# Flask API Design > Building clean, RESTful APIs with Marshmallow for serialization and OpenAPI documentation. Use when this capability is needed. - Skill: `tomevault-io/flask-api-design` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/flask-api-design` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/flask-api-design/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Docs & Writing - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/flask-api-design --- # Flask API Design APIs should be self-documenting, consistent, and easy to consume. ## Serialization (Marshmallow) - **Schemas**: Transforming complex objects to/from primitive Python types. - **Validation**: Enforcing data constraints at the API layer. ## RESTful Routing - **Nouns not Verbs**: `/users/1` instead of `/getUser/1`. - **HTTP Methods**: GET (read), POST (create), PUT/PATCH (update), DELETE (remove). ## Documentation Use **Flask-Smorest** or **Flasgger** to automatically generate Swagger/OpenAPI UI for your endpoints. ## Best Practices - **Status Codes**: Return appropriate codes (e.g., `201 Created`, `404 Not Found`, `422 Unprocessable Entity`). - **Versioning**: Prefix routes with `/api/v1/`. --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/jcorpac) — claim your Tome and manage your conversions.