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API Reference

The CampaignLark REST API lets you programmatically manage contacts, tags, fields, segments, and events within your workspace. Use it to integrate CampaignLark with your application and/or sync data from external systems.

Base URL​

All API requests are made to:

https://api.campaignlark.com/v1

Authentication​

Every request must include your API key in the Authorization header using the Bearer scheme:

Authorization: Bearer <YOUR_API_KEY>

API keys are scoped to a single workspace and can be created from the CampaignLark dashboard. Keep your API key secret, do not expose it in client-side code or public repositories.

Authentication Errors​

Missing API Key - 401 Unauthorized

{
  "error": {
    "message": "Please provide a valid API key in the Authorization header."
  }
}

Invalid or Revoked API Key - 401 Unauthorized

{
  "error": {
    "message": "The API key you provided is invalid or has been revoked."
  }
}

IP Not Allowed - 403 Forbidden

{
  "error": {
    "message": "Your IP address is not authorized to use this API key."
  }
}

Rate Limiting​

API requests are limited to 100 requests per second per workspace. This limit ensures reliable performance and protects the platform from excessive or abusive traffic. If the limit is exceeded, requests may be temporarily throttled and return a 429 response.

The POST /v1/events endpoint is subject to both a monthly event usage quota and a per-second ingestion limit tied to your workspace's billing plan.

Maximum ingestion rate: 100 events per second per workspace

Monthly quota: Defined by your billing plan

If either limit is exceeded, the endpoint will return a 429 Too Many Requests error:

{
    "error": {
        "message": "You have exceeded your event usage limit."
    }
}