tuft-telemetry

An Expo-first flight recorder for coding agents. It owns Expo context, a durable journal, installation identity, lifecycle/network state, JavaScript error capture, route breadcrumbs, delivery, and cleanup.

Quick start

The endpoint is the collector's base machine URL. The SDK appends /v1/events. The bearer token authorizes exactly one stream; the app never selects or sends a stream ID.

import { createExpoTelemetry } from "tuft-telemetry/expo";

export const telemetry = createExpoTelemetry({
  endpoint: process.env.EXPO_PUBLIC_TUFT_TELEMETRY_URL!,
  token: process.env.EXPO_PUBLIC_TUFT_TELEMETRY_WRITE_TOKEN!,
});

Initialization persists an installation ID, emits app.launch with build/update/device context, installs lifecycle/network listeners, chains the React Native global error handler, and tracks unhandled rejections. shutdown() restores installed handlers/listeners.

Expo Router is an optional entry point so non-Router apps still bundle:

import { installExpoRouterTelemetry } from "tuft-telemetry/expo-router";

export const removeRouterTelemetry = installExpoRouterTelemetry(telemetry);

Instrument causal phases rather than every function call:

const span = telemetry.startSpan("message.open", { source: "inbox" });
try {
  span.event("cache.checked", { hit });
  const message = await loadMessage();
  span.end({ bodyBytes: message.bodyBytes });
} catch (error) {
  span.fail(error, { phase: "network" });
  throw error;
}

Lower-level constructors and adapters remain exported for tests and custom integrations. See the protocol, privacy model, and limitations.