@rawdash/connector-langfuse

Sync LLM traces, daily observation volume and cost by model, and feedback scores from a Langfuse project.

Install

npm install @rawdash/connector-langfuse

Authentication

A Langfuse public + secret API key pair scoped to one project is required. The connector authenticates over HTTP Basic auth (publicKey:secretKey).

1. Open Langfuse -> Settings -> API Keys and create a new key pair for the project you want to sync.
2. Copy both the public key (pk-lf-...) and the secret key (sk-lf-...). The secret is shown once.
3. Set host to your instance base URL - https://cloud.langfuse.com (or the US/EU regional variants) for Langfuse Cloud, or your self-hosted origin (no trailing slash).
4. Store the secret as a secret and reference it from config as secretKey: secret("LANGFUSE_SECRET_KEY"), alongside the plaintext publicKey.

Configuration

| Field | Type | Required | Description | | -------------- | ------ | -------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | publicKey | string | Yes | Langfuse public API key for the project (starts with pk-lf-). Created in Langfuse -> Settings -> API Keys. | | secretKey | secret | Yes | Langfuse secret API key for the project (starts with sk-lf-). Issued alongside the public key in Langfuse -> Settings -> API Keys. | | host | string | No | Langfuse instance base URL. Use https://cloud.langfuse.com (US) or https://us.cloud.langfuse.com / https://eu.cloud.langfuse.com for Langfuse Cloud, or your self-hosted origin. No trailing slash. | | lookbackDays | number | No | How many calendar days of history to backfill on a full sync. Defaults to 30. | | resources | array | No | Which Langfuse resources to sync. Omit to sync all of them. |

Resources

• langfuse_trace (entity) - LLM traces in the project, keyed by id, with name, owning user/session, optional release/version, aggregate cost in USD, aggregate latency in milliseconds, and the createdAt timestamp.
  • Endpoint: GET /api/public/traces
  • Traces upsert by id on every run. Trace input/output payloads are not stored.
  • name: Trace name set by the SDK.
  • projectId: Langfuse project id the trace belongs to.
  • userId: Attached userId, if any.
  • sessionId: Attached sessionId, if any.
  • release: Release identifier from the SDK, if set.
  • version: Version identifier from the SDK, if set.
  • totalCost: Aggregate trace cost in USD across all observations.
  • latencyMs: End-to-end trace latency in milliseconds.
  • createdAt: ISO timestamp of trace creation.
• langfuse_observations_per_day (metric) - Daily LLM observation volume, total tokens, and total cost rolled up by model from the Langfuse daily metrics endpoint. One sample per (day, model) over the lookback window.
  • Endpoint: GET /api/public/metrics/daily
  • Unit: observations
  • Granularity: Daily (UTC)
  • Dimensions: model, countObservations, inputTokens, outputTokens, totalTokens, costUsd
  • Rollup metrics are stamped at UTC midnight of the day they cover.
• langfuse_scores (metric) - Daily Langfuse score rollups by score name. One sample per (day, name): the mean numeric value across that day and the count of scores written.
  • Endpoint: GET /api/public/scores
  • Unit: scores
  • Granularity: Daily (UTC)
  • Dimensions: name, average, count
  • Only numeric scores contribute to the average; non-numeric scores still increment the count.

Example

import {
  defineConfig,
  defineDashboard,
  defineMetric,
  secret,
} from '@rawdash/core';

const langfuse = {
  name: 'langfuse',
  connectorId: 'langfuse',
  config: {
    publicKey: 'pk-lf-...',
    secretKey: secret('LANGFUSE_SECRET_KEY'),
    host: 'https://cloud.langfuse.com',
  },
};

export default defineConfig({
  connectors: [langfuse],
  dashboards: {
    llm: defineDashboard({
      widgets: {
        daily_observations: {
          kind: 'timeseries',
          title: 'LLM observations per day',
          window: '30d',
          metric: defineMetric({
            connector: langfuse,
            shape: 'metric',
            name: 'langfuse_observations_per_day',
            fn: 'sum',
          }),
        },
      },
    }),
  },
});

Rate limits

Langfuse Cloud applies per-project rate limits (around 1000 requests/min on paid plans); 429 responses with Retry-After are honored.

Limitations

• One key pair scopes the sync to a single Langfuse project; sync multiple projects by adding one connector instance per project.
• Trace bodies (input/output payloads) are not synced - only the trace envelope plus aggregated cost / token / latency.
• Session and dataset endpoints are out of scope for the initial release.

Links

• Rawdash docs
• Langfuse API docs
• GitHub

License

Apache-2.0