LangSmith vs Rhesis AI

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.

Rhesis AI is an open-source collaboration layer for developing and evaluating AI agents. Domain experts, engineers, and product managers can work in a shared space to review test cases and agent versions, annotate them, and record expectations. Teams can generate test sets from application requirements or constraints, including single-turn prompts and multi-turn conversations, then run them against an application endpoint and evaluate responses using configured metrics. Results are saved in test runs. Rhesis Tracing uses OpenTelemetry to capture language-model calls, tool invocations, and retrieval operations in test or production mode. Evaluation options include offline evaluation, online trace metrics, LLM-as-a-judge, custom metrics, and adversarial red-teaming. Model providers connect through LiteLLM, including cloud and local options such as OpenAI, Anthropic, Google Gemini, Mistral, Ollama, and vLLM. Teams can use DeepEval and Ragas metrics or import Garak probes. A REST API supports test sets, runs, results, and trace inspection for integrations and CI/CD. Rhesis offers managed, Docker-local, and self-hosted use; it says it is developed in Germany and hosted in the EU. Both listed free editions cost $0.