The best W&B Weave alternatives

8 tools that do a similar job to W&B Weave, 4 of them open source. Each entry says what it does and who it suits, so you can pick the one that fits instead of the most famous.

You're replacing

W&B Weave

Weights & Biases' toolkit for tracing, evaluating and comparing LLM application versions.

1. 1

   promptfoo

   Open source · MIT · ★ 26.7k

   CLI and library for testing LLM prompts and red-teaming AI apps, with declarative configs.

   Best for: Developers building apps on top of LLM APIs who want repeatable prompt tests; Teams comparing several models side by side on the same prompts

   Full review W&B Weave vs promptfoo
2. 2

   Braintrust

   AI tool · Freemium

   An evaluation and observability platform for scoring prompts and models against datasets and monitoring production.

   Best for: Systematic evals before shipping; Comparing prompt versions with scores

   Full review W&B Weave vs Braintrust
3. 3

   Helicone

   AI tool · Freemium

   An open-source LLM observability proxy that logs requests, costs and latency with a one-line integration.

   Best for: Quick cost and usage visibility; Caching and rate limiting LLM calls

   Full review W&B Weave vs Helicone
4. 4

   Langfuse

   AI tool · Open source

   An open-source LLM engineering platform for tracing, prompt management, evaluations and cost tracking.

   Best for: Tracing LLM apps in production; Self-hosted prompt management

   Full review W&B Weave vs Langfuse
5. 5

   Arize Phoenix

   AI tool · Open source

   An open-source tool for tracing, evaluating and experimenting with LLM and agent applications, built on OpenTelemetry.

   Best for: Local debugging of LLM traces; OpenTelemetry-based stacks

   Full review W&B Weave vs Arize Phoenix
6. 6

   LangSmith

   AI tool · Freemium

   LangChain's platform for tracing, evaluating and monitoring LLM apps, with a prompt hub and playground.

   Best for: LangChain and LangGraph users; Dataset-based evaluation

   Full review
7. 7

   Opik

   AI tool · Open source

   Comet's open-source platform for logging, evaluating and monitoring LLM apps, including prompt optimisation.

   Best for: Open-source tracing and evals; Automated prompt optimisation

   Full review
8. 8

   Confident AI (DeepEval)

   AI tool · Freemium

   The cloud platform behind DeepEval, an open-source framework for unit-testing LLM outputs with ready-made metrics.

   Best for: Pytest-style LLM tests; RAG evaluation metrics

   Full review

How we pick: tools in the same category that solve the same problem, projects that name each other as alternatives, and open-source projects that describe themselves as an alternative to W&B Weave. We don't take payment for placement.