langfuse/langfuse-js

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🪢 Langfuse JS/TS SDKs - Instrument your LLM app and get detailed tracing/observability. Works with any LLM or framework

Stars: 162
Forks: 108
Open beginner issues: 0
Indexed issues: 11
Avg merge: 11h 46m
Merged PRs (30d): 20

Dominant language: TypeScript
License: No license data
Last GitHub push: Sep 17, 2026
Latest indexed: Sep 18, 2026
Contributing guide: Contributing guide
Code of conduct: No code of conduct
Beginner labels: No beginner labels indexed

Beginner friendly Everything

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11 open issues indexed

langchain: ToolMessage serialized without role and tool_call_id — breaks "Open in Playground" for tool traces Open

bug feat-playground integration-langchain sdk-js

langfuse/langfuse-js#930 · 1 assignee · Opened Sep 1, 2026
LangfuseMedia({ source: "bytes" }) creates large transient Base64 allocations Open

bug feat-multimodal feat-otel integration-otel Migrated

langfuse/langfuse-js#901 · 1 assignee · Opened Aug 5, 2026
Update Vercel AI SDK integration to @ai-sdk/otel@1.0.44 Open

bug feat-otel integration-otel integration-vercel-ai-sdk Migrated sdk-js

langfuse/langfuse-js#898 · 1 assignee · Opened Jul 31, 2026
LANGFUSE_TIMEOUT is not applied to ScoreManager ingestion requests Open

Difficulty 3/5 1-2 days Newbie friendliness 74/100

langfuse/langfuse-js#883 · Opened Jul 23, 2026
@langfuse/tracing spans are non-recording in Next.js 16 App Router route handlers (route-layer @opentelemetry/api has no provider) Open

bug feat-otel feat-tracing integration-otel

langfuse/langfuse-js#878 · 1 assignee · Opened Jul 17, 2026
handleAgentAction registers its span under the chain's runId, splitting every AgentExecutor trace in two Open

bug integration-langchain sdk-js

langfuse/langfuse-js#867 · 1 comment · 1 assignee · Opened Jul 10, 2026
anySignal() leaks an abort listener on the caller's AbortSignal for every request (never removed on success) Open

bug sdk-js

langfuse/langfuse-js#858 · 1 assignee · Opened Jul 5, 2026
@langfuse/langchain CallbackHandler doesn't forward provider-reported cost (e.g. OpenRouter usage.cost) to costDetails Open

billing bug integration-langchain sdk-js

langfuse/langfuse-js#828 · 2 comments · 1 assignee · Opened Jun 12, 2026
CJS type mismatch when using `@langfuse/langchain` with TypeScript `nodenext` module resolution Open

langfuse/langfuse-js#748 · 1 comment · 1 assignee · Opened Mar 13, 2026
CallbackHandler not sending traces in LangGraph Open

langfuse/langfuse-js#686 · 5 comments · 2 reactions · 1 assignee · Opened Nov 2, 2025
All Langfuse Issues are in langfuse/langfuse Open

Difficulty 1/5 Under an hour Newbie friendliness 10/100

langfuse/langfuse-js#30 · Opened Sep 15, 2023

langfuse/langfuse-js

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