The Formstack API allows users and 3rd party application to access resources programmatically. This API conforms to REST principals.
Formstack API V2025 Documentation
API Methods
A list of all api methods (exposed as REST resources) can be found here. If you would like to leverage your own AI tools, feel free to point them to our LLMs.txt file.
Request Formats
The Formstack API accepts two request data types: HTTP url encoded query parameters and JSON. By default, we expect HTTP url encoded query parameters. To use JSON, simply change the Content-Type header in your request to be "Content-Type: application/json" and put the JSON in the body of the request.
Response Formats
The Formstack API V2025 returns responses in JSON format only.
https://www.formstack.com/api/v2025/forms
https://www.formstack.com/api/v2025/forms/12334/submissionsObtaining an API Token
All of our API calls require authentication. The V2025 API uses Personal Access Tokens for authentication. These tokens provide secure, token-based access to your Formstack account.
For detailed information on creating and managing Personal Access Tokens, please visit: Formstack Personal Access Tokens
Personal Access Tokens are tied to a Formstack user and follow Formstack (in-app) user permissions.
Authentication
Once you have a Personal Access Token, you can make authenticated API calls. To do this, include the access token in the HTTP Authorization header:
Authorization: Bearer fs_pat_<your-personal-access-token>Personal Access Tokens are prefixed with fs_pat_ for easy identification and security.
That access token is similarly used on the Try It Out feature on this website. Input Bearer fs_pat_<your-personal-access-token> into the Authorization field of the Try It Out feature on any of the APIs.
Rate Limits
To prevent abuse, the Formstack V2025 API implements daily rate limiting per access token. The specific limits vary based on your account plan type. When you exceed your daily quota, you'll receive a 429 Too Many Requests error.
Rate limit information is tracked and logged for each API call, with quotas resetting daily at midnight.
Status Codes
The Formstack API uses standard HTTP status codes.
| Code | Description |
|---|---|
| 200 | OK - The request was handled without any errors |
| 201 | Created - A new resource was created |
| 400 | Bad Request - The request URI was invalid |
| 401 | Unauthorized - Valid authentication credentials were not supplied |
| 403 | Forbidden - The current user does not have access to this method |
| 404 | Not Found - The resource requested could not be found |
| 405 | Method Not Allowed - The requested method does not exist |
| 415 | Unsupported Media Type - A valid media type (JSON, XML, HTTP URL encoded) was not used |
| 429 | Too Many Requests - The current user has hit the daily rate limit |
| 500 | Internal Server Error - An error occurred while processing the request |
| 503 | Service Unavailable - The service is temporarily unavailable (maintenance mode) |