LangSmith is an excellent trace viewer and dataset manager for LangChain apps. It shows what happened. It can't re-execute the step, gate your CI pipeline, or produce a signed audit record.
| Capability | LangSmith | Runback | Note |
|---|---|---|---|
| Read and search traces | ✓ | ✓ | |
| Dataset and eval management | ✓ | ✓ | |
| Re-execute any step from captured inputs | ✗ | ✓ | Runback's core capability — bisect in log₂ tries |
| CI release gate — policy blocks the deploy | ✗ | ✓ | |
| Signed, tamper-evident audit export | ✗ | ✓ | SHA-256 chain; verify without Runback |
| Self-host, data never leaves your perimeter | partial | ✓ | A full deployment exists, but it's Enterprise-tier only, license-gated, and some features (Hub, cloud-model evaluators) stay cloud-only |
| Regulatory mappings (EU AI Act · CPS 230 · NIST) | partial | ✓ | Publishes an EU AI Act capability crosswalk; no CPS 230 or NIST AI RMF mapping |
| Redact PII/secrets automatically, on by default | partial | ✓ | LangSmith's Python/TS SDKs ship a create_anonymizer() toolkit (regex, custom functions, or Presidio/Comprehend) — capable, but nothing is redacted unless you write the patterns yourself, and it isn't available in LangSmith's Go SDK. Runback's TS, Python, and Go SDKs all redact in-process with working detectors on by default |
| One flat price — no separate compute/storage units | ✗ | ✓ | LangSmith bills across four axes: seats, base traces, LangChain Compute Units ($1.50/unit), and LangChain Storage Units ($1.00/unit) — plus a paid upgrade for extended (400-day) retention. Runback is one tier: seats + runs + retention, bundled |
| Purpose-built Go SDK, not just a generated REST client | partial | ✓ | LangSmith's Go package is Stainless-generated REST API bindings plus a bare OpenTelemetry tracer — no traceable()-style ergonomics and no anonymizer. Runback's Go SDK has the same manual-recording shape (and redaction) as its TS/Python SDKs |
It shows what happened. It can't re-execute the step, gate your CI pipeline, or produce a signed audit record. Most teams use both — LangSmith for what it's already good at, Runback for the incident replay, CI gate, and signed record it doesn't do.
Compiled from LangSmith's public documentation at https://docs.smith.langchain.com/, 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 Products change; if a row is out of date or wrong, tell us at legal@runback.dev and we will correct it.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.
No signup. Walk a failing production run step by step and see what the model saw.