Is there any way of retrieving all records from a data extension via REST API for Marketing Cloud?

Question

I want to retrieve all contacts from a specific data extension via REST API but I don't find any documentation to do that.

Is there any way of retrieving all records from a data extension via REST API for Marketing Cloud?

Answer 1

There is an undocumented endpoint for getting records from a Data Extension using REST, with a filter defined by request parameters to the endpoint:

GET /data/v1/customobjectdata/key/YOURDEEXTERNALKEY/rowset?$filter=emailAddress%20eq%20'test@example.com' HTTP/1.1
Host: YOURTENANT.rest.marketingcloudapis.com
Authorization: Bearer YOURAUTHTOKEN
Content-Type: application/json
User-Agent: PostmanRuntime/7.17.1
Accept: */*
Cache-Control: no-cache
Host: YOURTENANT.rest.marketingcloudapis.com
Accept-Encoding: gzip, deflate
Connection: keep-alive
cache-control: no-cache

This is provided with NO GUARANTEES, and can be taken down or altered by Salesforce without any notice. I will not recommend using undocumented features in production context.

As to your question:

I want to retrieve all contacts from a specific data extension

This is doomed to fail, as you potentially don't have any control of the number of records in a given data extension. Remember that your API request might time-out, or return such a huge amount of data, that generating a response will not be feasible. I will advise against a solution which relies on pulling ALL records from a data extension. You would be better off (while building a more robust solution) using Data Extension Extract in Automation Studio.