Matters
Multiple versions in production simultaneously
Consumer migration takes time
Zero-downtime upgrades required
Backward compatibility essential
Semantic Versioning for Contracts
MAJOR.MINOR.PATCH for contract versions
MAJOR: Breaking changes (incompatible)
MINOR: New features (backward compatible)
PATCH: Bug fixes, clarifications
REST API Versioning Strategies
URI Versioning: /api/v1/, /api/v2/ (ATP approach)
Header Versioning: Accept: application/vnd.atp.v1+json
Query Parameter: ?version=1 (not recommended)
ATP uses URI versioning for clarity
Message Versioning Strategies
Event Name Versioning: AuditEventReceivedV2
Schema Version Field: schemaVersion: "2.0"
Content Negotiation: Consumer specifies accepted versions
ATP uses schema version field
Compatibility Rules
Backward Compatible Changes (safe):
- Add optional fields
- Add new endpoints
- Add new event types
- Relax validation rules
Forward Compatible Changes (safe):
- Remove optional fields (if consumers ignore unknown)
- Deprecate endpoints (with notice)
Breaking Changes (requires new version):
- Remove required fields
- Change field types
- Rename fields
- Add required fields
- Tighten validation rules
Deprecation Process
Announce deprecation (minimum 6 months notice)
Mark as deprecated in contract (OpenAPI deprecated: true)
Provide migration guide
Monitor usage of deprecated contracts
Remove after sunset date
Contract Migration
Dual Publishing: Support v1 and v2 simultaneously
Adapter Pattern: Transform v1 to v2 internally
Consumer Migration: Gradual migration of consumers
Sunset Timeline: Remove old version after all migrated
Version Compatibility Matrix
Which producer versions work with which consumer versions
API version to message version mapping
SDK version compatibility
Support matrix (which versions are supported)

Code Examples: - Versioned API endpoints - Versioned message schemas - Deprecation annotations (OpenAPI) - Migration code examples - Compatibility test cases

Diagrams: - Versioning strategy - Deprecation timeline - Migration workflow - Compatibility matrix

Deliverables: - Versioning strategy guide - Compatibility rules - Deprecation process - Migration playbooks

CYCLE 4: Contract Governance & Best Practices (~1,500 lines)¶

Topic 7: Contract Governance¶

What will be covered:

Contract Ownership
Each context owns its contracts
Shared contracts owned by platform team
Clear ownership in contract metadata
Contract Change Process
Proposal (describe change and rationale)
Impact analysis (who's affected?)
Contract review (architects, affected teams)
Breaking change approval (if needed)
Implementation
Contract tests updated
Documentation updated
Publication and notification
Contract Review Guidelines
Naming conventions compliance
Schema design best practices
Backward compatibility check
Security review (sensitive data, authorization)
Performance impact assessment
Contract Approval Workflow
Non-breaking changes: Team lead approval
Breaking changes: Architecture review + affected teams approval
Shared contracts: Platform team + all consumers approval
Contract Documentation Requirements
Description of contract purpose
Usage examples (requests, responses, events)
Error scenarios and handling
Authentication and authorization
Rate limiting and quotas
Versioning and deprecation info
Contract Registry Governance
Who can publish contracts
Version immutability (published = locked)
Deprecation authority
Sunset enforcement
Compliance and Security Review
Data classification (what sensitivity data in contract)
GDPR compliance (personal data handling)
HIPAA compliance (PHI handling)
Security scanning (credential exposure, injection risks)

Code Examples: - Contract metadata (ownership, version) - Approval workflow (Azure DevOps) - Review checklist - Compliance annotations

Diagrams: - Contract change workflow - Approval process - Governance model - Review criteria

Deliverables: - Governance process guide - Review checklists - Approval templates - Compliance review procedures

Topic 8: Contract Best Practices¶

What will be covered:

REST API Design Best Practices
Resource naming (plural nouns)
HTTP verb usage (GET, POST, PUT, DELETE, PATCH)
Status code selection (2xx, 4xx, 5xx)
Pagination patterns (limit/offset or cursor)
Error response structure (consistent format)
Security (authentication, authorization, input validation)
Message Design Best Practices
Event naming (past tense, specific)
Event size (keep < 64KB for Service Bus)
Event granularity (one business fact per event)
Event enrichment vs minimal payload
Ordering and causation (CausationId)
Webhook Design Best Practices
Retry logic (exponential backoff)
Signature verification (HMAC)
Timeout configuration
Delivery confirmation
Error handling
Schema Design Best Practices
Use JSON Schema for validation
Required vs optional fields (minimize required)
Data types (string, number, boolean, object, array)
Enums for fixed values
Format annotations (date-time, email, uri)
Examples in schema
Versioning Best Practices
Start with v1, not v0
Avoid breaking changes
Use optional fields for extensions
Deprecate gracefully (6+ months notice)
Document all changes
Documentation Best Practices
Self-documenting contracts (OpenAPI, AsyncAPI)
Comprehensive descriptions
Usage examples for all endpoints/events
Error scenario documentation
Authentication instructions
Testing Best Practices
Contract tests for all contracts
Backward compatibility tests
Breaking change detection automated
Consumer-driven contract tests (Pact)
Security Best Practices
Never expose credentials in contracts
Validate all inputs
Sanitize outputs (no PII leakage)
Rate limiting on all APIs
Audit all contract usage
Performance Best Practices
Pagination for large result sets
Filtering server-side, not client-side
Caching headers (ETag, Cache-Control)
Compression (gzip, br)
Async for long-running operations
Common Anti-Patterns to Avoid
Exposing internal IDs in public APIs
Versioning in query parameters
Overly large payloads
Mutable events
Undocumented breaking changes
No versioning strategy
Missing error handling
Inconsistent naming conventions

