
Open-source LLM observability & prompt management for production AI.
By Tanmay Verma, Founder · Last verified 26 Jun 2026
In short
Langfuse — Open-source LLM observability & prompt management for production AI. Best for Engineering teams building production LLM agents needing observability and debugging, Enterprises requiring self-hosted, SOC 2/HIPAA-compliant AI monitoring, Developers who want unified prompt management, evals, and experiments in one platform. Free to start; paid plans from $29/mo.
See what real users actually say. We scan live discussions, reviews and complaints across the web and hand you an honest verdict — in under a minute.
3 free scans · no card needed · downloadable report
Langfuse is the go-to open-source LLM observability platform if you need self-hosting, data portability, and a complete toolchain. Skip if you prefer a zero-config SaaS or are locked into a vendor ecosystem like LangSmith. Its recent additions—monitors/alerts, full-text search, code evaluators, and an MCP server—make it particularly strong for engineering teams running production agents. Self-hosting does require ops discipline; the Cloud tiers jump sharply above Pro.
Skip Langfuse if Skip Langfuse if you want a zero-config SaaS or are already locked into a vendor ecosystem like LangSmith.
Compare with: Langfuse vs Arize Phoenix, Langfuse vs Phoenix, Langfuse vs Lilypad
Last verified: June 2026
Across the latest 5 updates: 5 feature updates.
Create dataset items with images, audio, video, documents for SDK-based multi-modal experiments.
Create monitors for cost, quality, latency; notify via Slack, webhooks, GitHub Actions.
Ask natural-language questions about traces, observations, and metrics on Langfuse Cloud.
Fast query bar with operators, full-text search, wildcards, and autocomplete for filtering traces.
ClickHouse full-text search on Cloud, improving UI search and adding matches operator to Observations API.
How likely is Langfuse to still be operational in 12 months? Based on 4 signals — momentum (how recently it shipped), wrapper dependency, revenue model, and web presence.
Last calculated: June 2026
How we score →Langfuse is an open-source AI engineering platform that provides observability, prompt management, evaluation, and experimentation for LLM applications and agents. Built for developers and AI engineers, it helps debug, monitor, and improve LLM systems from prototype to production. Key features include hierarchical traces with cost/latency filtering, LLM-as-a-judge evaluations, one-click prompt deployment and rollback, playground for side-by-side model comparison, and human annotation workflows. Langfuse integrates with 100+ frameworks (LangChain, Vercel AI SDK, LiteLLM, etc.) and supports any OTel-instrumented stack. It scales to billions of events using ClickHouse and is self-hostable under MIT license. Unlike closed alternatives like LangSmith, Langfuse offers full data portability and a large open-source community with 29.8k GitHub stars. Recent additions include full-text search, code evaluators, monitors and alerts, and an MCP server for AI agent integration, making it a comprehensive solution for teams needing control and scale. As of June 2026, Langfuse Cloud now offers a Langfuse Assistant (public beta) for natural-language queries and multi-modal datasets.
Langfuse has become the de facto open-source standard for LLM observability. Its biggest strength is the breadth of its integrated toolchain: traces, prompts, evals, experiments, human annotation, and cost/latency dashboards all in one platform. The 100+ integrations and native OTel support mean you can plug it into almost any stack. Recent changelog additions—monitors and alerts (June 2026), full-text search, code evaluators, and the Langfuse Assistant for natural-language queries—show a team shipping fast. The MCP server and CLI for coding agents (Claude Code, Cursor) are smart bets for developer adoption. Weaknesses: self-hosting requires real ops discipline (ClickHouse isn't a set-it-and-forget database). Evals are good but less deep than dedicated eval platforms like Braintrust. Cloud pricing jumps sharply above Pro ($199/mo to $2499/mo), and high-volume workloads may need to sample traces to keep costs manageable. All in all, Langfuse is best for engineering teams building production LLM agents who want an open-core platform with control and scale.
Free, no signup — tell us your goal and get tools matched to your budget & existing stack.
Concrete scenarios for the personas Langfuse actually fits — and what changes day-one when you adopt it.
You deploy a new prompt version and want to monitor quality before rolling it out to all users. You set up an LLM-as-judge evaluator on production traces, create a monitor that alerts via Slack if the average score drops below 0.8, and run an experiment on historical data to validate the change.
Outcome: You catch a quality regression within minutes, roll back the prompt with one click, and re-deploy after fixing the issue—all without downtime or manual review.
Your team needs to provide self-hosted AI observability for 50 internal teams. You deploy Langfuse via Kubernetes Helm chart, configure SCIM API for user provisioning, set up audit logs, and create annotation queues for each team to label trace data for fine-tuning.
Outcome: Each team gets independent projects with RBAC, you have central cost and latency dashboards, and the enterprise meets SOC 2 and HIPAA compliance requirements.
You install the Langfuse MCP server and CLI. During development, you use natural language via the MCP to create traces and experiments. When testing a multi-modal feature with images, you use the new multi-modal datasets to build a test set and run side-by-side model comparisons.
Outcome: You debug complex agent loops quickly, compare costs across models, and ship with confidence—no code changes needed to enable observability.
Project the real annual outlay, including the implied monthly cost when only an annual tier is published.
