Alternatives · Braintrust
6 best Braintrust alternatives in 2026
Braintrust is an eval and observability platform with CI checks, Topics, and Patterns. Its own pricing and docs show why teams shop around. The free Starter plan keeps logs for 14 days, and the next plan is Pro at $249 a month. Usage is measured at ingestion, so deleting logs does not lower it. Self-hosting is Enterprise only, and Braintrust still runs the control plane. Topics, which groups your traces, must be turned on in each project by an organization owner. three.dev needs no setup. Here is what each alternative is best for, what it costs, and where each one beats Braintrust.
Bryan Lee, Product LeadUpdated · 16 min read
Quick comparison: the best Braintrust alternatives
| Tool | Best for | Starting price | Key difference from Braintrust | Review |
|---|---|---|---|---|
| 01three.dev | Teams with a live AI feature and a coding agent, and no time to write evals | Free; paid from $79 a month | Finds and ranks failures by severity with nothing to turn on. Paid plans from $79 a month. | Read the three.dev review |
| 02Langfuse | Braintrust users who want open source, a plan between free and $249, or every part on their own servers | Free; Core $29 a month | MIT core, free to self-host, and cloud plans from $29 a month. You write the judges. | Read the Langfuse review |
| 03LangSmith | LangChain and LangGraph teams that want issue fixes drafted as pull requests | Free for 1 seat; Plus $39 per seat a month | Priced per seat. Engine drafts fix pull requests on Plus and Enterprise. | Read the LangSmith review |
| 04Raindrop | Teams that care more about production alerts than eval workflows | Free; Pro $299 a month plus usage | Monitoring and alerts for agents. Issue Detection is on Pro, at $299 a month plus usage. | Read the Raindrop review |
| 05Arize Phoenix | Eval-heavy teams that want CI gates on open source they run themselves | Phoenix free to self-host; Arize AX Pro $50 a month | Free to self-host. Hosted Arize AX Pro costs $50 a month. | Read the Arize Phoenix review |
| 06Opik | Teams that want Apache 2.0 open source and a cloud plan far below $249 | Free; Pro $19 a month | Apache 2.0 and a $19 cloud plan. Diagnostics groups repeated failures on Ollie credits. | Read the Opik review |
| ··Braintrust | Teams that want evals and CI checks to decide what ships | Free; Pro $249 a month | The tool you are comparing against. |
1. three.dev
three.dev scores a sample of your live LLM traffic in the background and groups the failures into named failure modes, each with a severity. Braintrust's Topics and Patterns find problems too, once someone turns them on in each project, and they draw on model credits. three.dev starts when the first requests arrive, and scoring comes with the plan. Paid plans start at $79 a month, between Braintrust's free Starter and $249 Pro. Your coding agent reads each failure mode over the three.dev MCP server and proposes the fix.
Failure modes
Failures group into failure modes, ranked by importance and frequency.
A failure mode table counts up, each row gets a severity, and the rows sort by severity. Wrong refund window is High and leads with 386 of 8,124 scored requests. Invented discount code is Medium and climbs above Unrequested bullet lists, which is Low, though it has fewer failures.
Where it is strong
- No project switch, Owners-group permission, or facet summaries to wait for. Issues appear as requests are scored and group into failure modes once enough collect.
- You control what scoring uses: every request is scored at first, and you can turn sampling down to 10% and cap it per day.
- three.dev sets each failure mode's severity, and your team can change it, describe a new failure mode in plain language, split or merge failure modes, or dismiss one.
- Each issue says why the request failed and quotes the lines behind it.
Where it falls short
- No evals, datasets, scorers, experiments, or CI checks. If evals gate your releases, keep Braintrust for them.
- No alerts to Slack, webhooks, or PagerDuty.
- A hosted proxy at gate.three.dev, with no self-hosted or BYOC option. It is not open source.
- It records LLM calls and the tool calls the model asks for, without separate spans for tool runs or retrieval. Not for health data (PHI) or government workloads yet.
- Pricing
- Free is $0 with 1 GB of data (about 50,000 requests) and 5k scored requests a month. Starter is $79 a month with 5 GB and 10k scored requests, then $3 per GB and $2.50 per 1k scored. Pro is $249 a month with 20 GB and 25k scored requests, then $2 per GB and $1.50 per 1k scored. Every plan includes scoring and unlimited seats.
- Choose it over Braintrust if
- you want failures found and ranked with nothing to turn on, a paid plan from $79 a month, and your coding agent making the fix.
Why teams choose three.dev
"Using three.dev has been a huge leap for us in providing our users the highest quality while maintaining fast responses."
