Inspect AI vs Confident AI (DeepEval)
Both are eval frameworks tools. Here is how they actually differ on price, billing model and deployment.
Inspect AI
The UK AI Security Institute's MIT-licensed eval framework, built for reproducibility rather than dashboards. Adopted by Anthropic, DeepMind and xAI - it is the closest thing this category has to a research-grade standard.
Confident AI (DeepEval)
The pytest for LLM apps - write test cases, run "deepeval test run" in CI. The OSS framework is Apache-2.0 and free; the Confident AI cloud has a steep pricing cliff from $200/mo to $2,000/mo.
| Inspect AI | Confident AI (DeepEval) | |
|---|---|---|
| Category | Eval Frameworks | Eval Frameworks |
| Our rating | 5/5 | 4/5 |
| Starting price | $0 (open source) | $200/mo |
| Billing meter | No usage metering | No usage metering |
| Free plan | Yes | Yes |
| Free self-hosting | Yes, free | Yes, free |
| Best for | Teams doing serious, reproducible model evaluation - safety testing, capability benchmarking, agent evaluation, or anything where the result has to withstand scrutiny. Also the right choice for anyone publishing evaluation results. | Python teams who want pytest-style LLM evals in CI/CD and can either live in the OSS framework or absorb the cloud's pricing steps |
Our verdict on Inspect AI
Inspect AI is the most rigorous evaluation framework in this category and it is not particularly close. Built by the UK AI Security Institute, an organisation that runs thousands of evaluations on frontier models, its design goal was reproducibility - and it shows in choices nothing else makes, like shipping statistical bootstrap and confidence intervals rather than bare point scores, and logging complete transcripts of every sample. Sandboxed execution with Docker built in means you can safely evaluate models that write and run code. Agent and multi-turn workflows are first-class rather than retrofitted. It has been adopted by Anthropic, DeepMind and xAI, which is about as strong a signal as exists, since those are the organisations running the largest evaluation workloads anywhere. The trade-off is that it is a research instrument, not a product tool. It is Python-only, code-first, has no hosted service or dashboards, and does not do production observability at all. If you want to know whether your RAG chatbot is any good this week, use Ragas. If you need a number somebody will challenge, use this.
Full Inspect AI review →Our verdict on Confident AI (DeepEval)
If your team writes Python and thinks in tests, DeepEval is the most natural eval framework there is - it really does feel like pytest for LLM apps, and the OSS core is free under Apache-2.0. The friction is the cloud. The Free tier is stingy at 5 test runs a week, and the jump from $200/mo Starter to $2,000/mo Team is a real 10x cliff. Watch the API bills too - almost every metric is LLM-as-judge.
Full Confident AI (DeepEval) review →Frequently Asked Questions
What is the main difference between Inspect AI and Confident AI (DeepEval)?
Inspect AI: Teams doing serious, reproducible model evaluation - safety testing, capability benchmarking, agent evaluation, or anything where the result has to withstand scrutiny. Also the right choice for anyone publishing evaluation results. Confident AI (DeepEval): Python teams who want pytest-style LLM evals in CI/CD and can either live in the OSS framework or absorb the cloud's pricing steps Both sit in Eval Frameworks, so the decision usually comes down to billing model and deployment rather than raw capability.
Which is cheaper, Inspect AI or Confident AI (DeepEval)?
It depends entirely on your workload shape, because they meter differently - Inspect AI bills on no usage metering and Confident AI (DeepEval) bills on no usage metering. Published starting prices are $0 (open source) and $200/mo respectively, but those numbers are not comparable until you apply them to the same traffic. Use our cost calculator to model both against your own request volume and span count.
Can I self-host Inspect AI or Confident AI (DeepEval)?
Inspect AI: Yes, free. Confident AI (DeepEval): Yes, free. Free self-hosting means no licence fee, not no cost - you still own the infrastructure, upgrades and on-call.