The best LLMOps and AI evaluation platforms in 2026

The best LLMOps and AI evaluation platforms right now are Braintrust, LangSmith and Arize AX, out of 6 we have reviewed. Each is ranked by our rating, with its price, our verdict and who it suits.

By Andrew Miller · Updated Nov 2, 2026 · How we review

How we ranked: by our rating out of 5, from reviews built on each product's own pricing, documentation and policies plus independent benchmarks where they exist, each checked on the date shown in the review. We take no affiliate commission.

1. 1
   

   Braintrust

   Braintrust is for teams whose hardest question is whether the last change made the product better, and it bills by data rather than by person, which suits big teams and stings agents that log a lot.

   Best for: Product teams who want evaluation-driven development with hosted tracing and are happy to pay for a managed service.

   Price: Starter free (1 GB data, 10k scores, $10 model credits, 14-day retention, unlimited users; then $4/GB and $2.50 per 1,000 scores). Pro $249/month (5 GB, 50k scores, $100 model credits, 30-day retention; then $3/GB and $1.50 per 1,000 scores). Enterprise custom, with SAML, BAA and self-hosted data plane. Qualifying startups get Pro free for 6 to 12 months.

   Read our Braintrust review
   4.3/5
2. 2
   

   LangSmith

   LangSmith has the deepest, most mature tracing and evaluation for LangGraph agents, sold per seat at a price that rewards small teams with big budgets.

   Best for: Teams building production agents on LangChain or LangGraph who want hosted tracing, evaluation and deployment from one vendor.

   Price: Developer free (1 seat, 5,000 base traces/month). Plus $39/seat/month (10,000 base traces, then pay-as-you-go; one small serverless deployment). Enterprise custom, with hybrid or self-hosted options. Base traces kept 14 days, extended traces 180 days.

   Read our LangSmith review
   4.2/5
3. 3
   

   Arize AX

   Arize AX gives you serious agent tracing and evals on open instrumentation, but its cheap plans run out fast and its roadmap now belongs to Dynatrace.

   Best for: Engineering teams running production agents who want hosted tracing and evals on open, portable instrumentation and can negotiate an Enterprise contract.

   Price: AX Free $0 (25,000 spans, 1 GB a month, 15-day retention); AX Pro $50/month (50,000 spans, 10 GB, 30-day retention); Enterprise custom with SSO, HIPAA and self-hosting. Unlimited users on every plan.

   Read our Arize AX review
   4.1/5
4. 4
   D

   Datadog LLM Observability

   If your company already lives in Datadog, this is the sensible place to watch your agents, and its per-model-call billing is fairer than it first looks.

   Best for: Engineering teams already running Datadog who want agent traces next to their service and infrastructure monitoring.

   Price: Free up to 40K LLM spans/month with 15-day retention. Pro from $160/month annual, $200 month-to-month or $240 on demand, for 100K LLM spans; then $3.50 (annual), $4.20 (month-to-month) or $5 (on demand) per 10K LLM spans. Retention add-ons listed at $6.50, $8 and $9 per 10K spans a month for 30, 60 and 90 days. Only LLM spans are billed.

   Read our Datadog LLM Observability review
   4.0/5
5. 5
   

   Lakera Guard (Check Point AI Guardrails)

   Lakera Guard is a well-documented filter against prompt injection that takes one API call to add, but past 10,000 requests a month you are negotiating with Check Point's enterprise sales team.

   Best for: Teams that want a managed screen for prompt injection and data leaks in front of chatbots and agents, without operating their own classifiers.

   Price: Community free: 10,000 requests/month, 8k-token prompts, SaaS only. Enterprise by quote: flexible volume, SaaS or self-hosted, SSO, RBAC, SIEM integration. No published price beyond the free tier.

   Read our Lakera Guard (Check Point AI Guardrails) review
   4.0/5
6. 6
   S

   Splunk Agent Observability

   Galileo's small judge models make it cheap to score every agent conversation, but under Splunk it has become an enterprise purchase with a sales call in front of it.

   Best for: Large organisations already on Splunk Observability that want to score every agent conversation and block unsafe actions at runtime.

   Price: Agent Observability from $100/month per 1.2M spans a year, billed annually, including 500M Luna tokens and 5 Luna fine-tuning runs a year; extra Luna tokens and longer retention by quote. Splunk Observability Cloud Free Edition (up to 15 hosts, no expiry) includes agent tracing. Galileo's old Free (5,000 traces/month) and Pro ($100/month billed yearly, 50,000 traces) plans are no longer published.

   Read our Splunk Agent Observability review
   3.7/5