Opik

Opik is software for logging and evaluating the actions of applications and agents that use large language models. It captures and visualizes traces, supports annotations, and keeps audit logs, giving teams tools to investigate behavior during development, testing, and production. Evaluation includes more than 30 metrics covering outcomes such as relevance, context precision, task completion, and hallucination. For production monitoring, Opik can assess traces in real time, alert on failed criteria, and track token use and model costs. Test Suites provide pass/fail assertions; an Agent Playground supports end-to-end tests; and a Prompt Optimizer offers six algorithms. The core observability and evaluation features are open source and can run locally. Opik provides a REST API and Python client, Python and TypeScript SDKs, and integrations with more than 40 frameworks, model providers, and gateways, including LangChain, OpenAI, Google ADK, and LangGraph. Free Cloud allows up to 10 team members, 25,000 monthly spans, and 60-day retention. Pro Cloud is $19 per month.

Opik brings tracing, evaluation, testing, and production monitoring into one toolkit for LLM applications and agents. Teams can start with a free plan or run the open-source core locally; larger Cloud usage has paid limits and plans.

Opik suits teams developing applications or agents that call an LLM and need to inspect, evaluate, and monitor their behavior. Its free plans are suited to development and testing.

Opik is an observability and evaluation platform for software and agents that call large language models. It is best suited to teams that need to follow and assess LLM behavior from development through production. Its combination of tracing, testing, and monitoring is a strong case for it, though Cloud quotas may constrain heavier use.

Overview

Opik brings agent actions, evaluation workflows, and production checks into a single platform. Teams can use the hosted Cloud plans or run the open-source core locally. That choice is useful for organizations that want to keep deployment flexible, but the hosted tiers have clear monthly span limits that matter as workloads grow.

Key features

Tracing captures and visualizes agent actions, with annotation and audit logs to support investigation and review. The evaluation toolkit includes more than 30 metrics covering answer relevance, context precision, task completion, hallucination, and other outcomes. This gives teams a broad starting point for judging output quality; useful results still depend on choosing criteria that suit the application.

For production monitoring, Opik can evaluate traces in real time, alert when criteria fail, and track token usage and model costs. Test Suites use pass/fail assertions, the Agent Playground supports end-to-end tests, and the Prompt Optimizer includes six algorithms. Together, these features connect pre-release testing with ongoing monitoring rather than leaving teams to assemble separate evaluation stages.

The open-source core provides the observability and evaluation feature set for local use. Opik also includes a REST API and Python client, with Python and TypeScript SDKs listed, and integrations with more than 40 AI frameworks, model providers, and gateways. Named examples include LangChain, OpenAI, Google ADK, and LangGraph. This breadth should suit teams working across common LLM tooling, although the facts do not establish compatibility with every stack.

Pricing

Free Cloud costs $0 and allows up to 10 team members, 25,000 spans per month, and 60-day data retention. It is a practical starting point for development and testing, but the span ceiling may be limiting for teams sending production traffic through the hosted service.

Open Source costs $0 and offers the full AI observability and agent-testing feature set using the same codebase as the hosted versions, deployed on infrastructure the team runs. It avoids a Cloud span quota, but self-hosting means taking responsibility for operating the deployment.

Pro Cloud is $19 per month, billed monthly. It raises the allowance to 50 team members and 100,000 spans per month, retains data for 60 days, and allows customizable span limits and retention periods. Email support is included, alongside community and self-service support. This is the more suitable Cloud tier for a growing team, though workloads beyond its allowance may require custom limits.

Enterprise has custom pricing, unlimited team members, custom usage plans, flexible deployments, dedicated support, and SLAs. It is aimed at organizations that need tailored usage or deployment arrangements. Enterprise security includes SSO and compliance coverage for SOC 2, ISO 27001, ISO 9001, HIPAA, and GDPR. Comet also lists ISO 9001:2015, ISO/IEC 27001:2022, and SOC 2 Type 2 compliance.

Platforms

Opik is available through an API, on Linux, as a web service, and in a self-hosted deployment. The Cloud plans suit teams preferring a managed option; the open-source version gives teams a local deployment path.

Who it's for

Opik fits teams building applications or agents that make LLM calls and need to trace behavior, evaluate outputs, test prompts and agents, and monitor production activity. Its free tiers are appropriate for development and testing. Teams with larger hosted workloads should compare expected monthly spans with the Cloud caps, while teams prioritizing control over deployment can choose the open-source core.

Pros and cons

• Pros: Tracing, evaluation, testing, and production monitoring sit in one toolkit, reducing the need to split those workflows across separate products.
• Pros: The open-source core can be run locally at no charge, with the same codebase as hosted versions.
• Pros: Free Cloud allows 10 team members and 25,000 monthly spans, making it usable for small development and testing teams.
• Cons: Free Cloud caps usage at 25,000 spans per month, and Pro Cloud at 100,000 spans per month unless limits are customized.
• Cons: The free Cloud and Pro tiers retain data for 60 days, which may not suit teams needing longer standard retention.
• Cons: Running the open-source edition locally avoids Cloud limits but requires a self-hosted deployment.

Alternatives

Langfuse is worth considering for teams whose needs fit its Hobby allowance of 50,000 units per month, 30 days of data access, and two users, or its $29 monthly Core plan.

Arize AX may suit teams wanting a free SaaS tier with unlimited users and evaluations, provided 25,000 monthly trace spans, 1 GB ingestion, 15-day retention, and 10 issues per month are enough.

SigNoz is another freemium option, including a community self-hosted plan.

W&B Weave is an alternative with a free plan for evaluations, tracing, and scorers, capped at 1 GB monthly ingestion and 5 GB storage.

Laminar may fit a small project that can work within its free plan's 1 GB of data, seven-day retention, one project, and one seat.

OpenLIT is an alternative for teams seeking unlimited self-hosted usage, users, projects, and environments on its OSS plan.

Traceloop is another freemium option built around the open-source OpenLLMetry observability project.

Helicone is an alternative that describes itself as open source and invites community contributions.

For broader comparisons, see AI Agent Observability Tools, LLM Observability Tools, AI LLM Evaluation Tools, AI LLM Observability Tools, Model Monitoring Software, and Machine Learning Model Monitoring Software.

Verdict

Opik is a strong choice for teams that want a single toolkit for LLM tracing, evaluation, agent testing, and production monitoring, with the option to run its open-source core locally. The main reason to look elsewhere is Cloud capacity: its published span allowances may not fit larger workloads, while Enterprise requires custom pricing.