From $84 per user/month · Free plan🇺🇸
Test automation for web, mobile, API and desktop with AI test case generation from requirements, self-healing and an MCP connection.
Diffblue Cover AI features and pricing (October 2026)
Writes Java unit tests automatically using reinforcement learning, as an IntelliJ plugin, command-line tool and CI pipeline.
FreemiumFree plan
Pricing: Freemium
Community Edition is free for one user and 25 methods per month. Developer, Teams (from 10 licenses) and Enterprise (from 20 licenses) are paid; amounts could not be read during our check in September 2026.
What is Diffblue Cover?
Diffblue Cover writes unit tests for Java code automatically. It uses reinforcement learning to generate tests that compile and run, and is aimed at development teams with large Java codebases that want more test coverage with less manual work.
Cover consists of a plugin for IntelliJ, a CLI, Cover Pipeline for CI systems and Cover Reports for coverage analytics. Enterprise adds Cover Refactor and Cover Optimize. Kotlin projects can be covered through the CLI, which writes Java unit tests for them. Four editions exist: a free Community Edition limited to 25 methods a month, a Developer Edition, a Teams Edition with ten licenses and up to 250,000 lines of code, and Enterprise for larger codebases. Diffblue Limited is registered in England and Wales and based in London.
Diffblue Cover AI features and use cases
- Writes unit tests for existing codeCover analyzes Java methods and classes and writes unit tests that compile and pass against the current behavior. Teams raise coverage on legacy code without writing each test by hand.
- Keeps tests current in CICover Pipeline runs in the CI system and generates or updates tests when code changes. The test suite follows the codebase instead of falling behind after each release.
- Improves testabilityCover Refactor suggests changes that make code easier to test. Developers can unblock classes for which no tests could be generated.
- Runs only relevant testsCover Optimize selects the tests that matter for a given change. Pipelines finish faster because unaffected tests are skipped.
What sets Diffblue Cover apart
- Uses reinforcement learning rather than a large language model to generate tests.
- Focused on Java, with Kotlin projects supported through the CLI.
- A free Community Edition exists for single developers, limited to 25 methods a month.
Where Diffblue Cover is strongest
United Kingdom Available internationally
Diffblue Limited is registered in England and Wales and based in London.
Questions to ask before you buy Diffblue Cover
Check which edition fits your codebase: the CLI, Pipeline and Reports start with the Teams Edition, and Refactor and Optimize require Enterprise. Prices were not readable on the website in September 2026, so request a quote. The privacy notice covers licensing and telemetry data sent to Diffblue; confirm with the vendor how source code is handled in your setup.
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Questions about Diffblue Cover
Which languages does Diffblue Cover support?
Cover writes Java unit tests. Kotlin projects are supported through the CLI, which generates Java unit tests for them.
Is there a free version?
Yes. The Community Edition is free for a single user and limited to 25 methods per month in the IntelliJ plugin. A free trial of the plugin and CLI is also available.
Does Cover use a large language model?
According to the documentation, Cover is a reinforcement learning platform. The vendor presents this as its approach to generating tests.
Diffblue Cover update historyno updates yet
No changes recorded for Diffblue Cover yet.
Changes the vendor made and confirmed user reports, each checked against the vendor's own pages. We review every tool monthly.
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