Overview

Opik connects observability with evaluation and testing rather than treating production monitoring as a separate task. Teams can inspect agent actions, evaluate outcomes, test prompts and agents, then monitor production traces for failures and costs. The breadth is useful for teams building LLM applications, but it also means cloud plan limits deserve attention as usage grows.

Key features

Tracing captures and visualizes agent actions, with annotation and audit logs for investigation and review. Evaluation includes more than 30 metrics spanning answer relevance, context precision, task completion, hallucination, and other outcomes. That gives teams a broad set of measures to work with, though they still need to choose criteria that reflect their application.

Production monitoring can evaluate traces in real time, alert when criteria fail, and track token usage and model costs. For development, Test Suites provide pass/fail assertions, the Agent Playground supports end-to-end tests, and the Prompt Optimizer includes six algorithms. This links pre-release checks to ongoing monitoring, a useful fit for teams that want evaluation to continue after deployment.

The core observability and evaluation feature set is open source and can be run locally. Opik includes a REST API and Python client; its pricing page also lists Python and TypeScript SDKs. More than 40 integrations cover AI frameworks, model providers, and gateways, with LangChain, OpenAI, Google ADK, and LangGraph among the named examples.

Pricing

Opik uses a freemium model, with hosted plans and a free self-hosted option. Free Cloud costs 0.00 USD per free and is billed $0. It allows up to 10 team members, 25,000 spans per month, and 60-day data retention. Those caps make it a practical starting point for development and testing, but teams with heavier trace volume or longer retention needs will need another plan.

Open Source costs 0.00 USD per free and is billed $0. It provides the full AI observability and agent testing feature set, uses the same codebase as the hosted versions, and is self-hosted. It avoids the stated cloud span quota, but requires teams to run the software themselves.

Pro Cloud costs 19.00 USD per month, billed $19 per month. It raises the allowance to up to 50 team members and 100,000 spans per month, with 60-day retention and customizable span limits and retention periods. Pro is the natural step up for teams that have outgrown Free Cloud; the listed base allowance still makes it important to match plan limits to workload.

Enterprise has custom pricing. It includes unlimited team members, custom usage plans, flexible deployments, dedicated support, and SLAs. Enterprise also lists SSO and compliance with SOC 2, ISO 27001, ISO 9001, HIPAA, and GDPR, making it the tier aimed at organizations with those requirements. Community and self-service support are listed across plans, while Pro and Enterprise add email support.

Platforms

Opik is available through an API and on the web, and supports Linux and self-hosted deployment. The choice of hosted cloud or self-hosting accommodates teams with different deployment preferences.

Who it's for

Opik is aimed at teams building applications or agents that make calls to an LLM. Its free plans suit development and testing, while the hosted plans offer a managed option with defined team, span, and retention limits. The local open-source version is a stronger fit for teams prepared to self-host and wanting the full observability and agent testing feature set.

Pros and cons

Pros: Tracing, evaluation, testing, and production monitoring sit in one workflow, including real-time criteria alerts and token-cost tracking.
Pros: The open-source edition provides the full stated feature set for self-hosting at 0.00 USD per free.
Pros: More than 30 metrics and over 40 integrations give teams a broad starting point for evaluation and connecting existing AI tools.
Cons: Free Cloud is capped at 25,000 spans per month and 60-day retention, which may constrain teams with higher-volume or longer-term needs.
Cons: Pro Cloud's $19-per-month plan still has a 100,000-span monthly allowance; higher usage or customized retention may require changes to the plan.
Cons: Self-hosting keeps the open-source option free, but makes operating the software the team's responsibility.

Alternatives

W&B Weave is worth considering for teams that want a hosted free tier with AI application evaluations, tracing, and scorers; its free plan specifies 1 GB/mo of data ingestion and 5 GB/mo of storage.

OpenLIT is an alternative for readers seeking a free option whose OSS plan specifies unlimited self-hosted usage, users, projects, and environments.

Helicone is another freemium, open-source alternative.

Maxim AI may suit a small team looking for a free developer plan, which allows up to 3 seats, 10k logs per month, and 3-day data retention.

Respan (formerly Keywords AI) offers a free plan with 100k logs and 1k scores, among other allowances, for teams comparing usage quotas.

Agenta is an alternative with a free Hobby plan capped at 2 team members, 5,000 agent runs per month, 20 evaluations per month, and one-week trace retention.

LangWatch is an open-source alternative under Apache 2.0; its Developer plan lists 50k events per month and 14-day data access.

Portkey is another freemium option, with a Developer plan that lists 10k recorded logs per month and three days of log retention.

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

Verdict

Opik is a strong choice for teams that need an end-to-end workflow for LLM agent tracing, evaluation, testing, and production monitoring, especially if self-hosting matters. Its open-source edition gives teams the full feature set without a plan fee, while hosted users get a clear route from a free tier to Pro and custom Enterprise usage. Look elsewhere if your cloud workload does not fit the span ceilings or if self-hosting is not appealing and the hosted allowances are too restrictive.

	Opik	Tangle
Free plan	Yes	Yes
Free trial	Yes	No
Paid from	$19/mo	Free
Open source	No	No
Platforms	api, Linux, self-hosted, Web	api, Linux, Web
Free plan	Yes	Yes
Paid from	19 /mo	29 /mo
Tool-call checks	—	Yes
Trace ingestion	—	Yes
Regression runs	—	Yes

Opik vs Tangle

Opik

Tangle