> ## Documentation Index
> Fetch the complete documentation index at: https://docs.getversive.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Update study quotas

> Replace the study-level quota configuration

Replaces the study's quota configuration. Modes are mutually exclusive: send the full configuration for the mode you want, and any previous configuration is discarded. Question quotas are not affected.

<ParamField path="id" type="string" required>The study ID.</ParamField>

<ParamField body="mode" type="string" required>`off`, `fixed`, or `url_param`.</ParamField>

<ParamField body="fixed_limit" type="integer">
  Required in `fixed` mode, not allowed otherwise. `0` closes the study to new participants.
</ParamField>

<ParamField body="param_name" type="string">
  Required in `url_param` mode, not allowed otherwise. Letters, digits, underscores, and hyphens only; up to 64 characters.
</ParamField>

<ParamField body="buckets" type="array">
  Required in `url_param` mode, not allowed otherwise. One `{ value, limit }` per link value, up to 50, with unique values. Matching is exact and case-sensitive. A `limit` of `0` closes that value.
</ParamField>

<ParamField body="unmatched_param_policy" type="string" default="allow">
  `allow` lets in participants whose link has no matching value (they don't count toward any bucket); `reject` turns them away.
</ParamField>

### Response

The saved configuration, same shape as [Get study quotas](/api-reference/quotas/get-study-quotas).

<Tip>
  To check what a given link would do before sharing it, `POST /studies/{id}/quotas/evaluate` with `{ "entry_params": { "group": "1" } }` returns `{ allowed, reason, bucket }` without recording anything.
</Tip>

<RequestExample>
  ```bash cURL theme={null}
  curl -X PUT https://api.getversive.com/api/v1/studies/9b2f7c1e-4a4b-4f6e-9a1d-1c2d3e4f5a6b/quotas \
    -H "Authorization: Bearer $VERSIVE_API_KEY" \
    -H "Content-Type: application/json" \
    -d '{
      "mode": "url_param",
      "param_name": "group",
      "buckets": [
        { "value": "1", "limit": 50 },
        { "value": "2", "limit": 50 }
      ],
      "unmatched_param_policy": "reject"
    }'
  ```
</RequestExample>