Vendor list price only. Add-on usage, seat overages, and contract minimums are surfaced under Hidden costs & gotchas.
For each published Langfuse tier: who it actually fits, and what it adds vs. the previous tier. Cross-reference the cost calculator above for projected annual outlay.
Hobby
$0/mo
Ideal for
Individual developers or hobby projects exploring Langfuse with low volume (up to 50k units/mo) and minimal data retention needs.
What this tier adds
Free entry point with 50k units/month, 30-day data retention, 2 users, and community support only.
Core
$29/mo
Ideal for
Production projects that need longer data retention (90 days) and unlimited users at a low monthly cost.
What this tier adds
Adds 100k units/month, 90-day retention, unlimited users, in-app support, and 3 annotation queues vs Hobby's limits.
Pro
$199/mo
Ideal for
Scaling teams that require long-term data retention (3 years), high rate limits, and compliance reports (SOC2, ISO27001, HIPAA BAA).
What this tier adds
Adds 3-year data retention, data retention management, unlimited annotation queues, high rate limits, and compliance reports compared to Core.
Enterprise
$2499/mo
Ideal for
Large organizations needing SSO enforcement, audit logs, SCIM API, uptime SLA, and dedicated support.
What this tier adds
Adds audit logs, SCIM API, custom rate limits, uptime SLA, support SLA, dedicated support engineer, and yearly commitment discount over Pro.
The company stage and team size where Langfuse's pricing actually pencils out — and where peers do it cheaper.
Langfuse's Cloud pricing starts free at Hobby (50k units/mo). For production, Core at $29/mo (100k units, 90-day retention) beats Datadog or New Relic for LLM-specific observability. Pro at $199/mo adds long retention and compliance reports, but teams needing SSO must pay an extra $300/mo for Teams Add-on or jump to Enterprise at $2499/mo. Open-source competitors like Opik or Phoenix are cheaper if you self-host, but Langfuse offers more integrated features.
How long it actually takes to get something useful out of Langfuse — broken out by persona, not the marketing-page minute.
For developers familiar with SDKs, you can start sending traces in under 10 minutes by adding a few lines of code (Python or TypeScript). Setting up LLM-as-a-judge evals and monitors takes a few hours of configuration. Self-hosting via Docker Compose takes about 30 minutes; Kubernetes or Terraform for large-scale deployments may take half a day or more.
How to bring data in from common predecessors and how to get it back out — written for the switcher, not the buyer.
Langfuse is an open-source LLM engineering platform (GitHub) that helps teams collaboratively debug, analyze, and iterate on their LLM applications. All platform features are natively integrated to accelerate the development workflow.
End-to-end examples and resources to get started with Langfuse for LLM Tracing, Monitoring, Prompt Management, and more.
Understand why LLM engineering is different and how to navigate the full AI engineering lifecycle.
Traces, evals, prompt management and metrics to debug and improve your LLM application.
Traces, evals, prompt management and metrics to debug and improve your LLM application.
Overview of available support options for Langfuse.
Helpful link from langfuse.com
Common stack mates teams adopt alongside Langfuse, with the specific reason each pairing earns its keep.
Langfuse vs Promptfoo
Choose Promptfoo if your priority is AI security — automated red teaming, guardrails, and CI/CD scanning against 50+ attack types, backed by recent OpenClaw injection analysis and ModelAudit launch. Choose Langfuse if you need production LLM observability, prompt management, and evaluations with deep framework integration (100+), now with multi-modal datasets and monitors/alerts. Both are open-source, but Promptfoo leans security-first while Langfuse is engineering-first.
Langfuse vs Langgraph
Choose Langfuse if your priority is observability, debugging, and prompt management for production LLM apps, with a need for multi-modal evals and alerts. Choose LangGraph if you're building complex, stateful multi-agent systems that require fine-grained workflow control, human oversight, and deep integration with LangSmith for evaluation. They can complement each other—use LangGraph for orchestration and Langfuse for observability.
Langfuse vs Litellm
If you need a lightweight proxy to unify 100+ LLMs with cost attribution and fallbacks, LiteLLM is your gateway; if you need deep observability, prompt versioning, and evals, Langfuse is your observability hub. Both are open-source and integrate well, but LiteLLM excels at routing and spend control while Langfuse dominates debugging and experimentation. For a combined stack, use both: LiteLLM routes traffic, Langfuse traces it.
Langfuse vs Mlflow
If you need a single open-source platform that covers both traditional ML (experiment tracking, model registry) and LLM agents (tracing, prompt versioning, AI Gateway), choose MLflow. If your primary focus is production LLM observability with rich prompt management, evaluation workflows, and a mature SaaS option, Langfuse is more specialized and easier to adopt for LLM-only teams.
Langchain vs Langfuse
If you're building production multi-step agents and need advanced fault tolerance, human-in-the-loop, and distributed runtime, LangChain/LangSmith is the better choice—especially with its new Fleet agents and LangGraph fault tolerance. If you prioritize open-source, self-hosting, cost control, and unified observability/evals/prompt management across any framework, Langfuse wins with its MIT-licensed platform, multi-modal datasets, and flexible alerting. Choose LangChain for deep agent engineering; choose Langfuse for open, lightweight LLM operations.
Used Langfuse? Help shape our editorial sentiment research.