Install the Node SDK

The spanslice package is an OpenTelemetry setup for Node. It fetches the rules your project defines in SpanSlice, applies them to every span in your process, and picks up changes without a restart.

Install

npm install spanslice

Get an API key

Each runtime environment (production, staging, …) has its own API key, under your project’s Settings › API keys in the app. Set it as SPANSLICE_API_KEY wherever that environment runs. Without a key the SDK stays off.

Initialise before your app loads

Create a file that starts the SDK and load it with --import, so instrumentations can patch libraries before your code imports them:

src/instrument.ts

import { spanSliceInit } from 'spanslice'
import { HttpInstrumentation } from '@opentelemetry/instrumentation-http'

const telemetry = spanSliceInit({
  service: 'api', // the service in SpanSlice; also service.name
  instrumentations: [new HttpInstrumentation()],
})
await telemetry.ready

node --import ./src/instrument.ts server.js

service must be a service deployed to the API key’s environment, otherwise the SDK stays off.

ready resolves once the first config has applied, or after readyTimeoutMs (5 seconds by default) if the API can’t be reached. Until the first config arrives, the SDK holds spans rather than sending them unfiltered.

Main options

Option / env	Default	Meaning
apiKey / SPANSLICE_API_KEY	—	The environment’s ss_… key.
service	OTEL_SERVICE_NAME	The service’s slug or name in SpanSlice.
exporter / SPANSLICE_EXPORTER	remote	remote (where the project sends data), otlp (your own collector), console, or none.
configFile / SPANSLICE_CONFIG_FILE	—	A config written by spanslice prefetch, applied at boot without waiting on the API.
readyTimeoutMs	5000	How long ready waits for the first config.
apiUrl / SPANSLICE_API_URL	https://api.spanslice.com	Where the SDK fetches its config.

With the default remote exporter, SpanSlice tells the SDK where to send data (for example, your Honeycomb environment), so your code names no vendor. Spans go straight from your process to that backend; they don’t pass through SpanSlice.

Next: write your first rule.