What are the limits to the Langfuse API?
While the Langfuse API is extremely open and flexible, there are some limits to ensure the stability and performance of the platform.
Langfuse Cloud
If you run into unexpected limits or need to increase your limits, please reach out to us via the chat widget.
Payloads
5MB per request and 5MB per response
Request Constraints
- Trace Deletion: We advise strongly against trying to send more than 30-50 trace ids in a single DELETE request. Consider using data retention to automatically delete old traces instead of manual deletion.
Rate Limits
Langfuse Cloud groups API requests into per-organization resource buckets shared by all projects and API keys in the organization. Resources with dedicated buckets are listed separately from the General API bucket. Closely related buckets with identical limits may be combined in one row.
| Resource bucket | Applies to | Hobby | Core | Pro/Team/Enterprise |
|---|---|---|---|---|
| Tracing | Batched /ingestion and /otel endpoints used by SDKs and integrations to ingest traces. | 1,000 req/min | 4,000 req/min | 20,000 req/min |
| Deprecated tracing | Deprecated ingestion endpoints. | 100 req/min | 400 req/min | 400 req/min |
| Trace data deletion | Public API endpoints used to delete trace data, including traces, observations, and scores. | 50 req/day | 200 req/day | 1,000 req/day |
| Prompts | GET APIs used to fetch prompts for use in applications. | No limit | No limit | No limit |
| Metrics API v2 | GET /api/public/v2/metrics for aggregate analytics data. | 100 req/day | 100 req/hour | 500 req/hour |
| Deprecated Metrics API | Deprecated GET /api/public/metrics endpoint. | 100 req/day | 2,000 req/day | 2,000 req/day |
| Datasets | APIs used to work with datasets and experiments. | 100 req/min | 200 req/min | 1,000 req/min |
| Deprecated read APIs | Older trace, observation, and session read endpoints, listed below. | 15 req/min | 30 req/min | 100 req/min |
| General API | All other public APIs, including Observations API v2 (GET /api/public/v2/observations). | 30 req/min | 100 req/min | 1,000 req/min |
The deprecated read APIs are GET /api/public/traces, GET /api/public/traces/{traceId}, GET /api/public/observations, GET /api/public/observations/{observationId}, GET /api/public/sessions, and GET /api/public/sessions/{sessionId}.
MCP shares the General API resource bucket. Authenticated requests to the Langfuse MCP server at /api/public/mcp count toward the General API limit shown above.
On the Enterprise plan, you can request custom rate limits by contacting support.
Rate limit response
- HTTP status code 429
Retry-Afterresponse header with the number of seconds to wait before retrying
Self-hosted instances
No hard limits, depends on your infrastructure capacity and load-balancer configuration.
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