Thousands of people use our Community Edition (CE) plugin for IntelliJ to write Java unit tests every week. At the time of writing, Community Edition users have written over 3.5 million free unit tests, saving them an estimated 393 years of time.

We make Diffblue Cover available free for limited personal use as a community service. To fund the company we sell a paid product for larger scale commercial use, which comes with the things most companies need: legal indemnification for generated code, full support and a more powerful feature set including CI/CD integrations. That said, we’ve seen a very small fraction of users seeking to work around the limits of Community Edition for large-scale commercial use, so we looked at how we can avoid that while continuing to be free for personal use.

Effective immediately, you’ll be able to write 100 unit tests for free each week using Community Edition. This replaces the previous daily limit, and will have no impact on >90% of CE users.

If you want to try Cover at a larger scale, and also get access to the command-line version, then you can sign up for the 14-day Teams Edition trial. During the trial you can write 1000 tests per week. If you feel you need to be able to do more during a trial, you can reply to the email we send you with the license key and our friendly support team will respond.

Our Community Forum is the place to ask questions, get help with using CE and tell us about any problems: The Diffblue team monitors the forum during UK working hours and is happy to respond.

If you’d like to inquire about paid options for Diffblue please contact us here:

To be clear, the weekly limits apply to a trailing 7-day window. So, if you wrote 25 free tests a day for the first 4 days, then on day 8 you’d be able to write another 25 free tests.