Why signatures matter
APK signatures prove that a package has not been tampered with between build and distribution. Even if you distribute internally, signatures allow your team to track whether the right keystore was used and whether a build is consistent with previous releases.
Where signatures live
Most APK signing evidence is stored under the META-INF directory inside the APK ZIP archive. Common files include .RSA, .DSA, .EC, .SF, and MANIFEST.MF. These do not replace deeper cryptographic validation, but they are reliable static indicators that a signature exists.
Practical checks before release
A release manager should confirm that the META-INF folder exists, signature files are present, and the signature hashes match expectations across builds. This is especially important if a build is distributed outside the Play Store or via enterprise channels.
What static checks do and do not prove
Static checks cannot guarantee that an APK is safe, but they can prove that a known signing key was used. Combine signature checks with manifest inspection, permission review, and targeted device testing for full confidence.
How openapk.site helps
The Signature Checker on openapk.site highlights signature artifacts and exposes quick hashes. It is a fast step in a release checklist that is easy to share with QA and support teams.