post https://example.com/v1/submit
Creates a new submission for a Form.
POST /api/v1/submit
Host: formstack.com
api_key=[[app:api_key]]&id=1234&field_12345=john&field_12346=smith
field_x
For this parameter, x must contain the id of the field whose value should be set. For example, a field with the ID of 12345 would mean the parameter is field_12345.
Fields with Sub-fields
For fields that have multiple sub-fields, we store them raw as one field, separated by a key and return character. See examples below:
Name stored as "first = john\nlast = smith" in Formstack would be submitted as first%20%3D%20john%5Cnlast%20%3D%20smith
File Uploads
Files can be uploaded via the API in a similar way text values are passed, except that file contents must be base64 encoded before transfer. You can also optionally specify the file name to use by prepending it to the data along with a semicolon.
POST /api/v1/submit
Host: formstack.com
api_key=[[app:api_key]]&id=111&field_1001=hello.txt;SGVsbG8hIFRoYW5rcyBmb3IgdXNpbmcgdGhlIEZvcm1TcHJpbmcgQVBJLg==