Best Langfuse Alternatives in 2026

Helicone is an open-source LLM observability platform and AI gateway from YC W23. One URL swap gives teams cost tracking, request logging, semantic caching, and prompt management across OpenAI, Anthropic, and 100+ models. Used by 16,000 organizations before its March 2026 acquisition by Mintlify.

PostHog is the open-source, all-in-one analytics platform built for engineers. It replaces Mixpanel, Hotjar, LaunchDarkly, and more in a single stack, with a free tier generous enough that over 90% of teams pay nothing.

Weights & Biases is the standard ML experiment tracking platform used by over a million AI engineers. It covers model training workflows with W&B Models and LLM observability with W&B Weave, now under CoreWeave ownership since May 2025.

MLflow is the open-source AI engineering platform used by thousands of enterprises to track experiments, manage model registries, and deploy classical ML and GenAI applications. Free under Apache 2.0, with 30 million monthly downloads.

RAGFlow is InfiniFlow's open-source enterprise RAG engine, built around a neural document parser (DeepDoc) that handles complex PDFs, tables, and mixed-layout documents. Self-hostable, Apache 2.0, with 79k+ GitHub stars.

Weaviate is an open-source vector database that stores objects and embeddings together, enabling hybrid search, RAG pipelines, and AI agent workflows. Available self-hosted under BSD-3 license or as a managed service via Weaviate Cloud on AWS, GCP, and Azure.

Anyscale is a managed Ray cluster platform built by the UC Berkeley team that created Ray. It handles distributed ML training, batch inference, fine-tuning, and model serving across multi-cloud GPU clusters, with no infrastructure management required.

Braintrust is an eval-first observability platform for teams shipping LLM products, wiring tracing, datasets, scorers, and CI/CD quality gates into one workflow. Used by OpenAI, Stripe, and Notion, it is premium and proprietary, with a steep jump from free to paid.

Qdrant is an open-source vector search engine built in Rust by a Berlin-based team. It powers production RAG, semantic search, and recommendation systems for enterprises including Canva, HubSpot, and TripAdvisor, with Apache 2.0 licensing and flexible deployment from laptop to edge device.

Predibase is a managed fine-tuning and inference platform for open-source LLMs, built on LoRAX multi-adapter serving. It lets teams run hundreds of fine-tuned model variants on a single GPU, with VPC deployment for enterprises that can't move training data to shared infrastructure.