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Langfuse vs WunderGraph Cosmo
Short answer: Pick Langfuse if you want LLM observability & analytics; pick WunderGraph Cosmo if you want open-source GraphQL federation platform. Langfuse has a free plan, paid from $29/month; WunderGraph Cosmo has a free plan, paid from $499/month.
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LangfuseOpen Source Observability & Analytics for LLM Apps 🕵️♂️
WunderGraph Cosmo A drop-in replacement for Apollo GraphOSWhich to pick
Pick Langfuse if you want…
- LLM observability & analytics
- The lower starting price: $29/month against $499/month
- Integrations with Python, TypeScript or Java (on Langfuse's list, not WunderGraph Cosmo's)
Pick WunderGraph Cosmo if you want…
- Open-source GraphQL federation platform
- Integrations with Kafka, NATS or Redis (on WunderGraph Cosmo's list, not Langfuse's)
Side by side
- What it is
- Langfuse:Langfuse is an open-source platform for tracing, evaluating and monitoring LLM applications and AI agents.
- WunderGraph Cosmo:WunderGraph Cosmo is an open-source GraphQL federation platform for building, managing and scaling federated APIs.
- Best for
- Langfuse:LLM observability & analytics
- WunderGraph Cosmo:Open-source GraphQL federation platform
- Who it’s for
- Langfuse:Developers building, debugging and scaling LLM-based apps and agents.
- WunderGraph Cosmo:Platform and engineering teams needing self-hosted or managed GraphQL federation.
- Pricing
- Langfuse:Freemium
- WunderGraph Cosmo:Freemium
- Starting price
- Langfuse:$29/month (Core)
- WunderGraph Cosmo:$499/month (Launch)
- Free plan or trial
- Langfuse:Free plan (Hobby)
- WunderGraph Cosmo:—
- Plans
- Langfuse:Hobby Free · Core $29 per month · Pro $199 per month · Enterprise $2499 per month
- WunderGraph Cosmo:Launch $499 per month · Scale $3499 per month
- Open source
- Langfuse:Yes, 35,097 GitHub stars
- WunderGraph Cosmo:Yes
- Works with
- Langfuse:Python, TypeScript, Go, Java, .NET, Ruby, PHP, Swift
- WunderGraph Cosmo:Go, Kafka, NATS, Redis, Prometheus, OpenTelemetry, Datadog
Langfuse features
- Hierarchical Traces. Capture every LLM call, tool invocation and retrieval step with filters for user, session, cost and latency.
- Prompt Management. Version, fetch, release and cache prompts separately from code with one-click deployments.
- Evaluation Engine. Run LLM-as-judge, heuristic or human-review evaluations on production data or experiments.
- Experiments & Datasets. Define test cases, run experiments and create golden datasets for continuous improvement.
- Dashboards & Alerts. Monitor cost, latency and quality via custom dashboards and automated alerts.
- Human Annotation. Collaborative human-in-the-loop workflows with annotation queues.
- Extensive Integrations. Supports Python, TypeScript, Go, Java, .NET, Ruby, PHP, Swift and 100+ agent frameworks and model providers.
- Self-hosted & Cloud Options. Available as hosted SaaS or self-hosted under MIT license.
WunderGraph Cosmo features
- Self-hosted Router. Run the Cosmo router on any infrastructure with full control.
- Event-Driven Federated Subscriptions. Combine GraphQL federation with Kafka, NATS or Redis for scalable subscriptions.
- OpenTelemetry & Prometheus Support. Integrates with existing observability stacks for metrics and tracing.
- Custom Router Modules. Extend the router with Go modules or gRPC plugins.
- Schema Registry & Studio. Manage schemas, query plans and analytics via a unified UI.
- Enterprise-grade Security. SOC 2 compliance, OIDC, SCIM and role-based access control on Cosmo Cloud.
Langfuse vs WunderGraph Cosmo FAQ
What is the difference between Langfuse and WunderGraph Cosmo?+
Langfuse provides LLM observability, unrelated to GraphQL federation.
Should I use Langfuse or WunderGraph Cosmo?+
Pick Langfuse if you want LLM observability & analytics, the lower starting price: $29/month against $499/month or integrations with Python, TypeScript or Java (on Langfuse's list, not WunderGraph Cosmo's). Pick WunderGraph Cosmo if you want open-source GraphQL federation platform or integrations with Kafka, NATS or Redis (on WunderGraph Cosmo's list, not Langfuse's).
Is Langfuse or WunderGraph Cosmo free?+
Langfuse has a free plan (Hobby); paid plans start at $29/month (Core). WunderGraph Cosmo has a free plan; paid plans start at $499/month (Launch).
Which is cheaper, Langfuse or WunderGraph Cosmo?+
Langfuse is cheaper to start with: Langfuse's Core plan ($29/month) against WunderGraph Cosmo's Launch plan ($499/month).
Is Langfuse or WunderGraph Cosmo open source?+
Yes, both are open source: Langfuse (langfuse/langfuse on GitHub) and WunderGraph Cosmo.
Do Langfuse and WunderGraph Cosmo integrate with the same tools?+
Partly. Both list Go. Langfuse also lists Python, TypeScript, Java, .NET and 9 more; WunderGraph Cosmo also lists Kafka, NATS, Redis, Prometheus and 2 more.
On DevHunt
Based on each tool's website and DevHunt data. Details may change; check the official sites.