Langfuse is an open-source observability and prompt-management platform. Traces are read-only — there's no re-execution, policy enforcement, or signed compliance artifact.
| Capability | Langfuse | Runback | Note |
|---|---|---|---|
| Read and search traces | ✓ | ✓ | |
| Prompt versioning and management | ✓ | ✓ | Versioned registry with movable labels (production/staging), a runtime-fetch endpoint, and a playground |
| Self-hostable | ✓ | ✓ | Both self-hostable. Langfuse is open source (MIT); Runback is source-available — the replay and audit core is not open source. Langfuse v3 needs Postgres + ClickHouse + Redis + S3-compatible storage, not Postgres alone |
| Re-execute any step from captured inputs | ✗ | ✓ | Runback's core capability — bisect a divergence in log₂ tries |
| Live policy enforcement — block before it runs | ✗ | ✓ | Langfuse's own docs call it an ex-post assessment tool that scores external guardrail verdicts, not a live blocker |
| CI release gate | ✓ | ✓ | Shipped May 2026 (langfuse/experiment-action) — fails the PR on score regressions; evaluates a dataset, not a specific captured production run against real history the way Runback's gate does |
| Signed, tamper-evident audit export | ✗ | ✓ | Traces are stored for search and analysis; the public documentation describes no hash chain or signature over them, so we see no basis for verifying a trace independently of Langfuse |
| Regulatory mappings (EU AI Act · CPS 230 · NIST) | ✗ | ✓ | |
| Independent roadmap | partial | ✓ | Acquired by ClickHouse, Jan 2026 — ClickHouse states the license, self-hosting, and roadmap are unchanged, but it's no longer a standalone company |
| Redact PII/secrets before data leaves your process | partial | ✓ | Langfuse's mask()/mask_otel_spans() is real, but it's a batch-level hook with no guarantee it sees a complete trace and can't touch span structure — Runback's SDK redacts each event in-process as it's captured |
| No metered overage billing | ✗ | ✓ | Langfuse bills consumption-based overage per unit (trace/observation/score) beyond the plan's included volume — Runback caps usage per tier and prompts an upgrade instead of a variable bill |
| Purpose-built Go SDK | ✗ | ✓ | Langfuse has no first-party Go SDK — Go apps go through a generic OpenTelemetry exporter only, with no Langfuse-specific ergonomics or redaction. Runback's Go SDK has the same manual-recording shape (and redaction) as its TS/Python SDKs |
Traces are read-only — there's no re-execution, policy enforcement, or signed compliance artifact. Most teams use both — Langfuse for what it's already good at, Runback for the incident replay, CI gate, and signed record it doesn't do.
Compiled from Langfuse's public documentation at https://langfuse.com/docs, read on 15 September 2026. Products change; if a row is out of date or wrong, tell us at legal@runback.dev and we will correct it. All product names and trade marks are the property of their respective owners. Runback is not affiliated with, endorsed by, or sponsored by any of them.
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