01
Describe Your Product
Explain your SaaS, mobile app, AI product, backend service, payment platform, marketplace, or internal tool.
{ API_DOCS }
AI API Documentation Generator
Generate professional API documentation in minutes with AI. Create clear, developer-friendly REST API documentation, endpoint references, request/response examples, authentication guides, and OpenAPI-ready documentation before writing production code.
// free to generate
GET /api/v1/users
Authorization: Bearer {token}
Response
200 OK
{ "users": [...]
"total": 142,
"page": 1 }
FUNDAMENTALS
What is an API?
An API (Application Programming Interface) is a set of rules that allows different software applications to communicate with each other. APIs define how requests are made, what data is sent, and what responses to expect — acting as the contract between a client and a server.
Client
→↓
API Request
→↓
Server
→↓
API Response
→↓
Client
Every time you use an app that fetches data, makes a payment, or sends a notification — an API is working behind the scenes.
What is API Documentation?
API documentation is a structured guide explaining how developers interact with an API. It documents every endpoint, request, response, authentication method, parameters, headers, error codes, and usage examples. Good API documentation answers:
What does this API do?
How do I authenticate?
Which endpoints are available?
What parameters are required?
What responses should I expect?
Which errors can occur?
How do I integrate this API?
Instead of developers guessing how an API works, they receive clear documentation from day one.
Why Use an AI API Documentation Generator?
Writing API documentation manually is repetitive and time-consuming.
PLANNR automatically generates structured API documentation based on your product requirements, backend architecture, and API design. Instead of maintaining dozens of documentation pages manually, you receive consistent, professional documentation ready for developers.
What PLANNR Generates
Every API documentation includes:
GETAPI Overview
POSTAuthentication Guide
GETBase URL
GETEndpoint Reference
GETHTTP Methods
POSTRequest Parameters
GETPath Parameters
GETQuery Parameters
POSTRequest Body
GETResponse Examples
GETStatus Codes
GETError Messages
POSTValidation Rules
GETRate Limits
GETPagination
POSTWebhook Documentation
GETSDK & Integration Notes
GETSecurity Best Practices
POSTExample Requests
PROCESS
How It Works
02
Answer Smart Questions
PLANNR understands users, authentication, resources, endpoints, permissions, integrations, data models, and business logic.
03
Generate API Documentation
Receive complete API documentation automatically. Every endpoint documented consistently with requests, responses, examples, and implementation notes.
04
Share with Developers
Export and use with internal engineering teams, frontend developers, backend developers, third-party integrators, and AI coding tools like Cursor, Claude Code, Lovable, Bolt, Windsurf, and Replit.
What Makes Great API Documentation?
Professional API documentation should include:
- Clear endpoint descriptions
- Authentication instructions
- Request examples
- Response examples
- Error handling
- Rate limits
- Pagination
- Versioning
- Webhooks
- Security guidance
- SDK examples
- Integration tutorials
$ plannr --check-docs
✓ easy to navigate
✓ consistent across endpoints
✓ developer-friendly
✓ example-driven
✓ secure
✓ version-aware
✓ ready for collaboration
USE CASES
Generate Documentation For
INTERNAL
Internal APIsMobile App BackendsCRM APIsERP APIs
PUBLIC
Public APIsREST APIsAI APIs
PLATFORM
SaaS PlatformsPayment APIsAuthentication APIsEnterprise Services
ARCHITECTURE
MicroservicesWebhook APIs
Manual API Documentation vs AI API Documentation
Manual Documentation
PLANNRHours of writing
Minutes
Easy to miss endpoints
Complete structured documentation
Inconsistent formatting
Standardized output
Difficult to maintain
Organized and export-ready
Limited examples
Automatic request & response examples
Repetitive updates
AI-assisted documentation generation
Frequently Asked Questions
API documentation explains how developers can interact with an API, including authentication, endpoints, parameters, request formats, response formats, and error handling.
API documentation helps developers understand, integrate, test, and maintain APIs without needing direct support from the API creators.
A complete API documentation should include: API overview, Authentication, Endpoints, Parameters, Request examples, Response examples, Error codes, Rate limits, SDK references, and Integration guides.
Good API documentation starts by identifying every endpoint, documenting request and response formats, explaining authentication, providing examples, and describing common errors. PLANNR automates this entire workflow using AI.
API documentation is commonly written by backend developers, technical writers, software architects, or platform engineers. With PLANNR, AI generates the initial documentation, significantly reducing manual work.
Yes. AI can generate structured API documentation based on your backend architecture and endpoint definitions. PLANNR creates organized, developer-friendly documentation that is easier to understand and maintain.
High-quality API documentation is easy to read, searchable, well organized, rich with examples, consistent across endpoints, and continuously updated.
PLANNR generates export-ready API documentation that can be reused as a template for future projects and APIs.
curl -X POST https://api.plannr.ai/generate \
-H "Content-Type: application/json" \
-d '{"type": "api-docs", "project": "your-idea"}'Build Better APIs with Better Documentation
Well-documented APIs are easier to develop, easier to integrate, and easier to maintain. Generate professional API documentation before development starts and give your developers everything they need to build with confidence.