Code Examples: - Best practice examples (good vs bad) - API design patterns - Message design patterns - Security patterns - Performance optimizations

Diagrams: - Best practices checklist - Anti-patterns to avoid - Design decision trees

Deliverables: - Best practices catalog - Anti-patterns guide - Design guidelines - Security checklist

Contract Documentation Index¶

REST API Contracts¶

→ REST APIs Specification - Complete OpenAPI specs for all HTTP endpoints
- Ingestion API (event publishing) - Query API (event retrieval and search) - Policy API (policy management) - Export API (eDiscovery and compliance)

Message Contracts¶

→ Message Schemas - AsyncAPI specs for all events
- Domain Events (50+ events) - Integration Events (20+ events) - Command Messages (if applicable) - Event envelope structure

Webhook Contracts¶

→ Webhooks Specification - Outbound notification contracts
- Event notification webhooks - Export completion webhooks - Policy violation webhooks - Webhook security and retry

Shared Contracts¶

→ Idempotency Contracts - Idempotency patterns
- Idempotency-Key header - Deduplication strategies - Idempotency in REST and messaging

Integration Scenarios¶

Scenario 1: Producing Audit Events¶

Use Case: Microservice wants to emit audit events to ATP

Contracts Needed: 1. REST API: POST /api/v1/audit-events 2. SDK: C# SDK IAuditEventPublisher 3. Shared: Idempotency-Key header 4. Shared: Correlation-Id header

Documentation: → REST APIs: Ingestion
→ SDK Usage
→ Idempotency

Scenario 2: Querying Audit Events¶

Use Case: Application needs to search audit events

Contracts Needed: 1. REST API: GET /api/v1/audit-events (list/filter) 2. REST API: POST /api/v1/audit-events/search (advanced search) 3. Shared: Pagination contracts 4. Shared: Filtering contracts

Documentation: → REST APIs: Query
→ Query Examples

Scenario 3: Receiving Event Notifications¶

Use Case: External system wants real-time notifications

Contracts Needed: 1. Webhook: Event notification webhook 2. Shared: Webhook signature verification 3. Message: Integration event schemas

Documentation: → Webhooks
→ Message Schemas: Integration Events

Scenario 4: Exporting for eDiscovery¶

Use Case: Legal team needs export for compliance

Contracts Needed: 1. REST API: POST /api/v1/exports (request export) 2. REST API: GET /api/v1/exports/{id} (check status) 3. Webhook: Export completion notification 4. Message: ExportCompleted event

Documentation: → REST APIs: Export
→ Webhooks: Export Completion
→ Export Guide

Contract Quick Reference¶

REST API Endpoints Summary¶

Endpoint	Method	Purpose	Auth	Rate Limit
`/api/v1/audit-events`	POST	Ingest event	Bearer	1000/min
`/api/v1/audit-events`	GET	List events	Bearer	100/min
`/api/v1/audit-events/search`	POST	Search events	Bearer	50/min
`/api/v1/audit-events/{id}`	GET	Get by ID	Bearer	100/min
`/api/v1/event-streams/{id}`	GET	Get stream	Bearer	100/min
`/api/v1/policies`	POST	Create policy	Bearer	10/min
`/api/v1/policies`	GET	List policies	Bearer	50/min
`/api/v1/exports`	POST	Request export	Bearer	5/min
`/api/v1/exports/{id}`	GET	Export status	Bearer	20/min

Full specs: rest-apis.md

Domain Events Summary¶

Event	Producer	Consumers	Purpose
AuditEventReceived	Ingestion	Storage, Classification	Event ingested
EventStreamCreated	Storage	Query, Integrity	Stream started
EventStreamSealed	Storage	Integrity, Export	Stream finalized
EventClassified	Classification	Query, Retention	Classification applied
RetentionApplied	Retention	Query	Retention set
TenantOnboarded	Tenant	All Contexts	New tenant
ExportCompleted	Export	Webhook, SIEM	Export ready

