LaunchDarkly vs Langfuse
Enterprise feature management, experimentation, release automation
vs. Open-source LLM engineering platform — observability, prompts, evals
Pricing tiers
LaunchDarkly
Developer (Free)
Free forever. Unlimited seats + flags + projects. 30 SDKs. 5K session replays/mo. 10M logs/traces.
Free
Foundation
$12/month per service connection + $10/month per 1K client-side MAU. Unlimited seats, experimentation, SSO.
$12/mo
Enterprise
Custom. Advanced targeting, release automation, workflows, approvals, SAML/SCIM, custom roles.
Custom
Guardian
Custom. All Enterprise + release monitoring, guardrail metrics, auto pause/rollback.
Custom
Langfuse
Hobby (Cloud Free)
Free. 50k units/month included. 30 days data access. 2 users. Community support.
Free
Self-Hosted (OSS)
MIT-licensed. Docker Compose or Kubernetes deployment. Unlimited.
$0 base (usage-based)
Core
$29/month. 100k units included ($8 per 100k overage). 90 days retention. Unlimited users. In-app support.
$29/mo
Pro
$199/month. 100k units included + same overage. 3 YEARS retention. Unlimited annotation queues. High rate limits.
$199/mo
Teams Add-on
+$300/month. Adds Enterprise SSO + fine-grained RBAC + dedicated Slack support to Pro.
$300/mo
Enterprise
$2,499/month. Everything + custom rate limits, uptime SLA, dedicated support engineer. Yearly options.
$2499/mo
Free-tier quotas head-to-head
Comparing developer on LaunchDarkly vs hobby on Langfuse.
| Metric | LaunchDarkly | Langfuse |
|---|---|---|
| No overlapping quota metrics for these tiers. | ||
Features
LaunchDarkly · 15 features
- AI Configs — Manage AI prompts, models, and parameters as flags.
- Approvals — Require co-sign before flag changes in prod.
- Audit Log — Every change logged with user + timestamp.
- Auto Pause/Rollback — Guardrail metrics auto-revert a bad release.
- Code References — Scan code for flag references + stale flag cleanup.
- Contexts — Multi-context targeting: user + organization + device in one evaluation.
- Experimentation — A/B/n testing with stat significance. Bayesian + frequentist.
- Feature Flags — Boolean, multivariate (string/number/JSON) flags with targeting rules.
- Observability — Logs + traces + errors linked to flag changes.
- Relay Proxy — Self-hosted evaluation proxy for compliance / low-latency.
- Release Pipelines — Progressive rollout workflows with guards + approvals.
- SAML / SCIM — Enterprise SSO + SCIM provisioning.
- Session Replay — Frontend session recordings tied to flag exposure.
- Targeting Rules — Rule-based targeting on user attributes, country, device, custom contexts.
- Workflows — Scheduled flag changes + conditional workflows.
Langfuse · 16 features
- Annotation Queues — Human reviewers rate traces. Unlimited on Pro+.
- Dashboards — Aggregate metrics, cost, quality across projects.
- Datasets — Curate test sets from production traces. Run experiments.
- EU Cloud Region — GDPR-compliant hosting in EU.
- Evaluations — LLM-as-judge, manual scores, custom model-graded evaluators.
- LLM Cost Tracking — Automatic cost calculation per provider/model.
- OpenTelemetry Native — OTel SDK → Langfuse endpoint works out of box.
- Playground — Test prompts + models + variables live.
- Prompt Management — Version, tag, label prompts. Reference from code by label.
- Public API — Full REST API for ingest, query, prompt management.
- Python @observe decorator — One-line decorator to trace any function.
- Self-Hosting — Docker Compose + k8s Helm chart.
- Sessions — Group related traces (conversations, agent runs).
- Tracing — Capture every LLM call, tool call, nested span with inputs/outputs/cost.
- Users Tracking — Segment traces by user ID, track per-user cost.
- Webhooks — Subscribe to trace completion events.
Developer interfaces
| Kind | LaunchDarkly | Langfuse |
|---|---|---|
| CLI | LaunchDarkly Relay Proxy | — |
| SDK | go-server-sdk, launchdarkly-android-client-sdk, launchdarkly-ios-client-sdk, launchdarkly-java-server-sdk, launchdarkly-js-client-sdk, launchdarkly-node-server-sdk, launchdarkly-react-client-sdk, launchdarkly-react-native-client-sdk, LaunchDarkly.ServerSdk, launchdarkly-server-sdk-python | langfuse-js, langfuse-python |
| REST | LaunchDarkly REST API | Langfuse REST API |
| MCP | — | Langfuse MCP Server |
| OTHER | Streaming Flag Eval, Webhooks | Langfuse Dashboard, OpenTelemetry endpoint |
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