ACL2 vs OpenJML

ACL2

6.6 #15 in Formal Verification Tools

About ACL2

OpenJML

5.9 #26 in Formal Verification Tools

About OpenJML
ACL2OpenJML
Free planNoYes
Free trialNoNo
Paid from—Free
Open sourceNoNo
PlatformsLinux, macOS, self-hosted, Windowsapi, extension, Linux, macOS, Windows
Free planYes—
Verification methoddeductivedeductive
Supported formalismstheorem-provingcontracts
CounterexamplesYesYes
Proof artifactsYes—
Input languagesACL2 logic and a subset of applicative Common LispJava and JML
Deploymentself-hostedself-hosted

Both are listed in Best Formal Verification Tools. On The Geeks Club, ACL2 scores higher on our published basis.