Adapters

#OpenTelemetry (OTLP)

@mmstack/telemetry-otel is the OTLP interchange adapter, built on the official OpenTelemetry JS SDK. One config exports traces, metrics, and logs to any OTLP-compatible backend: Datadog, Honeycomb, Grafana, a local collector, and so on.

import { provideTelemetry } from '@mmstack/telemetry-core';
import { otelSink } from '@mmstack/telemetry-otel';

provideTelemetry({
  sinks: [
    otelSink({
      endpoint: 'http://localhost:4318', // drives /v1/traces, /v1/metrics, /v1/logs
      headers: { 'x-api-key': '...' },
    }),
  ],
});

endpoint enables all three signals. Pass an existing WebTracerProvider to share one export pipeline with official OpenTelemetry instrumentation. Metrics run on a periodic reader, and the adapter flushes them when the page is hidden, so a short session still reports. All the OpenTelemetry packages are peer dependencies, so your app controls their versions and they dedupe.

#PostHog

@mmstack/telemetry-posthog is an event sink over your own posthog-js instance. No SDK is bundled. Events emitted inside a span carry the trace ids, so a PostHog event links back to the trace your OTLP backend received.

import posthog from 'posthog-js';
import { provideTelemetry } from '@mmstack/telemetry-core';
import { posthogSink } from '@mmstack/telemetry-posthog';

posthog.init('<key>', { api_host: 'https://eu.posthog.com' });

provideTelemetry({
  sinks: [posthogSink({ posthog })],
});

If the client exposes a session-replay URL, the adapter publishes it as a signal in the TelemetryHandles registry, keyed by sink name, so other code can attach the replay link to a span or an error.

#Sentry

@mmstack/telemetry-sentry is an error sink over your own Sentry SDK. Attributes ride as Sentry extra, and errors recorded inside a span carry the trace ids. The most recent event id is published as a signal, so you can deep-link to the captured event from a feedback dialog or a support id in the UI.

import * as Sentry from '@sentry/browser';
import { provideTelemetry } from '@mmstack/telemetry-core';
import { sentrySink } from '@mmstack/telemetry-sentry';

Sentry.init({ dsn: '<dsn>' });

provideTelemetry({
  sinks: [sentrySink({ sentry: Sentry })],
});

Send traces themselves to Sentry through the OTLP adapter. This adapter is for Sentry's error-tracking strength.

#Combining adapters

Provide several sinks at once. The facade fans each emit out to the sinks that support it and shares the trace ids across all of them, so a span, its errors in Sentry, and its analytics events in PostHog all correlate without any extra plumbing.

provideTelemetry({
  sinks: [
    otelSink({ endpoint: 'http://localhost:4318' }),
    sentrySink({ sentry: Sentry }),
    posthogSink({ posthog }),
  ],
});