Both trace multi-step agents, run experiments, score live traffic and route traces to human reviewers. Opik is open source with a published self-serve price ladder; HoneyHive is a hosted platform aimed at enterprise and regulated buyers, with everything above the free tier sold through sales. Buying process and hosting decide most of this.[1][4]
The difference between HoneyHive and Opik is licence and how you buy: HoneyHive is a hosted, proprietary agent observability and evaluation platform built on OpenTelemetry, with a free developer tier and quote-based Enterprise, which is also the only route to self-hosting. Opik, from Comet, covers similar ground under Apache-2.0, with free self-hosting and a $19-a-month cloud tier. Both trace agents, score production traffic and version prompts.
| Decision factor | HoneyHive | Opik |
|---|---|---|
| Ownership | Independent; $7.4M raised in total, last announced April 2025 | Comet ML, independent; reports $70M in total funding |
| Licence | Proprietary platform; SDKs and tools are MIT | Apache-2.0 for the core platform and SDKs |
| Self-hosting | Enterprise only; full or hybrid, documented on AWS | Free; all features except user administration |
| OpenTelemetry | Built on it; reads GenAI, OpenLLMetry and OpenInference conventions | OTLP over HTTP only; conventions not stated |
| Native SDKs | Full tracing SDK in Python; TypeScript is a REST client | Python, TypeScript, Java and .NET |
| Run-time checks | None; it observes and scores | Partial: guardrails your code calls; they fail closed |
| Free tier | Developer: 10,000 events a month, 30-day retention, 5 users | Free Cloud: 25k spans a month, 60-day retention, 10 members |
| First paid tier | No published self-serve plan; Enterprise by quote | Pro Cloud: $19 a month for 100k spans |
| Capability | HoneyHive | Opik | 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 | — | Partial | — |
| Licence and deployment | |||
| Open source | Partial | ✓ | Partial |
| Self-hosting | ✓ | ✓ | Partial |
HoneyHive's Developer tier is free with no card: 10,000 events a month, 30-day retention, up to five users and one workspace, on multi-tenant SaaS in AWS us-west-2. Above that there is no published self-serve plan; Enterprise is quote-based and offers dedicated single-tenant hosting, a hybrid set-up with your own data plane and a HoneyHive-run control plane, or a fully self-hosted deployment in your AWS account. Self-hosting is documented on AWS EKS only.
Opik takes the opposite approach. The Apache-2.0 release is free to self-host with every feature except user administration, Kubernetes is the documented production path, and the hosted cloud has a free tier and a $19 Pro tier you can buy without talking to anyone. Enterprise adds on-premises or fully hosted deployment, SSO and support with a two-hour response SLA.
On the companies themselves: HoneyHive is independent, with $7.4M in total funding last announced in April 2025, and in June 2026 it was named observability partner in Microsoft's ASSERT announcement. Comet, which builds Opik, is independent and reports $70M in total funding.
HoneyHive is built on OpenTelemetry. It accepts OTLP, reads the OTel GenAI, OpenLLMetry and OpenInference conventions, and works with your own instrumentors and an OpenTelemetry Collector. Its full tracing SDK is Python; the TypeScript package is a REST API client rather than an auto-instrumenting tracer, so TypeScript teams usually send OTLP instead. Integrations reach into enterprise platforms such as Salesforce Agentforce, Databricks Agent Bricks and Microsoft Copilot Studio.
Opik accepts OTLP over HTTP only and does not state which conventions it reads, but ships native SDKs for Python, TypeScript, Java and .NET. Teams with Java or .NET agents get a first-party SDK in Opik; teams with existing OpenInference or OpenLLMetry instrumentation get documented convention support in HoneyHive. Both track coding agents: HoneyHive traces Claude Code, Codex CLI and Devin sessions, and Opik's Cost Intelligence tracks spend for Claude Code and Codex.
The evaluation features line up closely. HoneyHive runs experiments with evaluate() against datasets, gates CI with GitHub Actions, and scores sampled production traces with LLM, code and human evaluators, with default sampling lowered to 10% in May 2026. Annotation queues gained automations in April 2026, and Agent Graph, Trajectory, Thread and Conversation views help read multi-agent runs. Opik offers experiments, Test Suites, online rules with more than 30 built-in metrics or custom Python metrics, annotation queues that fill automatically, and a Prompt Optimizer that HoneyHive does not list.
Neither offers approval holds. HoneyHive documents no blocking or guardrails on live agent actions; its Policies feature sets organisation-wide evaluation and monitoring standards, and in the Microsoft partnership HoneyHive observes while Microsoft's specification enforces. Opik's guardrails run as a blocking call in your code that fails closed, with English-only PII and topic checks.
As of 20 October 2026, HoneyHive's free Developer tier covers 10,000 events a month, and anything beyond needs an Enterprise quote. Opik's Free Cloud covers 25k spans a month for up to 10 members with 60-day retention, and Pro Cloud is $19 a month for 100k spans and up to 50 members, then $5 per 100k. Events and spans are not defined identically, so measure your own traffic.
For a team that expects to outgrow 10,000 events, the practical question is whether a sales conversation is acceptable early on. HoneyHive's Enterprise tier brings custom limits and retention, unlimited users and workspaces, SAML SSO, an SLA, a custom DPA and BAA, and data residency. Opik's Enterprise plan is also custom, with unlimited users, SSO and service accounts, but a team can run on Pro Cloud for some time before it needs one. See HoneyHive's pricing and Opik's pricing.
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 can act on a failing score through runtime policies, approval holds and a kill switch for a run, an agent or a team. HoneyHive observes and scores without blocking; Opik's guardrails block only where your code calls them, and neither has approval holds. Prefactor has no prompt playground or prompt registry and its platform is hosted, so for prompt iteration or free self-hosting, Opik is the better fit. 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.