---
title: "Update an environment variable"
method: PUT
path: "/v1/variables/{key}"
tags: ["Environment variables"]
---

# Update an environment variable

`PUT /v1/variables/{key}`

Updates an environment variable. Uses the "key" field as the ID for updating. Only updates value, locked, and secret properties. Once a value is set to secret, it cannot be unset.

## Path parameters

- `key` string, required — The key of the environment variable (this value cannot be changed).

## Headers

- `x-checkly-account` string, uuid — Your Checkly account ID, you can find it at https://app.checklyhq.com/settings/account/general

## Request body

- EnvironmentVariablesV1UpdateRequest
  - `key` string — The key of the environment variable (this value cannot be changed).
  - `value` string, required — The value of the environment variable.
  - `locked` boolean — Used only in the UI to hide the value like a password.
  - `secret` boolean — Set an environment variable as secret. Once set, its value cannot be unlocked.

## Response `200`

Successful

- EnvironmentVariablesV1MutationResponse
  - `key` string, required — The key of the environment variable (this value cannot be changed).
  - `value` string, required — The submitted value of the environment variable.
  - `locked` boolean, required — Used only in the UI to hide the value like a password.
  - `secret` boolean, required — Whether the environment variable is stored as a secret.

## Other responses

- `400` — Bad Request
- `401` — Unauthorized
- `403` — Forbidden
- `404` — Not Found
- `429` — Too Many Requests

## Changes

- **2026-08-12** `87d29dc7b4fe` — 5 breaking, 2 warning, 17 info
  - request body became required
  - for the `path` request parameter `key`, the minLength was increased from `0` to `1`
  - for the `header` request parameter `x-checkly-account`, the type/format was changed from `string`/`` to `string`/`uuid`
  - the `key` request property's minLength was increased from `0` to `1`
  - …20 more

[Change history](https://skmtc.dev/checklyhq/apis/checkly-public-api/changes/v1/variables/:key/put.md)

---

[API](https://skmtc.dev/checklyhq/apis/checkly-public-api.md) · [All operations](https://skmtc.dev/checklyhq/apis/checkly-public-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/checklyhq/checkly-public-api/revisions/87d29dc7b4fe/schema)