Feature lists overlap: tracing, experiments, online scoring, human review and prompt versioning. Braintrust is the self-serve, experiment-first option with published tiers and broad SDKs; HoneyHive is the OpenTelemetry-first option that can run entirely in your cloud on an Enterprise contract.[1][4]
Braintrust and HoneyHive are both hosted, proprietary platforms for tracing and evaluating agents, and both are independent. The differences are in buying and hosting: Braintrust publishes a $249 a month Pro plan but only lets Enterprise customers host the data plane, while HoneyHive has no self-serve paid plan but can run fully inside your own AWS account on Enterprise. Neither can block a live agent action.
| Decision factor | Braintrust | HoneyHive |
|---|---|---|
| Ownership | Independent; $80M Series B in February 2026 | Independent; $7.4M total funding last announced April 2025 |
| Self-hosting | Enterprise only, data plane only; Braintrust runs the control plane | Enterprise only; fully self-hosted or hybrid, documented on AWS |
| Centre of gravity | Experiments, with the Loop agent analysing results | OpenTelemetry traces, online evals and monitoring |
| SDKs | TypeScript, Python, Go, Java, Ruby, C# | Python tracing SDK; TypeScript REST client; OTLP for others |
| Gateway | Braintrust Gateway, public preview, no SLA | None; integrates with third-party gateways |
| Users on the free tier | Unlimited | Up to 5 |
| Free tier | Starter: 1 GB processed data, 10K scores, 14-day retention | Developer: 10,000 events a month, 30-day retention |
| First paid tier | Pro: $249 a month | No self-serve paid plan; Enterprise is quote-based |
| Capability | Braintrust | HoneyHive | 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 | — | — | ✓ |
| Gateway or proxy in the request path | ✓ | — | — |
| Licence and deployment | |||
| Open source | Partial | Partial | Partial |
| Self-hosting | Partial | ✓ | Partial |
For teams with data-residency requirements this is usually the first filter. Braintrust's Enterprise plan lets you run the data plane in your own AWS, GCP or Azure account, or have Braintrust run it there as BYOC. The control plane, meaning the UI, authentication and metadata, is always operated by Braintrust, and no fully self-contained deployment is documented.
HoneyHive's Enterprise plan offers two shapes: fully self-hosted, with both control plane and data plane in your environment, or hybrid, with your data plane and HoneyHive's control plane. Both are documented on AWS EKS with Terraform and Helm. If your review requires the whole product inside your account, HoneyHive can do that; Braintrust cannot. If you run on GCP or Azure, Braintrust documents those and HoneyHive does not.
Braintrust's product is organised around the experiment: a dataset, a task and scorers, run from the SDK, CLI or UI and compared side by side. Scorers can be LLM judges, code in TypeScript or Python, or pre-built judges from the open-source Autoevals library. Its Loop agent reads project data, writes scorers and runs evals, and since September 2026 Patterns and Topics group production behaviour for review. Several of these newer features are in public preview.
HoneyHive starts from OpenTelemetry traces and builds evaluation on top. Experiments run with evaluate() against datasets and can gate pull requests in GitHub Actions. Online evaluations score sampled production traces with LLM, code and human evaluators; the default sample rate dropped to 10% in May 2026. Annotation queues route flagged traces to domain experts, and its Policies feature lets an organisation set evaluation and monitoring standards across teams.
SDK coverage differs sharply. Braintrust ships SDKs in six languages. HoneyHive's full tracing SDK is Python; for TypeScript it offers a REST client and points you to OTLP.
Release history shows where each is putting its effort. Braintrust's October 2026 changes included pattern severity, PagerDuty notifications, a thread view, SQL charts and a coding-agent cost dashboard, several in public preview, and in September it added application logs beside traces and blind reviews. HoneyHive added dataset tools with data plane API keys in October, a Conversation view in September, and Salesforce Agentforce and Databricks Agent Bricks tracing in August. With Braintrust, check which features you rely on are still in preview; with HoneyHive, whose last announced funding was $7.4M in April 2025, ask about the company's plans during procurement.
As of 20 October 2026, Braintrust's Starter plan is free with 1 GB of processed data, 10K scores and 14-day retention, then $4 per GB and $2.50 per 1,000 scores. Pro is $249 a month with 5 GB, 50K scores and 30-day retention. Every Braintrust plan includes unlimited users, projects and experiments, though Starter allows only one human review score per project.
HoneyHive's Developer tier is free with 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 price; Enterprise is quoted. A team that wants to start paying by card next week has a clear path with Braintrust and none with HoneyHive. See Braintrust's pricing and HoneyHive's pricing.
Braintrust's online scoring, alerts and Patterns judge traces after they are logged; Loop asks for approval only for its own edits inside Braintrust. Its Gateway, in public preview, routes and logs model calls but is not documented as a policy layer. HoneyHive documents no blocking or approvals either, and in Microsoft's Agent Control Specification partnership it is described as the observability layer while another component enforces. If your agent issues refunds or changes records, plan how a failing score will reach the agent before it repeats the mistake.
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. Neither Braintrust nor HoneyHive documents run-time controls of that kind. Prefactor has no prompt playground or prompt registry and its platform is hosted, so if prompt iteration or running everything in your own AWS account is the requirement, Braintrust or HoneyHive is the better pick. 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.