LinkedIn accepts only POST for access and refresh token requests after June 30, 2023

What changed

LinkedIn repeated this reminder in its March, April, May and June 2023 changelog sections. After June 30, 2023 the GET method on the /accessToken endpoint returns a 400 error. The March 2023 section is the earliest of those reminders on the 2023 archive page; whether it was announced earlier is not stated there.

What it means

Token exchange and refresh calls made with GET /accessToken return a 400 error after June 30, 2023.

Who is affected

Developers of any app that connects LinkedIn accounts through OAuth, including scheduling tools.

What to do by 30 Jun 2023

Send access token and refresh token requests with POST to /accessToken, header Content-Type set to x-www-form-urlencoded, and all parameters in the request body.