Don PottingerCo-founder and CTO, LanguaTalkRead the case studythree.dev vs Braintrust
| Feature | three.dev | Braintrust |
|---|---|---|
| What it is | Failure-mode discovery for live AI features, with the fix handed to your coding agent | An eval and observability platform: tracing, datasets, scorers, experiments, CI checks, prompts, alerts, and Loop |
| How you connect | Swap your base URL for gate.three.dev and add a three.dev API key and one header. No SDK to add. | SDKs for TypeScript, Python, Go, Java, Ruby, and C#, OpenTelemetry, or the Braintrust Gateway (public preview). |
| Setup before you see failures | None. Scoring starts on your live traffic. | Topics: a member of the Owners group turns it on in each project, traces must render in the Thread view, and clusters appear after 100 facet summaries. Patterns: someone who can create automations turns it on in each project. |
| Grouping failures | Issues group into named failure modes on their own, each with a severity, most severe first. | Topics clusters traces daily by task, sentiment, issues, and custom facets, ranked by share. Patterns (public preview) runs Loop daily and ranks recurring problems by severity and frequency. |
| Shaping the list | three.dev sets the severity; your team can change it, describe a new failure mode in plain language, split or merge failure modes, or dismiss one. | Custom facets you write with your own prompt (Topics). Pattern severity and category rubrics can be customized (October 2026). |
| Asking about your traffic | Chat answers questions in plain words and links each answer to the requests behind it. | Loop investigates logs, experiments, and datasets, and can create scorers, prompts, and datasets with your approval. |
| Coding-agent hand-off | The MCP server hands over a named failure mode, its failing requests, and why each one failed. A Fix with your agent button copies the prompt. | Patterns' Copy for agent brief, a hosted MCP server, the bt CLI, and Loop pull requests on GitHub (public preview). |
| Checking a fix | Tag requests with a release and compare releases or date ranges on quality, latency, and cost. | Experiments on datasets, and a GitHub Action that posts eval results on each pull request and can gate merges. |
| Evals, prompts, datasets | Not offered today | Yes, on every plan |
| Alerts | Not offered today | Alerts to Slack, webhooks, or PagerDuty, plus Slack alerts for each new pattern |
| What it costs to find failures | Scoring is included in the plan price. | Topics and Loop run on monthly model credits ($10 on Starter, $100 on Pro) that do not roll over. |
| History kept | 30 days on Free, 90 on Starter, 180 on Pro | Logs 14 days on Starter and 30 days on Pro, extendable to 180 days at a storage charge; up to 365 days on Enterprise |
| Data and compliance | Not for health data (PHI) or government workloads yet. three.dev does not train models on your traffic for anyone else. | A click-through DPA on Pro. SAML SSO, audit logs, SOC 2 attestation, and a BAA on Enterprise. |
| Open source and self-hosting | Hosted proxy at gate.three.dev | Platform not published as open source. Self-hosting and BYOC on Enterprise, with Braintrust running the control plane. |
| Price | Free plan; Starter $79, Pro $249 a month. Scoring included. Unlimited users. | Starter free; Pro $249 a month; Enterprise custom. Unlimited users. |
What you gain moving from Braintrust
- Failure modes found for you, with no project switch, owner permission, or facet summaries to wait for
- A paid plan at $79 a month, between free and $249
- Scoring included in every plan, with no monthly model credits to track
- A severity on every failure mode that your team can change, plus failure modes you can create, split, merge, or dismiss
What you give up
- Evals, datasets, experiments, and CI checks on pull requests
- Prompts, and Loop drafting scorers and opening pull requests
- Alerts to Slack, webhooks, or PagerDuty
- Self-hosting the data plane on Enterprise, and full traces of tool runs and retrieval steps
2. Langfuse
Langfuse is an open-source platform for agent tracing, evals, prompt management, datasets, and experiments. Its MIT core self-hosts for free, and no part of it has to stay with a vendor. Langfuse Cloud has a $29 Core plan, between Braintrust's free Starter and $249 Pro. Judges run on your own LLM connection. Langfuse has no counterpart to Topics or Patterns in general release: its own Topics is "In progress" on the roadmap and in a closed beta on Langfuse Cloud in October 2026.
Where it is strong
- Self-host the MIT core for free. It can run fully offline, and the free build includes Enterprise SSO and RBAC.
- Core is $29 a month with 90 days of data, where Braintrust goes from free to $249.
- Judges and evaluators run on your own LLM connection, so you pick the model that scores your traffic.
- Every plan, Hobby included, has prompt versioning, datasets, and experiments, and a GitHub Action runs experiment checks in CI.
