Save or clear workspace custom CSS

Saves or clears the workspace’s shared survey CSS. customCss replaces both fields; null clears all of it. The source is processed by the same processor every save path uses: constructs it removes come back as top-level warnings, and CSS it rejects is a 422 that leaves the saved CSS in effect. The replaced value becomes previous, the one recoverable revision — restore it by sending its source back. Unchanged source writes nothing.

Workspace CSS reaches every survey in the workspace, so writing it is narrower than writing a survey: organization owners and managers for signed-in users (session or OAuth), and a manage grant on this workspace for API keys — a Read & write grant is refused with 403. On Formbricks Cloud, adding or editing needs the Scale plan (403 custom_css_plan_required); clearing never does. Successful changes refresh the cached configuration the SDKs receive (they pick it up on their next configuration fetch). Saves that add or edit CSS count against a custom CSS budget of 60 per minute per user or API key, shared with custom CSS validation and with survey writes that add or edit custom CSS; beyond it they return 429. Re-saving the same CSS and clearing it are never counted.

PATCH /api/v3/workspaces/{workspaceId}/custom-css

cURL

save

curl --request PATCH \
  --url https://app.formbricks.com/api/v3/workspaces/{workspaceId}/custom-css \
  --header 'Content-Type: application/json' \
  --cookie next-auth.session-token= \
  --data '
{
  "customCss": {
    "light": "[data-fb-part=\"button-primary\"] { border-radius: 999px; }",
    "dark": "#fbjs[data-appearance=\"dark\"] { --acme-ink: #e6eef5; }"
  }
}
'

200

{
  "data": {
    "workspaceId": "clxx1234567890123456789012",
    "customCss": {
      "light": "[data-fb-part=\"button-primary\"] { border-radius: 999px; }",
      "dark": null
    },
    "previous": null,
    "status": "ok",
    "canEdit": true,
    "planAllowed": true
  },
  "warnings": []
}

Authorizations

sessionAuthapiKeyAuthbearerAuth

next-auth.session-token · string · cookie · required

NextAuth session JWT cookie. Development: often next-auth.session-token. Production (HTTPS): often __Secure-next-auth.session-token. Send the cookie your browser receives after sign-in.

Path Parameters

workspaceId · string<cuid2> · required

Workspace identifier.

Body

application/json

customCss · object | null · required

Replaces both fields. null clears all workspace CSS. Adding or editing CSS needs the Scale plan on Formbricks Cloud; clearing either field or all CSS never does.

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Response

200

application/json

Workspace custom CSS saved (or unchanged)

data · object · required

A workspace's shared survey CSS (ENG-3641): editable source for authorized readers, never compiled output. It applies to every survey in the workspace, beneath each survey's own CSS.

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warnings · object[]

Processing warnings for this write: constructs the processor removed. Additive, returned beside data (never inside it, so data can be sent back unchanged); present only when the write processed custom CSS.

Maximum array length: 50

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