Decode & Verify Base64urlUInt-encoded RS256 Public Key from Google
Both values are unsigned, big endian values, encoded as base-64-url. Basically that means that there is no sign bit and that the most significant bit is all the way to the left (bit B_7 - zero based indexing - on byte index zero). So you first need to base-64-url decode the values and then convert them to a big number. Finally, you need to combine both big numbers to form the public key, by providing the numbers as modulus $n$ and exponent $e$.

If you cannot combine the numbers to a public key you may need to encode the public key as PKCS#1 public key or SubjectPublicKeyInfo, which is an X.509 structure. For both these operations you either need to create the encoding yourself (which is pretty hard) or you need to have access and understand how to use an ASN.1 library.



You may want to have a look at the RSA public key interface in the "hazmat" cryptography package, with load_rsa_public_numbers and public_bytes(encoding, format) with PEM and SubjectPublicKeyInfo.