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Overview

Weave supports ingestion of OpenTelemetry compatible trace data through a dedicated endpoint. This endpoint allows you to send OTLP (OpenTelemetry Protocol) formatted trace data directly to your Weave project.

Endpoint details

Path: /otel/v1/traces Method: POST Content-Type: application/x-protobuf Base URL: The base URL for the OTEL trace endpoint depends on your W&B deployment type:
  • Multi-tenant Cloud:
    https://trace.wandb.ai/otel/v1/traces
  • Dedicated Cloud and Self-Managed instances:
    https://<your-subdomain>.wandb.io/traces/otel/v1/traces
Replace <your-subdomain> with your organization’s unique W&B domain, e.g., acme.wandb.io.

Authentication

Standard W&B authentication is used. You must have write permissions to the project where you’re sending trace data.

Required Headers

  • project_id: <your_entity>/<your_project_name>
  • Authorization=Basic <Base64 Encoding of api:$WANDB_API_KEY>

Examples:

You must modify the following fields before you can run the code samples below:
  1. WANDB_API_KEY: You can get this from https://wandb.ai/authorize.
  2. Entity: You can only log traces to the project under an entity that you have access to. You can find your entity name by visiting your W&N dashboard at [https://wandb.ai/home], and checking the Teams field in the left sidebar.
  3. Project Name: Choose a fun name!
  4. OPENAI_API_KEY: You can obtain this from the OpenAI dashboard.

OpenInference Instrumentation:

This example shows how to use the OpenAI instrumentation. There are many more available which you can find in the official repository: https://github.com/Arize-ai/openinference First, install the required dependencies:
Performance Recommendation: Always use BatchSpanProcessor instead of SimpleSpanProcessor when sending traces to Weave. SimpleSpanProcessor exports spans synchronously, potentially impacting the performance of other workloads. These examples illustrate BatchSpanProcessor, which is recommended in production because it batches spans asynchronously and efficiently.
Next, paste the following code into a python file such as openinference_example.py
Finally, once you have set the fields specified above to their correct values, run the code:

OpenLLMetry Instrumentation:

The following example shows how to use the OpenAI instrumentation. Additional examples are available at https://github.com/traceloop/openllmetry/tree/main/packages. First install the required dependencies:
Next, paste the following code into a python file such as openllmetry_example.py. Note that this is the same code as above, except the OpenAIInstrumentor is imported from opentelemetry.instrumentation.openai instead of openinference.instrumentation.openai
Finally, once you have set the fields specified above to their correct values, run the code:

Without Instrumentation

If you would prefer to use OTEL directly instead of an instrumentation package, you may do so. Span attributes will be parsed according to the OpenTelemetry semantic conventions described at https://opentelemetry.io/docs/specs/semconv/gen-ai/gen-ai-spans/. First, install the required dependencies:
Next, paste the following code into a python file such as opentelemetry_example.py
Finally, once you have set the fields specified above to their correct values, run the code:
The span attribute prefixes gen_ai and openinference are used to determine which convention to use, if any, when interpreting the trace. If neither key is detected, then all span attributes are visible in the trace view. The full span is available in the side panel when you select a trace.

Organize OTEL traces into threads

Add specific span attributes to organize your OpenTelemetry traces into Weave threads, then use Weave’s Thread UI to analyze related operations like multi-turn conversations or user sessions in Weave’s thread UI. Add the following attributes to your OTEL spans to enable thread grouping:
  • wandb.thread_id: Groups spans into a specific thread
  • wandb.is_turn: Marks a span as a conversation turn (appears as a row in the thread view)
The following code shows several examples of organizing OTEL traces into Weave threads. They use wandb.thread_id to group related operations, and use wandb.is_turn to view high level operations as rows in the thread view. Each example performs the followingmark high-level operations that appear as rows in the thread view).
Use this configuration to run these examples:
After sending these traces, you can view them in the Weave UI under the Threads tab, where they’ll be grouped by thread_id and each turn will appear as a separate row.

Attribute Mappings

Weave automatically maps OpenTelemetry span attributes from various instrumentation frameworks to its internal data model. When multiple attribute names map to the same field, Weave applies them in priority order, allowing frameworks to coexist in the same traces.

Supported Frameworks

Weave supports attribute conventions from the following observability frameworks and SDKs:
  • OpenTelemetry GenAI: Standard semantic conventions for generative AI (gen_ai.*)
  • OpenInference: Arize AI’s instrumentation library (input.value, output.value, llm.*, openinference.*)
  • Vercel AI SDK: Vercel’s AI SDK attributes (ai.prompt, ai.response, ai.model.*, ai.usage.*)
  • MLflow: MLflow tracking attributes (mlflow.spanInputs, mlflow.spanOutputs)
  • Traceloop: OpenLLMetry instrumentation (traceloop.entity.*, traceloop.span.kind)
  • Google Vertex AI: Vertex AI agent attributes (gcp.vertex.agent.*)
  • OpenLit: OpenLit observability attributes (gen_ai.content.completion)
  • Langfuse: Langfuse tracing attributes (langfuse.startTime, langfuse.endTime)

Attribute Reference

Limitations

  • The Weave UI does not support rendering OTEL trace tool calls the Chat view. They appear as raw JSON, instead.