LangSmith and NexArt address different accountability layers. LangSmith optimises for operator-facing observability, traces, evals, prompt versions, latency and cost. NexArt produces an evidence layer, tamper-evident Certified Execution Records with an independent signature that anyone can verify without a LangSmith account or access to your infrastructure. Teams building on LangChain typically keep both.
Side-by-side comparison
| Dimension | LangSmith (observability) | NexArt (execution evidence) |
|---|---|---|
| Audience | Internal engineering and QA | Auditors, regulators, customers, legal |
| Integrity | Trust the LangSmith database | SHA-256 canonical hash + Ed25519 signature from the NexArt attestation node |
| Third-party verification | Requires LangSmith account access | Offline verification with a published public key |
| Retention | Tier-based, mutable, samplable | Portable JSON artifact controlled by the record holder |
| Data exposure | Stores raw prompts, tool calls, outputs | Confidential mode stores only cryptographic commitments |
| Answers 'debug this run' | Yes | Not the goal |
| Answers 'prove this run to a regulator' | No | Yes |
Recommended architecture
For a LangChain or LangGraph agent, wrap the outer invocation boundary with a NexArt certification call and keep LangSmith tracing enabled inside. The result: engineering keeps its debugging surface, compliance and customers get a portable, tamper-evident record of every executed run.
A common pattern: send everything to LangSmith for internal iteration; certify only regulated or high-stakes runs through NexArt to control cost. Both layers see the same execution.
Frequently asked
Do I have to pick between LangSmith and NexArt?
No. They solve non-overlapping problems. LangSmith is for the operator; NexArt is for anyone the operator has to answer to. Most regulated teams run both.
Can NexArt verify a run that was traced in LangSmith?
Verification does not depend on LangSmith at all. A NexArt Certified Execution Record is a self-contained JSON artifact that anyone can verify offline using the attestation node's public key. LangSmith is not in the verification path.
Add verifiable execution to your AI stack
Produce Certified Execution Records anyone can verify without access to your infrastructure.
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