Apirelio vs Langfuse

Apirelio provides customer-aware observability for B2B APIs, linking errors, releases, and API versions to affected customers and integrations. Its explainable customer health score combines usage, reliability, latency, endpoint adoption, and regularity. Release comparisons use an equally long preceding baseline to identify endpoint regressions and affected customers. It can also compare a proposed OpenAPI contract with the current contract and connect risky changes to production traffic and customers. Integration journeys follow accounts from first connection through first success, production, adoption, and regular usage, helping surface stalled integrations. Alerts for inactivity, high error rates, or traffic drops can go to Slack, Teams, signed webhooks, or scheduled email recipients. The site lists framework integrations across PHP, JavaScript, Python, Ruby, Go, Java, and ASP.NET Core ecosystems. Apirelio says its SDKs do not capture request or response bodies, credentials, cookies, query strings, or client IP addresses as analytics dimensions. The Free plan lists 50K events per month, one project, 7-day retention, and one member. Growth costs $19 a month after a 14-day free period, with 2M events per month, five projects, 30-day retention, and five members.

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.