A lightweight APK signing tool that does not require Android Studio or JRE.
$ git clone https://github.com/akavel/apksigner
$ cd apksigner
$ go build
$ ./apksigner -i unsigned.apk -k key.pk8 -c cert.x509.pem -o signed.apk
Apache License, Version 2.0. Based on apksigner by Fredrik Fornwall, in turn based on zip-signer by Ken Ellinwood.