Helicone vs LangSmith

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.

LangSmith is a commercial agent-engineering platform for building, evaluating, deploying, monitoring, and improving AI agents. It supports offline evaluations on curated datasets and real-time scoring of production interactions. Evaluation methods include human review, heuristic checks, LLM-as-judge evaluators, pairwise comparisons, and custom Python or TypeScript evaluators. Annotation queues route runs to subject-matter experts for feedback that can calibrate evaluations, improve prompts, or augment datasets. The Playground compares prompt versions or model providers, and LangSmith chat can auto-improve prompts. Observability includes agent and retrieval tracing, token and general cost tracking, trajectory monitoring, online evaluations, and webhook or PagerDuty alerts. Traces can arrive through SDKs or an API from LangGraph, custom Python, or other stacks; SDKs are listed for Python, TypeScript, Go, and Java. Hosting ranges from cloud to hybrid and self-hosted Enterprise options. The Developer plan costs nothing, Plus costs $39 a month, and Enterprise pricing is custom.