429 Too Many Requests during large dataset pagination

Question

Trello REST API
When retrieving a large volume of cards from a single board, the API requires the use of the limit parameter to bound result sets and prevent payload timeouts. To retrieve the full dataset, a client must execute multiple sequential requests.
There is a conflict between the need for high-frequency pagination to clear a large queue and the API's rate-limiting thresholds. As the number of requests increases to handle deep pagination, the risk of hitting the rate limit grows, potentially interrupting the data synchronization process.

What is the maximum allowable value for the limit parameter before the API reverts to a default page size?
How can a client optimize the fields parameter to reduce payload size and mitigate the frequency of requests needed for large boards?

Tasadduq Burney · Answer

Answer
The Trello REST API accepts a limit parameter whose maximum allowed value is 1000. Supplying a value greater than 1000 causes the API to ignore the supplied value and fall back to the default page size of 1000 items.
Confirmed fact
According to the official Trello API documentation, the limit argument is validated to be in the range 1‑1000 inclusive; any out‑of‑range value is treated as the default limit.
Likely explanation
When a client requests a page size larger than the allowed maximum, the server silently resets the limit to the default. This means that trying to “cheat” the rate limit by asking for a huge page does not reduce the number of round‑trips; the API will still return at most 1000 cards per request.
Optimizing the fields parameter
To reduce payload size and therefore the number of requests needed to pull a large board, request only the fields your application actually uses. The fields query parameter accepts a comma‑separated list of card attributes.

Identify the minimal set of fields required (e.g., id,name,desc,due,labels,shortUrl).
Include that list in the request: GET /1/boards/{boardId}/cards?limit=1000&fields=id,name,desc,due,labels,shortUrl.
If you only need identifiers, you can further reduce the payload to fields=id,name.
Combine field selection with a filter to limit the dataset, e.g., filter=open to exclude archived cards.

Putting it together – recommended request pattern
GET https://api.trello.com/1/boards/{boardId}/cards?
    limit=1000&
    fields=id,name,desc,due,labels,shortUrl&
    filter=open&
    key={yourKey}&token={yourToken}

This yields the maximum possible page size while keeping each response as small as practicable.
Mitigating 429 responses

Honor the Retry-After header (or X-RateLimit-Reset) returned with any 429 and wait that many seconds before retrying.
Implement exponential back‑off if successive 429s occur.
Monitor the number of requests per interval and ensure it stays below the documented limit for your API key/token (typically 100 requests per 10 seconds for a standard key).

Missing diagnostic detail
To fine‑tune the delay between requests, I need to know the exact rate‑limit quota applied to your API key/token (requests per interval). If this differs from the default 100/10 s, the recommended back‑off interval would change.

429 Too Many Requests during large dataset pagination

Trello REST API

1 answer

Answer

Confirmed fact

Likely explanation

Optimizing the `fields` parameter

Putting it together – recommended request pattern

Mitigating 429 responses

Missing diagnostic detail

Your perspective belongs here.

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