Full catalog: events-catalog.md

Integration Events Summary¶

Event	Producer Context	Consumer Context(s)	Purpose
TenantOnboarded	Policy	All	New tenant setup
ExportRequested	Export	Storage, Query	Start export
IntegrityVerified	Integrity	Query, Export	Verification passed

Full schemas: message-schemas.md

Contract Standards¶

Shared Headers (All Contracts)¶

Header	Required	Description	Example
`X-Tenant-Id`	Yes	Tenant context	`tenant-abc-123`
`X-Correlation-Id`	Yes	Request correlation	`corr-abc-123-def-456`
`Idempotency-Key`	For writes	Duplicate detection	`idem-xyz-789`
`Authorization`	Yes	Bearer token	`Bearer eyJ0eXAi...`
`Content-Type`	Yes	Media type	`application/json`
`User-Agent`	Recommended	Client identification	`ATP-SDK/1.2.3`

Details: shared/idempotency.md

Error Response Format (All REST APIs)¶

{
  "error": {
    "code": "VALIDATION_FAILED",
    "message": "The request contains invalid data",
    "details": [
      {
        "field": "timestamp",
        "issue": "Timestamp cannot be in the future",
        "value": "2025-01-01T00:00:00Z"
      }
    ],
    "traceId": "00-abc123...-def456...-01",
    "timestamp": "2024-10-30T10:30:00Z"
  }
}

Specification: rest-apis.md#error-responses

Summary & Implementation Plan¶

Implementation Phases¶

Phase 1: Foundation (Cycle 1) - 1 week - Contract-first philosophy - Contracts overview

Phase 2: Specifications (Cycle 2) - 1 week - REST API and message contract overviews

Phase 3: Validation (Cycle 3) - 1 week - Contract testing and versioning

Phase 4: Governance (Cycle 4) - 1 week - Contract governance and best practices

Success Metrics¶

Navigation Speed: Find relevant contract in < 30 seconds
Integration Time: New integrations complete in < 1 day using contracts
Breaking Changes: Zero unplanned breaking changes
Contract Coverage: 100% of APIs/events have contracts
Test Coverage: 100% of contracts have automated tests
Documentation: 100% of contracts documented with examples

Ownership & Maintenance¶

Integration Engineers: Cycles 1-2, contract design
QA Engineers: Cycle 3, contract testing
Architects: Cycle 4, governance and standards
All Teams: Contract usage and feedback

Domain Model¶

→ Domain Overview - Domain layer introduction
→ Ubiquitous Language - Shared vocabulary
→ Aggregates & Entities - Domain model
→ Events Catalog - All events

Implementation¶

→ Messaging Implementation - Event bus
→ Outbox/Inbox Pattern - Reliable messaging
→ Persistence - Data access

Integration Guides¶

→ Producing Audit Events - How to publish events
→ Querying Audit Logs - How to query events
→ Export and eDiscovery - How to export

SDK Documentation¶

→ C# SDK - .NET integration
→ JavaScript SDK - Frontend integration
→ SDK Examples - Sample code

Document Status: ✅ Plan Approved - Ready for Content Generation

Target Start Date: Q2 2025

Expected Completion: Q2 2025 (1 month)

Owner: Integration Engineering Team

Last Updated: 2024-10-30

Integration Contracts - Audit Trail Platform (ATP)¶

📋 Documentation Generation Plan¶

Purpose & Scope¶

Detailed Cycle Plan¶

CYCLE 1: Contract-First Development & Overview (~2,000 lines)¶

Topic 1: Contract-First Development Philosophy¶

Topic 2: ATP Contracts Overview¶

CYCLE 2: Contract Types & API Design (~2,500 lines)¶

Topic 3: REST API Contracts Overview¶

Topic 4: Message Contracts Overview¶

CYCLE 3: Contract Testing & Versioning (~2,000 lines)¶

Topic 5: Contract Testing¶

Topic 6: Contract Versioning & Evolution¶

CYCLE 4: Contract Governance & Best Practices (~1,500 lines)¶

Topic 7: Contract Governance¶

Topic 8: Contract Best Practices¶

Contract Documentation Index¶

REST API Contracts¶

Message Contracts¶

Webhook Contracts¶

Shared Contracts¶

Integration Scenarios¶

Scenario 1: Producing Audit Events¶

Scenario 2: Querying Audit Events¶

Scenario 3: Receiving Event Notifications¶

Scenario 4: Exporting for eDiscovery¶

Contract Quick Reference¶

REST API Endpoints Summary¶

Domain Events Summary¶

Integration Events Summary¶

Contract Standards¶

Shared Headers (All Contracts)¶

Error Response Format (All REST APIs)¶

Summary & Implementation Plan¶

Implementation Phases¶

Success Metrics¶

Ownership & Maintenance¶

Related Documentation¶

Domain Model¶

Implementation¶

Integration Guides¶

SDK Documentation¶