Where it falls short
- Automatic grouping (Topics) is in closed beta for allowlisted Cloud projects. Today you cluster failures by hand or ask Halo.
- Each judge is a prompt you write and test, and each score is a billable unit on top of the model call.
- Evaluators score one observation at a time and do not read sibling or child spans.
- Hobby allows 2 users and 2 alerts. On Cloud, SSO and fine-grained RBAC need Pro plus the $300-a-month Teams add-on, or Enterprise.
- Pricing
- Langfuse Cloud bills units: any trace, observation, or score. Hobby is free with 50k units and 30 days of data. Core is $29 a month and Pro $199, each with 100k units, then $8 per 100k, falling to $6 above 50M. Enterprise is $2,499 a month. Self-hosting the MIT core is free.
- Choose it over Braintrust if
- you want open source on your own servers, or a cloud plan well under $249 a month, and you are ready to write your own judges.
3. LangSmith
LangSmith is LangChain's agent engineering platform: tracing, online and offline evals, prompts, alerts, and deployment. Braintrust puts evals first; LangSmith pairs them with Engine. On Plus and Enterprise, Engine scans production traces on a schedule, groups failures into issues ranked by severity, drafts prompt and code fixes as GitHub pull requests or GitLab merge requests, and watches CI on the changes it opens. Braintrust's Loop can open GitHub pull requests too, in public preview.
Where it is strong
- Engine opens fix pull requests on GitHub or GitLab, ready for review, and pushes revisions when its own CI checks fail.
- Native tracing for LangChain and LangGraph, from the team that makes them.
- Multi-turn online evaluators score a whole conversation once it goes idle.
- Deployment is part of the platform, and Plus includes one free small serverless deployment.
Where it falls short
- Plus costs $39 per seat a month, invited users included, so a team of seven pays $273 a month before usage.
- Closed source. Self-hosting is an Enterprise add-on.
- Engine bills about 7 to 45 usage units of $1 per run, on top of seats and traces, with a default cap of 750 units a month.
- Base traces keep 14 days, and online evaluators upgrade matching traces to 180-day retention, at a charge, by default.
- Pricing
- Developer: free, 1 seat, 5k base traces a month. Plus: $39 per seat a month with 10k base traces, then $0.005 per trace. Engine: usage units at $1 each, billed on top. Enterprise: custom, with self-hosted and hybrid options.
- Choose it over Braintrust if
- your app runs on LangChain or LangGraph, you want fixes drafted as pull requests by the vendor that runs your tracing, and your team is small enough for per-seat pricing.
4. Raindrop
Raindrop is a monitoring platform for AI agents that works the way Sentry does for web apps. Braintrust is built around evals; Raindrop is built around production monitoring. Signals track behaviors you describe in plain language or pick from presets, and alerts post to Slack when a signal crosses a threshold. On Pro, Issue Detection looks for new breakage patterns, failures spreading across users, and regressions after a deploy, and gives each issue a severity and a trend. Raindrop Pro costs more than Braintrust Pro.
Where it is strong
- Pro keeps data with no retention limit, where Braintrust Pro keeps logs 30 days.
- Experiments compare cohorts of production events and measure how signal rates change.
- Preset signals for user frustration, task failure, forgetting, refusals, jailbreaks, NSFW content, and praise.
- Issue Detection shows how each issue trends over time and flags regressions after a deploy.
Where it falls short
- Pro costs more than Braintrust Pro: $299 a month plus $0.003 per event up to 1M.
- Issue Detection, Stumbles, and Experiments are Pro only, and Hobby stops recording after 1,000 events in a month.
- Custom signals are capped: 1 on Hobby, 10 on Pro.
- Hosted, with self-hosting in your own cloud in beta.
- Pricing
- Raindrop meters events. One event is a user message and the agent's response, including tool calls and sub-agents, or one background agent run. Hobby is free for 1,000 events a month with 14 days of retention. Pro is $299 a month plus $0.003 per event up to 1M, then $0.002, with unlimited retention and a 14-day free trial. Enterprise is custom.
- Choose it over Braintrust if
- you want production monitoring and Slack alerts on agents more than an eval workflow, and a $299 base plus usage fits.
5. Arize Phoenix
Phoenix is Arize's open-source tool for tracing, evals, datasets, experiments, and prompts, built on OpenTelemetry. For an eval-first team, it covers the same loop on servers you run, for free, and its evals run as pytest, Vitest, or Jest tests that gate CI. Arize AX, the hosted platform, adds online evals, alerts, and Signal, which scans traces every 6 hours by default and groups recurring failures into ranked issues. Dynatrace completed its purchase of Arize on October 1, 2026.
