Arize Phoenix vs Helicone

Arize Phoenix is free, open-source software for tracing, evaluating, debugging, and improving AI applications. It captures model calls, retrieval, tool use, and custom logic as OpenTelemetry traces. Teams can score traces and spans with LLM evaluators, code checks, or human labels. Prompt tools provide versioning, side-by-side testing, and call replay, while dataset experiments compare evaluation results across application versions. Documented integrations include LlamaIndex, LangChain, DSPy, OpenAI, Bedrock, and Anthropic, plus evaluation libraries such as Harbor, Ragas, Cleanlab, and MLflow. Phoenix runs locally or can be self-hosted with Docker, Kubernetes, or a cloud environment; Arize says self-hosting keeps traces in the user’s environment. Self-hosted authentication supports OAuth2 identity providers with an OpenID Connect well-known endpoint. The Phoenix plan costs nothing and leaves trace spans, ingestion, projects, and retention under user management. The project is ELv2 licensed and built by Arize AI and the open-source community.

Helicone routes, debugs, and analyzes AI applications through a gateway and observability tools. The gateway provides access to more than 100 models through the OpenAI SDK by changing the model name, and supports load balancing, automatic failovers, and response caching across providers. Helicone logs requests in real time and visualizes multi-step LLM interactions to help locate error causes. Listed integrations include OpenAI, Anthropic, Azure, LiteLLM, Anyscale, Together AI, and OpenRouter. It can run in customer infrastructure through single-click deployment or a production-ready Helm chart; Helicone also states that its cloud is SOC 2, HIPAA, and GDPR compliant. A LangGraph integration tracks calls, sessions, performance, and costs, while an API cost calculator covers more than 300 models and providers. The free Hobby plan includes 10,000 requests, 1 GB storage, one seat, one organization, and seven days of retention. Pro costs $79.00 per month. A seven-day trial is advertised. Helicone says its services remain live in maintenance mode following acquisition by Mintlify, with security updates, new models, and bug and performance fixes continuing.