Comet Opik review

Comet Opik is the best-value pick on this list. The pricing page says the open-source edition shares the same codebase as the hosted versions and includes agent tracing, test suites and the agent playground. Free Cloud covers up to 10 team members, 25k spans a month and 60-day retention, which is longer than the free tiers from Langfuse, Arize or Braintrust. Pro Cloud costs $19 a month for up to 50 team members and 100k spans, with customizable span limits and retention. The feature list includes execution graphs, sessions, cost tracking, test suites with assertions, 30+ built-in metrics, annotation queues and integrations with 40+ frameworks, providers and gateways. It scores lower on features than the top three because production alerting and analytics are less extensive in its published plan comparison, and the Ollie coding assistant requires buying tokens after the trial.

Who it is for

small teams that want an open-source tool with a low cloud price

Price

Open source and Free Cloud at $0; Pro Cloud $19 a month for up to 50 team members.

Expanded usage for teams $19 Per month
Quoted from the vendor pricing page on November 12, 2026.

Key features

• Agent tracing with execution graphs, sessions, and token and cost tracking
• Test suites with item-level and suite-level assertions
• 30+ built-in evaluation metrics plus custom metrics
• Annotation queues for traces or whole conversations
• Integrations with 40+ AI frameworks, model providers and gateways, plus OpenTelemetry

Strengths and weaknesses

• Strength: Free Cloud covers up to 10 team members and 25k spans with 60-day retention
• Strength: Pro Cloud at $19 a month is the lowest paid price on this list
• Strength: The open-source edition uses the same codebase as the hosted versions
• Weakness: Pro Cloud includes 100k spans a month, so busy apps need custom limits
• Weakness: The Ollie assistant needs purchased tokens after a free trial
• Weakness: SSO and compliance packages are Enterprise only

Key facts

• Free Cloud: Up to 10 members, 25k spans a month, 60-day retention
• Pro Cloud: $19 a month, up to 50 members, 100k spans
• Open source: Same codebase as hosted versions
• Integrations: 40+ frameworks, providers and gateways

Where it ranks

Comet Opik is No. 5 in our Best LLM Observability Tools verdict.