Overview

Opik is an observability and evaluation platform for applications and agents that call large language models. It suits teams that want to trace, test, and evaluate agent behavior across development and production, especially those that value a self-hosted option. Its broad workflow is a strong draw, but Cloud users need to plan around monthly span caps.

Key features

Opik records and visualizes agent actions, with trace annotation and audit logs for investigating behavior. More than 30 evaluation metrics cover outcomes such as answer relevance, context precision, task completion, and hallucination. That range can support varied evaluation needs, though teams must still choose criteria suited to their applications.

Production monitoring evaluates traces in real time, can alert on failed criteria, and tracks token usage and model costs. Test Suites add pass/fail assertions, the Agent Playground supports end-to-end tests, and the Prompt Optimizer offers six algorithms. Connecting these capabilities lets teams carry evaluation from testing into production rather than treating it as a pre-release task alone.

The core observability and evaluation feature set is open source and can run locally. Opik includes a REST API and Python client, and its pricing page lists Python and TypeScript SDKs alongside more than 40 integrations. Examples include LangChain, OpenAI, Google ADK, and LangGraph, giving teams several familiar routes into an existing 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 useful starting point for development and testing, but the span ceiling may constrain teams evaluating heavier workloads.

Open Source costs $0 and provides the full AI observability and agent testing feature set using the same codebase as hosted versions, for self-hosting. It avoids a Cloud span quota, but teams take on running it locally rather than using the hosted service.

Pro Cloud is $19 per month and includes up to 50 team members, 100,000 spans per month, and 60-day retention, with customizable span limits and retention periods. It adds room for larger teams and workloads than Free Cloud, while the monthly span allowance remains a planning consideration. Community and self-service support are listed across plans; Pro also includes email support.

Enterprise has custom pricing, unlimited team members, custom usage plans, flexible deployments, dedicated support, and SLAs. It is the fit for organizations that need those deployment and support terms. Enterprise security offerings include SSO and SOC 2, ISO 27001, ISO 9001, HIPAA, and GDPR compliance. Comet's Trust Center lists ISO 9001:2015, ISO/IEC 27001:2022, and SOC 2 Type 2 compliance.

Platforms

Opik is available through an API, on Linux, on the web, and as self-hosted software. The choice between hosted Cloud and local deployment is useful for teams with different operating preferences; the open-source option keeps the core feature set available to run locally.

Who it's for

Opik is aimed at teams building applications or agents that make calls to an LLM. Its tracing, tests, evaluation metrics, and production alerts suit teams that need to follow behavior throughout the development lifecycle. Free Cloud is suited to development and testing within its 25,000-span monthly cap; self-hosting is a natural choice for teams that want the full feature set locally. Teams that need more Cloud capacity can move to Pro, while enterprise deployment, support, and compliance requirements point toward custom-priced Enterprise.

Pros and cons

Pros: Tracing, evaluation, prompt and agent testing, and production monitoring share one platform, connecting pre-release checks with live monitoring.
Pros: The open-source version offers the full observability and agent testing feature set for local self-hosting at $0.
Pros: More than 30 metrics and over 40 integrations give teams a broad starting point for evaluation and connecting tools.
Cons: Free Cloud is capped at 25,000 spans per month and 60-day retention, which can limit room for growing workloads.
Cons: Pro Cloud raises the span ceiling to 100,000 per month but still has a published cap; higher or customized usage requires plan changes.
Cons: Enterprise uses custom pricing, so teams seeking a fixed published cost cannot compare it on price alone.

Alternatives

Langfuse is worth considering for a different free-tier balance: its Hobby plan allows 50,000 units per month and 30 days of data access for two users, while Opik Free Cloud allows 25,000 spans per month, 60-day retention, and up to 10 team members. LangWatch is another option if open-source software under Apache 2.0 is a priority. W&B Weave may suit teams looking for a free plan that specifies 1 GB monthly ingestion and 5 GB storage alongside evaluations, tracing, and scorers.

OpenLIT is a free alternative with an OSS plan advertising unlimited self-hosted usage, users, projects, and environments. Arize AX offers a free SaaS plan with 25,000 trace spans per month, 15-day retention, and unlimited users and evaluations. Laminar has a free plan with 1 GB data, seven-day retention, one project, and one seat. Traceloop is an alternative built around OpenLLMetry, an open-source observability project on OpenTelemetry. Helicone is another freemium option that describes itself as open source.

For broader discovery, browse AI Agent Observability Tools, AI LLM Observability Tools, AI LLM Evaluation Tools, Model Monitoring Software, LLM Observability Tools, or Machine Learning Model Monitoring Software.

Verdict

Choose Opik if your team needs one workflow for agent traces, evaluation, testing, and production monitoring, with the option to self-host the open-source core. Its strongest case is that breadth across the development lifecycle; look elsewhere if you need Cloud usage without span caps or a fixed Enterprise price.

	Alibi Detect	Opik
Free plan	No	Yes
Free trial	No	Yes
Paid from	—	$19/mo
Open source	No	No
Platforms	Linux	api, Linux, self-hosted, Web
Free plan	Yes	Yes
Drift monitoring	Yes	—
Deployment options	self-hosted	—
Paid from	—	19 /mo

Alibi Detect vs Opik

Alibi Detect

Opik