# December 2, 2024 

** The December 2, 2024 Karbon API release adds compressed responses and introduces API rate limiting **
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## Compressed API responses
The Karbon API can now compress response payloads - this often significantly reduces the size of the transmitted response and the total time taken to complete the request.

In order to specify the response should be compressed, the `Accept-Encoding` HTTP header should include `gzip`, e.g. `Accept-Encoding: deflate, gzip`.
The response will then include the HTTP header `Content-Encoding: gzip` which indicates the payload is compressed using the `gzip` compression scheme.

As an example:
* A request to the `/v3/WorkItems` endpoint returns an uncompressed payload of *768kb* and takes *~1500ms*.
* With the `Accept-Encoding` header set to `gzip`, the response is compressed to *56kb* and takes *~650ms*.

Please note that actual compressed payload sizes and response durations will differ depending on factors such as the compressibility of the data and network speed.

## API Rate Limiting
The Karbon API now enforces a limit on the number of requests that can be made per minute.
When the rate limit is hit, the HTTP `429` response code is returned along with a `Retry-After` response header that specifies a delay in seconds before a request can be reattempted.

We recommend API users keep to a maximum of 120 requests per minute (2 requests per second) and implement handling of HTTP `429` response codes.

The limit is applies to the combination of the Karbon account and API application, for example:
* an API application connected to 10 different Karbon accounts
* for one of the accounts, the API application makes 600 requests per minute and is rate limited
* for each of the other 9 accounts the request volume is 90 requests per minute no rate limiting is applied