Is this the same as keytool -genkey?

Yes — it produces the same artifacts as 'keytool -genkeypair -keyalg RSA -keysize 2048 -validity 10000': an RSA key pair, a self-signed X.509 certificate and a password-protected keystore, in both JKS and PKCS#12 formats. The tool even shows you the equivalent keytool command.

Can I use this for an Android app signing key?

Yes. Generate an RSA keystore (JKS or PKCS#12) with a long validity and back it up carefully — if you lose an Android release signing key you can never update that app again. Because generation is 100% local, the key never leaves your device.

What's the difference between JKS and PKCS#12?

JKS is Oracle's legacy Java-only format. PKCS#12 (.p12/.pfx) is the modern, cross-platform standard that keytool now defaults to and that OpenSSL, Windows and macOS all read. KeyForge can output both.

Which key size and validity should I choose?

RSA 2048 is the standard minimum; 3072 or 4096 for higher security. For release signing keys use a very long validity (e.g. 10000 days / ~27 years) so the key outlives the app.

Keystore Generator — JKS & PKCS#12 (keytool online)

Generate an RSA key, self-signed X.509 certificate and a password-protected JKS + PKCS#12 keystore in your browser — the exact output of keytool -genkey, for Android/Java release signing and more.