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OpenRouter logo
OpenRouter
✓ verifiedFreemium

Unified API gateway that routes requests to 400+ LLMs across 70+ providers with failover and no subscription.

17M visits/mo
Weights & Biases logo
Weights & Biases
✓ verifiedFreemium

Weights & Biases is a widely used MLOps platform for experiment tracking, model management and evaluating AI applications.

2.5M visits/mo
Arize AI logo
Arize AI
✓ verifiedFreemium

AI observability and evaluation platform to trace, evaluate and improve LLM agents in production, with an open-source Phoenix core.

248K visits/mo
liteLLM logo
liteLLM
✓ verifiedFreemium

Open-source AI gateway giving dev teams unified access, fallbacks and spend tracking across 100+ LLMs.

703K visits/mo
metaflow.org logo
metaflow.org
✓ verifiedFree

Open-source Python framework, born at Netflix, for building, scaling, and deploying real-world ML, AI, and data science workflows.

20K visits/mo
Pricing
Free: $0
Pay-as-you-go: Per-token, no subscription
Enterprise: Talk to sales

No public pricing

AX Free: $0/mo (25k spans/mo)
AX Pro: $50/mo (50k spans/mo)
Open Source: $0 (self-hosted, 100+ providers)

Free trial available

No public pricing

Core features
  • One unified, OpenAI-compatible API for 400+ models
  • Automatic provider failover for higher uptime
  • Edge routing for low latency
  • Custom data and provider policies
  • Pay-as-you-go credits usable across any model
  • Experiment tracking and visualization for ML training runs
  • Model and artifact versioning and management
  • Hyperparameter optimization tooling
  • Collaborative dashboards and reports for ML teams
  • LLM application tracing and evaluation tooling
  • Agent and LLM tracing
  • Large-scale evaluations
  • Open-source Phoenix observability
  • Alyx AI engineering agent
  • OpenTelemetry-based instrumentation
  • Experiments and prompt playgrounds
  • Unified access to 100+ LLMs in OpenAI format
  • Cost/spend tracking per key, user and team
  • Budgets and rate limiting
  • Automatic provider fallbacks and retries
  • Virtual keys and team management
  • Logging and observability integrations
  • Plain-Python workflow orchestration
  • Automatic versioning and experiment tracking
  • Scale-out compute with GPUs and parallel instances
  • One-command deployment to production
  • Runs on AWS, Azure, GCP, or Kubernetes
  • Event-based triggering of workflows
Use cases
  • Accessing many LLMs through one integration
  • Adding provider redundancy to AI apps
  • Comparing model price and performance
  • Powering agents and AI-native products
  • ML engineers tracking and comparing training experiments
  • Research teams versioning datasets and model checkpoints
  • Teams building and evaluating LLM-powered applications
  • Organizations collaborating on machine learning projects
  • Debugging AI agents in production
  • Measuring LLM output quality
  • Catching regressions before deploy
  • Giving developers governed access to many LLMs
  • Attributing and controlling LLM spend
  • Keeping apps running during provider outages
  • Developing and debugging ML pipelines locally
  • Scaling model training to cloud GPUs
  • Deploying experiments to production unchanged
  • Building reactive, event-driven data systems
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