Where it is strong
- Evals written as pytest, Vitest, or Jest tests record every run to Phoenix and gate CI.
- Phoenix self-hosts for free with no license fees, usage limits, or feature gates, where Braintrust self-hosts only on Enterprise and keeps the control plane.
- AX Pro is $50 a month, far below Braintrust Pro at $249.
- Each Signal issue comes with a proposed prompt, code, config, or eval change.
Where it falls short
- Phoenix's docs send you to Arize AX for online evals on live traffic and for alerting, and Signal is part of AX.
- Elastic License 2.0, which bars offering Phoenix to others as a hosted service.
- Signal stops at 10 issues a month on AX Free and 25 on Pro. Repo access and fix pull requests need Enterprise.
- Arize now belongs to Dynatrace, which plans to fold it into its own platform over time.
- Pricing
- Phoenix is free to run on your own servers. Arize AX Free includes 25k spans and 1 GB a month and keeps data 15 days. AX Pro costs $50 a month for 50k spans and 10 GB, then $0.0008 per span and $3 per GB, and keeps data 30 days. Enterprise is custom and adds self-hosted AX.
- Choose it over Braintrust if
- you want evals that gate CI on open source you run yourself, with a $50 hosted plan when you need it.
6. Opik
Opik is Comet's Apache 2.0 platform for tracing, evals with 30+ built-in metrics, prompts, alerts, and production monitoring. Self-hosting is free, and Opik Cloud Pro is $19 a month. Like Braintrust's Topics, its failure scans run on credits. Diagnostics, run by the Ollie assistant, scans traces on request, or daily once you turn that on, groups repeated failures into one issue each, and suggests a root cause and a fix.
Where it is strong
- Pro is $19 a month, against $249 for Braintrust Pro.
- Free Cloud keeps 60 days of data, where Braintrust Starter keeps logs 14 days.
- Apache 2.0, with the open-source and hosted versions on one codebase.
- Online evaluation and 30+ built-in evaluation metrics in the open-source build.
Where it falls short
- Diagnostics runs on Ollie credits, and Comet does not publish what credits cost.
- Daily scans need someone to switch them on per project, and a day missed while they were off is never scanned.
- SSO and RBAC are Enterprise only, and self-hosted Opik has no user management.
- Self-hosting means running ClickHouse, MySQL, Redis, and object storage.
- Pricing
- Opik is free to self-host. Free Cloud: 25k spans a month, 60 days of retention. Pro: $19 a month for 100k spans, then $5 per 100k. Enterprise: custom. Ollie credits for Diagnostics are extra.
- Choose it over Braintrust if
- you want Apache 2.0 open source and a hosted plan at $19 a month, with longer history on the free tier.
Which tool is right for you?
- You want failures found and ranked by severity with nothing to turn on, from $79 a monththree.dev
- You want open-source evals and tracing on your own servers, or a $29 cloud planLangfuse
- Your app runs on LangChain or LangGraph and you want drafted fix pull requestsLangSmith
- Production alerts matter more to you than an eval workflowRaindrop
- You want evals that gate CI on open source you run yourselfArize Phoenix
- You want an Apache 2.0 tool and a cloud plan under $20 a monthOpik
Questions
What is the best Braintrust alternative?
Start from the reason you are leaving. For failures found with nothing to turn on and a paid plan below $249 a month, three.dev. For open source or a $29 cloud plan, Langfuse. For LangChain and LangGraph apps, LangSmith. For production alerts on agents, Raindrop. For evals you run on your own servers, Arize Phoenix or Opik.
Which Braintrust alternatives find production failures automatically?
three.dev needs no setup. It starts scoring a sample of your requests as they arrive, reports each defect as an issue, and groups issues into named failure modes, ranked by severity, once enough collect. There is no owner switch, facet, or credit balance to manage. Each other tool names its own condition in its docs, as of October 29, 2026. LangSmith Engine: a Plus or Enterprise plan, an organization admin and a per-project switch, a scan every 6 hours per its pricing page, and about 7 to 45 usage units of $1 per run, capped at 750 units a month by default. Raindrop Issue Detection: the Pro plan, $299 a month plus $0.003 per event. Arize AX Signal: a switch in each project, a scan every 6 hours by default, and a cap of 10 issues a month on Free and 25 on Pro; it is not part of Phoenix. Opik Diagnostics: the Ollie assistant, credits at a price Comet does not publish, and daily scans only after someone turns them on. Langfuse: Topics is "In progress" on its roadmap and, per its GitHub release notes, in a closed beta for allowlisted Langfuse Cloud projects in October 2026.
