Welcome to SingleFile
Welcome to the SingleFile API — the fastest way to automate business entity formation, EIN filing, document management, and annual report compliance across all U.S. jurisdictions.
What You Can Do
Incorporate LLCs, Corporations, and more in any U.S. state — programmatically.
Obtain federal Employer Identification Numbers directly through the API.
Upload, search, and download formation documents and compliance records.
Stay in good standing with automated annual report filings across jurisdictions.
Getting Started in 4 Steps
┌──────────────┐ ┌──────────────┐ ┌──────────────┐ ┌──────────────┐
│ 1. Get Your │ │ 2. Get a │ │ 3. Make Your │ │ 4. Build │
│ Credentials │───>│ Bearer Token │───>│ First Call │───>│ Workflows │
└──────────────┘ └──────────────┘ └──────────────┘ └──────────────┘
SingleFile POST /o/token/ GET /entities Formation,
provides your with client_id to verify EIN, Annual
client_id & & client_secret everything works Reports & more
client_secretNew here? Jump straight to the Quick Start to make your first API call in under 5 minutes.
Environments
| Environment | Base URL | Purpose |
|---|---|---|
| Sandbox | https://api.demo.singlefile.io/external-api/v1/ | Development & testing — no real filings |
| Production | https://api.singlefile.io/external-api/v1/ | Live filings with state authorities |
Always develop and test against the Sandbox environment first. Sandbox requests behave identically to production but do not submit real filings.
Explore the Docs
Fundamentals
OAuth 2.0 client credentials flow with auto-refresh patterns
Get a token and make your first API call in minutes
Headers, response format, pagination, rate limits & conventions
Receive real-time notifications for order status changes
Workflow Guides
End-to-end guide for forming LLCs, Corps, and more
Automate federal tax ID applications
Search, download, and organize compliance documents
Maintain good standing with automated annual filings
Need Help?
Updated 24 days ago