Both cover tracing, offline and online evals, annotation queues and prompt versioning. HoneyHive suits teams that want an OpenTelemetry-first platform across many frameworks and enterprise agent builders, and expect to buy through sales; LangSmith suits teams on LangChain or LangGraph who want to start free and pay per seat.[1][4]
HoneyHive is a hosted, OpenTelemetry-based agent observability and evaluation platform with a free tier and Enterprise-only paid plans, while LangSmith is LangChain's platform with self-serve per-seat plans and the deepest LangChain and LangGraph integration. Feature for feature they are close: both trace agents, run offline and online evals, queue runs for human review and version prompts. How you buy, and which frameworks you use, usually decides it.
| Decision factor | HoneyHive | LangSmith |
|---|---|---|
| Ownership | Independent; $7.4M total funding announced April 2025 | LangChain, independent; $125M Series B in October 2025 |
| Instrumentation | Built on OpenTelemetry; OTel GenAI, OpenLLMetry and OpenInference conventions | SDK decorators and framework integrations; also ingests OTLP |
| Tracing SDKs | Full tracer in Python; TypeScript package is a REST client | Python, TypeScript, Go and Java |
| Run-time controls | None; Policies set evaluation and monitoring standards | Partial: LLM Gateway (beta) caps spend, restricts models and redacts model calls |
| Self-hosting | Enterprise only, fully self-hosted or hybrid, documented on AWS | Enterprise add-on on Kubernetes; BYOC also Enterprise |
| Free tier | Developer: 10,000 events a month, 30-day retention, up to 5 users | Developer: 1 seat, 5k base traces a month, 14-day retention |
| First paid tier | None published; Enterprise is quote-based | Plus: $39 per seat a month, 10k base traces |
| Capability | HoneyHive | LangSmith | Prefactor |
|---|---|---|---|
| Observe | |||
| LLM call tracing | ✓ | ✓ | ✓ |
| Multi-step agent tracing (tool calls, nested spans) | ✓ | ✓ | ✓ |
| Cost tracking | ✓ | ✓ | ✓ |
| OpenTelemetry support | ✓ | ✓ | ✓ |
| Evaluate | |||
| Offline evals (datasets, experiments) | ✓ | ✓ | ✓ |
| Online evals on production traffic | ✓ | ✓ | ✓ |
| LLM-as-a-judge scoring | ✓ | ✓ | ✓ |
| Code-based evaluators | ✓ | ✓ | ✓ |
| Human review and annotation | ✓ | ✓ | ✓ |
| Prompt versioning and playground | ✓ | ✓ | — |
| Act on findings | |||
| Runtime controls on live agent actions | — | Partial | ✓ |
| Gateway or proxy in the request path | — | — | — |
| Licence and deployment | |||
| Open source | Partial | Partial | Partial |
| Self-hosting | ✓ | ✓ | Partial |
This is the most practical difference. HoneyHive's Developer tier is free with no card for 10,000 events a month, 30-day retention and up to five users, which is more generous on users and retention than LangSmith's free tier. Beyond it there is no published self-serve plan: anything larger is an Enterprise contract priced by quote.
LangSmith has a self-serve ladder. Developer is free for one seat, Plus is $39 per seat a month, and Enterprise adds SSO, role-based access and self-hosting. A small team that wants to grow usage without a sales call can do that on LangSmith and cannot on HoneyHive.
Company size is part of the picture. HoneyHive's last announced funding was $7.4M in total, in April 2025. LangChain raised a $125M Series B in October 2025. Neither has announced an acquisition.
For a pilot, HoneyHive's free tier is the easier place to start with a few colleagues, since five users can share it. The question to settle early is what the Enterprise contract will cost once the pilot works, because there is no published price to plan against.
HoneyHive is built on OpenTelemetry and reads OTel GenAI, OpenLLMetry and OpenInference conventions, with a bring-your-own-instrumentor option and a Collector integration. It traces a wide spread of builders, including Salesforce Agentforce, Databricks Agent Bricks, Microsoft Copilot Studio, n8n, and coding agents such as Claude Code, Codex CLI and Devin. In June 2026 Microsoft named it the observability partner in its Agent Control Specification announcement.
LangSmith also ingests OTLP and maps OpenInference and OpenLLMetry attributes, but its deepest integration is with LangChain, LangGraph and Deep Agents, which the same company builds. Its SDKs cover Python, TypeScript, Go and Java. HoneyHive's full tracing SDK is Python; in TypeScript you use its REST client or plain OTLP. A TypeScript-heavy team will find LangSmith easier to instrument.
Both also read coding agents now. HoneyHive added session traces, usage and spend analysis for Claude Code and Devin in June 2026. That is a narrower use case, but relevant if your engineering team wants one place for both product agents and coding agents.
HoneyHive observes and scores; it does not block, hold or approve live agent actions. Its Policies feature sets organisation-wide evaluation and monitoring standards, not run-time enforcement, and in the Microsoft partnership HoneyHive is the observability layer while the specification handles enforcement. LangSmith's LLM Gateway, in public beta since 30 July 2026, can cap spend, restrict models and redact personal data in model calls, but not tool calls.
For evaluation the two are close. HoneyHive runs LLM, Python code and human evaluators on sampled production traces, gates releases in CI through GitHub Actions, and routes flagged traces to annotation queues with automations. LangSmith runs LLM-as-judge, pairwise and code evaluators offline and online, with annotation queues, rubrics and required reviewer counts.
If you need a check that stops an action, neither product provides it on tool calls today, so plan that layer separately whichever one you choose.
As of 20 October 2026, HoneyHive prices on events, with a free tier and custom Enterprise pricing only. LangSmith prices per seat plus traces: Developer is free for one seat and 5k base traces a month, Plus is $39 per seat a month with 10k base traces, and the per-trace overage rate is not published. Self-hosting is Enterprise only on both. Check HoneyHive's pricing and LangSmith's pricing against your own volumes.
Retention also differs on the free tiers: 30 days for HoneyHive and 14 days for LangSmith base traces. HoneyHive's free tier runs on multi-tenant SaaS in a single AWS US region; LangSmith offers US, EU and APAC regions.
We sell the layer this section describes. Read it with that in mind.
Stated plainly, since Prefactor publishes this page: Prefactor is an agent evaluation platform that scores each step of a run and acts on what it finds through runtime policies on tool calls and data access, approval holds for risky actions, and a kill switch for a run, an agent or a team. HoneyHive has no run-time controls, and LangSmith's gateway covers model calls only. Prefactor has self-serve paid plans, but it has no prompt playground or prompt registry, and its platform is hosted. See the full comparison of 15 platforms.
Reviewed against public product and documentation pages on October 20, 2026. If a vendor has changed a feature, product name, or positioning since then, send a correction and we will update it. Numbered source links in the page body point to the ordered sources below.
Prefactor scores each step of every agent run and can hold or stop an action when a score says it should not happen. Start on the free tier: 5,000 spans a month, no credit card required.
Prefactor helps teams observe, evaluate, and improve their AI agents in production, across every framework and provider.