Is there a cheaper Braintrust alternative?
Braintrust goes from free Starter to Pro at $249 a month, with no plan between. three.dev Starter is $79 a month with scoring included, and Pro is $249. Langfuse Core is $29 a month, Arize AX Pro is $50, Opik Pro is $19, and LangSmith Plus is $39 per seat. Raindrop Pro costs more, at $299 a month plus usage. Each one meters usage differently (data, units, spans, traces, or events), so price your own traffic on each pricing page.
Which Braintrust alternatives are open source?
Langfuse's core is MIT licensed, Opik is Apache 2.0, and Arize Phoenix uses the Elastic License 2.0. All three are free to self-host. LangSmith is closed source and self-hosts on Enterprise. Raindrop is hosted, with self-hosting in beta. three.dev is hosted and is not open source. Braintrust publishes its SDKs and tools as open source; its platform is not published.
Braintrust vs Langfuse: which is better?
Langfuse's core is MIT licensed and free to self-host with no usage cap. Braintrust's platform is not published as open source, and it self-hosts only on Enterprise, with Braintrust running the control plane. Langfuse Cloud starts at $29 a month, where Braintrust goes from free to $249. Langfuse runs judges on your own LLM connection, and each score is a billable unit. Braintrust's Topics groups traces once an owner turns it on in a project, and Patterns is in public preview; Langfuse's Topics is in closed beta. Pick Langfuse for open source and a lower entry price. Pick Braintrust for Loop-drafted scorers and CI checks on every pull request.
Braintrust vs LangSmith: which is better?
LangSmith Plus costs $39 per seat, invited users included, so seven seats cost $273 a month before usage. Braintrust Pro is $249 a month with unlimited users, and three.dev has unlimited seats on every plan too. LangSmith's Engine drafts fix pull requests and fits LangChain and LangGraph apps closely. Braintrust's Topics and Patterns find problems once turned on in a project, and its GitHub Action runs evals on each pull request. Pick Braintrust for evals in CI. Pick LangSmith for LangChain depth and Engine.
Can I use three.dev and Braintrust together?
Yes. three.dev only changes the base URL your AI SDK calls. If you log to Braintrust with its SDK or OpenTelemetry, that can stay in place, so you can keep Braintrust for evals and CI and add three.dev to find and rank your production failures.
How do I move from Braintrust to three.dev?
Point your AI SDK at gate.three.dev, add a three.dev API key, and add the X-Three-Use-Case header. Or paste this prompt into your coding agent: "Install github.com/round3ai/skills and run its three-dev-setup skill in this repository." Scoring then starts on your live traffic, with no scorer or facet to set up.
Does three.dev sit in my request path?
Yes. Your requests pass through the proxy at gate.three.dev. Scoring happens after each response returns, so it adds no latency and never changes a request.
How we made this list
We make three.dev, so we list it first. For Braintrust, we read its pricing page, plans and limits, the Topics, Patterns, Loop, and self-hosting docs, and its changelog on October 29, 2026. Each other review comes from that tool's own site, docs, and pricing page, read the same day, and is written for a team leaving Braintrust. Every review says where its tool beats three.dev. Prices move, so confirm them on each pricing page.
Sources
- three.dev docs: sending requests
- three.dev docs: live scoring
- three.dev docs: failure modes
- Braintrust pricing
- Braintrust plans and limits
- Braintrust Topics
- Braintrust: enable Topics
- Braintrust Patterns
- Braintrust deployment options
- Braintrust self-hosting
- Braintrust: review patterns
- Braintrust Loop and GitHub
- Braintrust: run evals in CI
- Langfuse pricing
- Langfuse self-hosted pricing
- Langfuse roadmap
- Langfuse: Topics in closed beta (GitHub)
- Langfuse: online evaluation
- Langfuse: LLM-as-a-judge
- Langfuse billable units
- Langfuse Halo
- Langfuse alerts
- Langfuse joins ClickHouse
- LangSmith pricing
- LangSmith Engine
- LangSmith Engine setup
- LangSmith Insights
- LangSmith usage and billing
- LangSmith self-hosting
- LangSmith changelog
- Raindrop pricing
- Raindrop plans and limits
- Raindrop Issue Detection
- Raindrop signals
- Arize pricing
- Arize AX Signal
- Phoenix self-hosting
- Phoenix license
- Dynatrace completes Arize acquisition
- Opik pricing
- Opik Diagnostics
- Opik self-hosting
Ship on evidence, not vibes.
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