# Darwin Microservice Patterns > Microservice technical patterns for infrastructure and API design. Use when planning service changes, reviewing API contracts, or evaluating deployment strategies. Use when this capability is needed. - Skill: `tomevault-io/darwin-microservice-patterns` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/darwin-microservice-patterns` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/darwin-microservice-patterns/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Integrations & APIs - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/darwin-microservice-patterns --- # Microservice Technical Patterns ## Deployment & Independence - **Independently deployable**: Each service MUST deploy without coordinating with others. If a plan requires simultaneous deployment, redesign with backward-compatible contracts first. - **Feature flags over deploy coordination**: Use feature flags for progressive enablement rather than synchronized rollouts. ## API & Data Contracts - **Backward-compatible API changes**: Always additive. New fields are optional. Old fields never removed in the same release. - **API versioning**: If breaking changes are unavoidable, version the API (`/v1/`, `/v2/`). - **API contracts first**: Specify the contract (REST endpoint, event schema) before implementation details. - **Database schema independence**: Each service owns its data store. No shared databases. Migrations must be backward-compatible. ## Resilience - **Circuit breakers**: Any inter-service call should have timeout + retry + fallback. Flag plans missing resilience patterns. - **Idempotency**: Any state-modifying operation must be safe to retry. Specify how duplicate calls are handled. - **Health endpoints**: Every service must expose `/health` (liveness) and `/ready` (readiness) with meaningful checks. ## Operational Hygiene - **Observability**: Plans must include how changes will be monitored (metrics, logs, alerts). - **Configuration via environment**: No hardcoded URLs, credentials, or feature flags in code. Everything via env vars or ConfigMaps. - **Stateless services**: Flag any in-process state that breaks horizontal scaling (caches without TTL, sessions, in-memory queues). Externalize to Redis/DB. --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/the-darwin-project) — claim your Tome and manage your conversions.