Both trace agents, run offline and online evals, queue traces for human review and version prompts. Braintrust centres on experiments, an in-product analysis agent and a gateway; Confident AI centres on DeepEval's metric library, with red teaming and simulation on top. How your team prefers to write evals usually decides it.[1][4]
Braintrust and Confident AI are both hosted, proprietary evaluation platforms with open-source scoring libraries; the difference is where the work starts. Braintrust is organised around experiments in its UI, with Loop, an analysis agent, and a gateway in preview. Confident AI is organised around DeepEval, an Apache-2.0 metrics framework you run in code and CI, plus red teaming and conversation simulation. Neither blocks a live agent action.
| Decision factor | Braintrust | Confident AI |
|---|---|---|
| Ownership | Independent; $80M Series B in February 2026 | Independent; Y Combinator Winter 2025 company |
| Open-source pieces | SDKs, Autoevals scorer library, Terraform modules | DeepEval metrics framework and confident-trace SDK (Apache-2.0) |
| Centre of gravity | Experiments in the UI, with the Loop analysis agent | Metrics in code: 40+ DeepEval metrics run locally and in CI |
| Self-hosting | Enterprise only; data plane only, Braintrust runs the control plane | Enterprise only; platform on your AWS, GCP or Azure Kubernetes with a licence key |
| Gateway | Hosted gateway in public preview, no SLA | None; traces through third-party gateways such as LiteLLM and Portkey |
| Red teaming and simulation | Not documented | Yes: red teaming, multi-turn and voice simulation |
| Free tier | Starter: 1 GB processed data, 10K scores, 14-day retention | Free: 2 seats, 1 GB-month of trace data, 5 test runs a week |
| First paid tier | Pro: $249 a month, unlimited users | Starter: $200 a month per organisation, unlimited seats |
| Capability | Braintrust | Confident AI | 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 | Partial |
Braintrust's product starts from the experiment. You bring a dataset, a task and scorers, run variants from the SDK, CLI or UI and compare them. Loop, its in-product agent, reads project data, writes scorers and runs evals, and since September 2026 Patterns and Topics group production behaviour for review. Several of those newer features are in public preview.
Confident AI starts from the metric. DeepEval, its open-source framework for Python and TypeScript, ships more than 40 metrics covering agents, multi-turn conversations, RAG, MCP and multimodal output, and runs test cases locally or in CI/CD much like unit tests. The hosted platform stores those test runs, datasets and regression reports, and adds online evals, annotation queues and Prompt Studio.
A team that likes to iterate in a UI with an assistant suggesting changes will find Braintrust's loop quicker. A team that wants evals as code next to its tests, with a library it can read and extend, will be more at home with DeepEval.
Human review and prompts differ in the detail. Braintrust supports categorical, continuous and free-form review scores with assigned, blind and required reviews, but its free Starter plan allows only one human review score per project. Confident AI has annotation queues for traces, spans, threads and test cases, multi-reviewer forms and alignment between metric and human scores. For prompts, Braintrust offers versioned templates in Mustache or Nunjucks, environments and calls from code or REST without redeploying; Confident AI's Prompt Studio has commits, versions and environment labels, and compares prompt versions and models side by side.
The extras point in different directions. Braintrust runs a gateway that gives one API to OpenAI, Anthropic, Google, AWS and others with caching and logging; the hosted version is in public preview, free and without an SLA, and it replaced the earlier AI proxy. Confident AI has no gateway of its own and traces through LiteLLM, Portkey, OpenRouter, Bifrost or TrueFoundry instead.
Confident AI puts more into testing before release. It offers red teaming with trace-level detections, multi-turn and voice simulation, and since October 2026 Journeys (beta) for simulating user paths through voice connections such as Pipecat, LiveKit and SIP. Red teaming and the compliance modules sit on the Enterprise plan.
Both also expose their platforms to coding agents. Braintrust ships a bt CLI and an MCP server, and Confident AI has an MCP server and a V2 REST API with more than 200 endpoints, released in September 2026. If you want an assistant to query traces or run evals for you, both support it.
Neither platform is open source, and both reserve self-hosting for Enterprise. Braintrust lets you run the data plane in your own AWS, GCP or Azure account, but it always operates the control plane, including the UI and authentication. Confident AI's self-hosting guide deploys its platform to your own Kubernetes cluster on AWS, GCP or Azure with Terraform and Helm, using private container images and a signed licence key.
If a compliance review asks where logins and metadata live, that difference matters. Confirm the exact boundary with each vendor before trialling.
As of 20 October 2026, Braintrust charges a platform fee plus processed data and scores. Starter is free with 1 GB processed, 10K scores and 14-day retention; Pro is $249 a month with 5 GB, 50K scores and 30-day retention. Every plan has unlimited users. Confident AI charges per organisation with trace storage in GB-months: Free covers 2 seats and 1 GB-month, Starter is $200 a month with unlimited seats and 5 GB-months, and Team is $2,000 a month with 75 GB-months, SSO and a SOC 2 report. Extra storage is $1 per GB-month.
Braintrust meters scores, so heavy online scoring adds cost; Confident AI meters stored trace data, and its free tier drops spans above 1 GB-month. Model both against Braintrust's pricing and Confident AI'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 acts on what it finds through runtime policies, approval holds and a kill switch scoped to a run, an agent or a team. Neither Braintrust nor Confident AI documents that: Braintrust's online scoring and alerts judge traces after logging, and Confident AI's threshold checks run on recorded data over a 24-hour window. Prefactor has no prompt playground or prompt registry and its platform is hosted, so if prompt iteration or a large open-source metric library is the priority, Braintrust or Confident AI 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.