base64 URL encoding vs URL encoding

main.py

import json
import random

style = ["Structured", "Plain"]

max_size = 320
dic = {i: style[random.randint(0, 1)] for i in range(max_size)}
json_dic = json.dumps(dic,ensure_ascii=False)
print(json_dic)

main.sh

#!/bin/bash

python main.py | jq -c -r > main.json

cat main.json | base64 -w 0 | tr '/+' '_-' | tr -d '=' > base64url.txt
cat main.json | nkf -WwMQ | sed 's/=$//g' | tr = % | tr -d '\n' > url_encode.txt

wc -m *.txt

$ ./main.sh
 6870 base64url.txt
 8993 url_encode.txt