Top 10 Braintrust Alternatives for Production Evals (2026)

Dylan Cable September 2, 2026

Braintrust meters tracing and scoring separately, so watching production and evaluating it both cost more as traffic grows. Here are 10 alternatives, compared on scoring live requests.

What Is Braintrust?

Braintrust is an evaluation platform for LLM applications, with observability attached. The core unit is an eval: a dataset, a task, and a set of scorers, run as an experiment so a prompt or model change produces a comparable number.

Braintrust Pricing

Braintrust publishes three tiers, and users, projects, playgrounds, experiments, and datasets are unlimited on all of them. What separates the plans is throughput and governance rather than seat count.

• Starter - Free. $10 in model credits then token rates, 1 GB of processed data then $4/GB, 10,000 scores then $2.50 per thousand, and 14-day retention.
• Pro - $249/month flat. $100 in credits, 5 GB then $3/GB, 50,000 scores then $1.50 per thousand, and 30-day retention extendable to 180 days at $0.50/GB/month.
• Enterprise - Custom. Adds custom retention policies, automated S3 export, SAML single sign-on, a business associate agreement, an uptime SLA, and on-premise or hosted deployment.

Why Look for a Braintrust Alternative?

The pricing structure above has consequences past the invoice, and a few of them decide whether the platform fits the job rather than what it costs. Here are some reasons people might look for a Braintrust alternative:

• Scoring live traffic bills separately from tracing it - Processed data and scores are two meters moving in the same direction.
• There is no tier between free and $249 - A team that outgrows 1 GB moves straight to Pro.
• Retention is short and capped - 14 days on Starter and 30 on Pro, extendable at $0.50 per gigabyte per month to a 180-day ceiling.
• Getting data out is an Enterprise feature.
• The packaging is evaluation-first - Tracing is built to feed the eval workflow.

10 Best Braintrust Alternatives for Production Evals

1. Respan

Respan runs the gateway, tracing, evaluations, and prompt management on one data plane, which means a score in production already carries the routing decision that served the request and the prompt version that produced it.

• Online evals: Judges, code checks, and human review run on sampled live spans.
• Meter: Logs and scores, counted separately from seats. Additional logs run $8 per 100,000 and additional scores $1 per 1,000.
• Pricing: Free covers the full platform at 100,000 logs, 1,000 scores, 5 datasets, 2 evaluators, and 5 prompts with unlimited seats.

2. Langfuse

Langfuse is an open-source LLM engineering platform.

• Online evals: Judges and code evaluators run on live observations.
• Meter: Units, where a trace, an observation, and a score each count as one.
• Pricing: Hobby is free with 50,000 units, 30-day access, and 2 users.

3. MLflow

MLflow is an Apache 2.0 project governed by the Linux Foundation.

• Online evals: Scorers run against traced production data.
• Meter: None. Cost is infrastructure and engineering time.
• Pricing: Free under Apache 2.0.

4. LangWatch

LangWatch is an Apache 2.0 platform for testing agents.

• Online evals: Monitors evaluate live traffic continuously.
• Meter: Events, where an evaluation step counts the same as an LLM call.
• Pricing: Developer is free with 50,000 events a month.

5. Confident AI

Confident AI is an evaluation-first platform.

• Online evals: Production traces are scored automatically.
• Meter: GB-months of trace spans, priced at $1 per GB-month.
• Pricing: Free covers 2 seats, 1 project, 1 GB-month.

6. Opik by Comet

Opik is Comet's Apache 2.0 platform.

• Online evals: Evaluation rules run on production traces.
• Meter: Spans. Additional spans are $5 per 100,000.
• Pricing: Free Cloud covers 10 team members, 25,000 spans a month.

7. Weights & Biases Weave

Weave is the LLM layer of Weights & Biases.

• Online evals: Monitors score live traces continuously.
• Meter: Ingested bytes.
• Pricing: Free is $0 with 1 GB a month of Weave ingestion.

8. LangSmith

LangSmith is LangChain's commercial platform.

• Online evals: Online and offline evaluators run.
• Meter: Seats plus traces.
• Pricing: Developer is free with one seat and 5,000 base traces a month.

9. Galileo

Galileo is an evaluation and guardrails platform.

• Online evals: Continuous scoring against live traffic.
• Meter: Traces.
• Pricing: Free covers 5,000 traces a month.

10. Arize Phoenix

Phoenix is Arize's open-source tracing and evaluation project.

• Online evals: LLM-as-a-judge and custom scoring run on spans.
• Meter: Spans and ingestion.
• Pricing: Phoenix self-hosts free with no usage caps.

FAQ

What is Braintrust used for?

Braintrust is used for evaluating LLM applications and observing them. Teams define an eval as a dataset, a task, and a set of scorers.

Braintrust vs LangSmith: which should you use?

Braintrust if evaluation results need to control what ships, and LangSmith if your application is built on LangChain or LangGraph.

How much does Braintrust cost?

Starter is free with 1 GB of processed data, 10,000 scores, $10 in model credits, and 14-day retention. Pro is a flat $249 per month for 5 GB, 50,000 scores, $100 in credits, and 30-day retention, with unlimited users on both.

Is Braintrust open source?

No. The platform, the control plane, and the Brainstore storage engine are closed source.