How to edit Telegram messages with monospace or HTML text using Telethon?

When utilizing Telethon to send Telegram messages with monospace or HTML text in Python, the parse_mode option (for example parse_mode='markdown' or parse_mode='html') works well during initial message sending. However, when attempting to edit a previously sent message, the parse_mode option does not appear to be available. How can I effectively edit a message and incorporate monospace or HTML-formatted text?

Example: Sending a message containing monospace string

sent_message = client.send_message(To_id, "the authentication code `8632496`", parse_mode='markdown')

Then editing the message and sending new text containing a monospace string

client(EditMessageRequest(
    peer=To_id,
    id=sent_message.id,
    message="the new authentication code `9832798237`"
))

the result:

I am aware that using entities is an option. For instance:

entities = [MessageEntityCode(offset=9, length=18)]  # specifying a code block entity
client(EditMessageRequest(
    peer=To_id,
    id=sent_message.id,
    message='This is a monospace string.',
    no_webpage=True,
    entities=entities
))

However, my text is long and contains multiple monospace strings originating from various sources, for example: text = f"something {variable1}, something {variable2}"

Hence, identifying the starting point and length of each monospace string is challenging.

I'd greatly appreciate any guidance on how to approach this issue, including methods or best practices for effectively managing monospace or HTML text when editing Telegram messages using Telethon.

client(EditMessageRequest( is a old, not preferred way of editing a message.

You should use client.edit_message method, in your example:

client.edit_message(tst_id, first.id, 'Oeps, the code is `1234789`')

This way, you don't even need to specify parse_mode it's the same as the message your editing.

Full code to test this:

from telethon import TelegramClient
import asyncio
import time

client = TelegramClient('anon', '1234567', '0123456789abcdef0123456789abcdef')
client.start()

async def main():
    tst_id = 1234

    first = await client.send_message(tst_id, "the authentication code `8632496`", parse_mode='markdown')

    time.sleep(3)

    second = await client.edit_message(tst_id, first.id, 'Oeps, the code is `1234789`')

loop = asyncio.get_event_loop()
loop.run_until_complete(main())

Result: message changes after 3 seconds: