Evidently AI

Open-source Python framework for evaluating, testing and monitoring LLM apps and ML models.

Open sourceSelf-hostableLLM observability tools

Updated Nov 7, 2026 · AppBreakup editorial · Self-hosted, Web

Visit Evidently AI See 3 alternatives

Is Evidently AI free?

Yes, free and open source

License:: Apache 2.0

Checked on Evidently AI's site Nov 8, 2026

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All 3

Fiddler AI
Developer plan: $0.002 per trace
Datadog
Starting price: Infrastructure Pro, $15 per host/month billed annually
Weights & Biases
Starting price: From $60 a month (Pro), billed monthly

Verified facts: 4 of 4
Alternatives ranked: 3
Approved reviews: 0
Visits sent from here: 0

About Evidently AI

Evidently is an open-source framework for checking the quality of AI systems. It started as a tool for spotting data drift and falling accuracy in classic machine learning models, and has grown to cover LLM apps, RAG pipelines and agents too. You use it as a Python library: point it at a dataset of inputs and outputs and it runs checks for things like hallucinations, PII leaks, retrieval relevance, tone or drift, then produces visual reports or pass/fail tests you can run in CI. There are more than a hundred built-in metrics, and you can write your own using rules, classifiers or an LLM as judge. A self-hosted web platform adds projects, tracing, dashboards and monitoring over time. It suits data scientists and ML engineers who want evaluation in code and on their own infrastructure, rather than a hosted SaaS. The whole project is Apache 2.0 licensed and free to use; the company behind it also publishes free courses and guides.

Best for: ML and data teams who want code-first LLM evals and model drift monitoring on their own infrastructure.

What works

Apache 2.0 licensed, with no paid tier needed for the core features
Covers both classic ML drift monitoring and LLM and agent evaluation
Over 100 built-in metrics, plus custom checks and LLM-as-judge
Evaluations run as tests, so they slot into CI pipelines

Why people leave

Code-first Python library, so non-engineers will struggle to set up checks
You run and maintain the self-hosted platform yourself
Lighter on prompt management and production tracing than LLM-first tools

Evidently AI vs Fiddler AI, Datadog and Weights & Biases

From each app's listing and the prices verified on its own site. A dash means we haven't verified it yet.

Attribute	Evidently AI	Fiddler AI	Datadog	Weights & Biases
Pricing	Open source	Free plan + paid	Free plan + paid	Free plan + paid
Verified price	—	$0.002 per trace	Infrastructure Pro, $15 per host/month billed annually	From $60 a month (Pro), billed monthly
Free plan	Free app	Real-time guardrails	Yes, up to 5 hosts with 1-day metric retention	Yes, $0 a month
Open source	Yes	No	No	No
Self-hostable	Yes	No	No	No
Platforms	Self-hosted, Web	Web, Self-hosted	Web, iOS, Android	Web, iOS

Top Evidently AI alternatives

See all 3

1
Fiddler AI
Managed enterprise platform with guardrails and governance on top of ML and LLM monitoring, if you'd rather not self-host.
68.8
2
Datadog
Adds LLM observability next to your existing APM, logs and infrastructure monitoring in one tool.
64.7
3
Weights & Biases
Experiment tracking plus LLM tracing and evals in one hosted platform, if you already train models there.
52.6

Why people left Evidently AI

In reviewers' own words, from reviews of the apps they moved to. These are their opinions, not ours.

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Evidently AI: common questions

What is Evidently AI?

Evidently AI: Open-source Python framework for evaluating, testing and monitoring LLM apps and ML models. Best for ML and data teams who want code-first LLM evals and model drift monitoring on their own infrastructure. Available for Web, and you can host it yourself.

Is Evidently AI free?

Yes. Evidently AI is free, open-source software that you can host yourself.

Is Evidently AI open source?

Yes. The source code is on GitHub at evidentlyai/evidently. You can also run it on your own server.

What platforms does Evidently AI run on?

Evidently AI is available for Self-hosted and Web.

What are the best alternatives to Evidently AI?

The highest-ranked Evidently AI alternatives right now are Fiddler AI, Datadog and Weights & Biases. See the full ranked list for pricing, platforms and verified facts.

Evidently AI vs Fiddler AI: what's the difference?

Evidently AI is free and open source; Fiddler AI is free with paid plans. Evidently AI is open source and Fiddler AI is not. Both run on Web.

See all 3 Evidently AI alternatives

Evidently AI facts

4 of 4 verified

License: Apache 2.0; Checked Nov 8, 2026github.com(opens source in a new tab); “License: Apache-2.0 (Apache License 2.0).”
Built-in metrics: 100+; Checked Nov 8, 2026evidentlyai.com(opens source in a new tab); “Use the library of 100+ in-built metrics, or add custom ones.”
Self-hosting: Yes; Checked Nov 8, 2026docs.evidentlyai.com(opens source in a new tab); “You can use it as a standalone Python library or as part of a self-hosted platform.”
Covers: LLMs, RAG, agents and ML models; Checked Nov 8, 2026evidentlyai.com(opens source in a new tab); “monitor LLMs, RAG applications, AI agents, and ML models in a single framework.”