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429 response for refreshing access tokens

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My application is using the OAuth2 Authorization Code Flow, and running into 429 errors when refreshing the access tokens.


I have been refreshing tokens every hour, just since our system runs hourly tasks and daily tasks, and the access tokens are said to last 24 hours. Are we really not able to refresh every hour? Also, we are currently in a trial mode with our constant contact api and only have a few clients (websites) using our application to send their customers' emails to Constant Contact, and we plan to expand quite a bit.

0 Votes

Hello JoeD576,


Thank you for reaching out to Constant Contact API Developer Support. My team is here to assist outside software developers with questions about building into Constant Contact's API.


As Constant Contact rate limits the token endpoint, it is recommended that you only send in the refresh token to obtain a new access token when your existing access token is expired or about to expire. You are correct in that our access tokens have a maximum life of 24 hours. A 429 response indicates that the rate limit has been reached at the token endpoint. For more information on our access and refresh tokens, I am including documentation below.


OAuth 2.0 Overview:


Please have a look and let us know if you have any other questions!



John B.
API Support Specialist
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