Three-legged OAuth

SignNow API allows third-party applications to access users’ resources in SignNow account. All they need is to get a token with the authorization_code grant type.


  • Obtain an authorization code
  • Request a bearer token using the authorization code

SignNow generates an authorization code automatically from your client ID. Once it’s done, SignNow redirects the user to the specified URI with authorization code passed as a query parameter.


▶ Embed a link to SignNow Auth page with specific query parameters into your app/crm/website

Required query parameters: client_id, redirect_uri, response_type=code

Link to embed:{CLIENT_ID}&response_type=code&redirect_uri={YOUR_REDIRECT_URI}

Example: link to get the authorization code

▶ Follow the link
▶ Log in to SignNow (thus authorizing your app at SignNow)
▶ Click Grant access to SignNow
▶ The redirect_uri opens, this time with an authorization code generated as query parameter: retrieve authorization code from the URI

Example: redirect URI with an authorization code


▶ Use the authorization code to get a bearer access token with grant type authorization_code

curl -X POST '' \
-H 'Authorization: Basic {{basic_token}}' \
-H 'Content-Type: multipart/form-data;' \
-F 'grant_type=authorization_code' \
-F 'scope=*' \
-F 'code={{authorization_code}}'

Here is an example of JSON you get in response:

  "expires_in": "1584793649",
  "token_type": "bearer",
  "access_token": "4f3c0ce3f667fd20418fe866b29cb51bdd7f86d997a36364d65f7ac02071aaa4",
  "refresh_token": "5c10fbb9b0e6056a018c6470e3015448711060043d620efdb47c4bbad9531c34",
  "scope": "*",
  "last_login": 1