Langfuse vs ProofHound

Langfuse is an open-source AI engineering platform for teams debugging, analyzing, and iterating on AI agent applications. Its tracing records prompts, model responses, token use, latency, tool calls, retrieval steps, and metadata. Prompt Management stores, versions, deploys, and tests prompts, then links them to traces. Evaluation features include LLM-as-a-judge, code evaluators, user feedback, manual labeling, datasets, and experiments. Integrations include Python and JS/TS SDKs, OpenTelemetry, an API, CLI, MCP Server, and popular AI frameworks. Teams can self-host the MIT-licensed core on customer infrastructure using Docker, with options including Docker Compose, Kubernetes, AWS, and Azure. Langfuse reports annual SOC 2 Type 2 and ISO 27001 audits, external penetration tests, GDPR compliance, a DPA, and a HIPAA-ready region. Its Cloud traffic uses TLS 1.2+ and stored data uses AES-256 encryption. The free Hobby plan is free and includes 50k units per month, 30 days of data access, two users, and community support via GitHub. Core costs $29 a month, billed monthly.

ProofHound is a prompt-optimization platform for LLM classification work, available through an API, self-hosted deployment, or the web. It examines error cases, iterates prompts, validates outputs, and provides controlled deployment and rollback. Dataset uploads accept CSV, TSV, JSONL, JSON arrays, and ZIP files, with field mapping in the interface. Optimization can target overall accuracy or category measures such as recall for high-risk categories and precision for error-prone classes. Immutable prompt versions retain variable configurations, output rules, and differences between revisions. Experiment records include datasets, model configurations, sample judgments, and overall and category metrics. Release controls include gray traffic, A/B testing, full rollout, and one-click rollback. Connections include the web UI, webhooks, API tokens, and MCP. Customers supply their own model provider, and ProofHound says model calls are not charged. A free plan is listed at free, while self-hosted open source is also free.