We are happy to announce, that development of KeY is finally public! Our new home is https://github.com/keyproject/ on Github with many repositories, for example,

Functional Verification
Tired of experiencing bugs that weren't covered by your test cases before? KeY lets you augment your Java program with a specification written in the Java Modeling Language JML and helps you proving that your program behaves as it should.

Symbolic Debugging
Debugging sucks! Well, not if you're using our Symbolic Execution Debugger. Profit from a graphical visualization of the program's execution flow, state inspection and various other features to quickly uncover undesired behavior!

Teaching and Research
KeY is already used extensively for teaching at different universities. Use the tool's possibilities for teaching your students important concepts like design by contract, applied logics and program verification. Or use KeY for realizing your research project.
Most Recent Posts
The new book has arrived!
Just in time for the holiday season, the new book has arrived.
The LNCS volume 12345* “Deductive Software Verification: Future Perspectives” contains a collection of articles – reflections on the occasion of 20 years of KeY.
KeY 2.10
Just in time to put it under your christmas tree, we are happy to present the new 2.10 version of KeY.
Proving Line Wrapping in KeY, Why3, Dafny and Frama-C
This is a short comparison report about a verification task solved with KeY, Why3, Dafny and Frama-C.
The original challenge comes from a real-world situation. There is no particular “trick” needed for the specification and verification; it is rather straightforward. Yet, the required annotations to achieve the specification are not too few – making the example a good opportunity to compare different specification languages. Continue reading “Proving Line Wrapping in KeY, Why3, Dafny and Frama-C”
KeY Tutorial at VerifyThis 2021
During the VerifyThis competition 2021, KeY was invited to present itself as a Java verification tool.
It is customary for Verify This that for one tool after a brief introduction into the concepts of the tool, the participants are invited to solve a micro challenge – with a little help from present KeY developers.
Functional Verification
We can do better than testing!
KeY lets you specify the desired behavior of your program in the well-known specification language JML, and helps you proving that your programs conforms to its specification. That way, you did not only show that your program behaves as expected for some set of test values - you proved that it works correctly for all possible values! Go beyond testing - start proving!

Symbolic Debugging The next-generation debugger.
Imagine that you start debugging without having to think of particular input values. Your debugger instantly tells you that part of your code is unreachable, shows you all feasible runs in a beautiful graph and gives you graphical hints on where the problem you're after could possibly hide. While performing all this magic, it gracefully integrates within the Eclipse IDE and offers tools (breakpoints etc.) that you know from the debuggers of yesterday. Meet the Symbolic Execution Debugger!

Teaching & Research It was never easier to fall in love with formal methods.
Use our tool to demonstrate to your students that formal concepts, like first-order logic, Hoare logic and symbolic execution, are not just dry theoretical ideas, but are practically used and even integrated into the IDE they know. KeY is already extensively used in different universities, in several countries.
Currently, our team is spending a lot of effort on making KeY even more attractive to new research projects by increasing its extensibility. Use KeY for your own research project or in your courses!
