(very basic) script to convert a Keptab JSON export to one compatible with Onetab. Loosely based off of a scipt that does the opposite here -> https://gist.github.com/helpimnotdrowning/d14b3e97cb20bd6aaa6dc49583979b28

keptab_to_onetab.py

# very basic, doesnt account for locked, pinned stuff. you are free to figure it out yourself,
# but this is all I need, assuming anyone ever sees this lmao

import json
import random

DEBUG = False

def write_file(file: str, content: str) -> None:
    """Write content to file"""
    with open(file, 'w+') as file_:
        file_.write(str(content))

def dice() -> bool:
    if DEBUG:
        return random.randrange(0,500) == 47
    else:
        return False

with open('keptab.json') as f:
    keptab = json.load(f)

onetab = []
counter = 0

for group in keptab:
    for tab in group['tabs']:
        # sometimes the tab title will have an extra space at the start, this
        #     removes it. the problem comes from (i think) the OneTab -> Keptab
        #     converter on the Keptab site that doesn't strip the space after
        #     the line marker, ex. "http://a.co | Website" became " Website",
        #     not "Website" because it splits the string on the " |" part and
        #     forgetting the space afterwards (" | ")
        title = tab['title'].strip()

        onetab.append(abstring := f"{tab['url']} | {title}\n")

        if dice():
            print(f"URL : {tab['url']}")
            print(f"NAME: {title}")
            print(f"INDX: {counter}")
            print(f"FULL: {abstring}\n")

        counter += 1
    # the newline separates tab groups in OneTab
    onetab.append('\n')

write_file('onetab.txt', ''.join(onetab))
print("All tabs written to 'onetab.txt'.")