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Use this when your application already sends traces to another backend (Datadog, Jaeger, Arize Phoenix, Langfuse, etc.) and you want to add Lemma without replacing your existing setup.

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Adding Lemma to a fresh provider

Build the TracerProvider manually and add both processors: 
import { NodeTracerProvider } from "@opentelemetry/sdk-trace-node";
import { BatchSpanProcessor } from "@opentelemetry/sdk-trace-base";
import { OTLPTraceExporter } from "@opentelemetry/exporter-trace-otlp-proto";
import { createLemmaSpanProcessor } from "@uselemma/tracing";

const provider = new NodeTracerProvider({
  spanProcessors: [
    createLemmaSpanProcessor(),
    new BatchSpanProcessor(
      new OTLPTraceExporter({ url: "https://your-collector/v1/traces" })
    ),
  ],
});

provider.register();
If you also use OpenInference, register its instrumentor against that same provider setup instead of replacing the provider afterward. Both processors receive all spans independently — processor order has no effect on correctness.

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Adding Lemma to an already-initialized provider

If a framework or APM agent already called trace.set_tracer_provider() before your code runs, add Lemma as an additional processor on the existing provider instead of replacing it: 
import { NodeTracerProvider } from "@opentelemetry/sdk-trace-node";
import { createLemmaSpanProcessor } from "@uselemma/tracing";

// Reuse the provider your app already created.
declare const provider: NodeTracerProvider;
provider.addSpanProcessor(createLemmaSpanProcessor());
Do not call registerOTel() / register_otel() if a provider is already registered. Use createLemmaSpanProcessor() / create_lemma_span_processor() and add it to the existing provider instead.

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Passing credentials explicitly

If environment variables are not available at startup: 
import { createLemmaSpanProcessor } from "@uselemma/tracing";

const processor = createLemmaSpanProcessor({
  apiKey: "lma_...",
  projectId: "proj_...",
  baseUrl: "https://api.uselemma.ai",
});