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Modify Increase post max characters count limit for self-hosted Mastodon server

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In the newest Mastodon V4.3.0, you only need to modify one file in order for the maximum character count to be changed.

If you search for the max_characters keyword in the Mastodon Github repository, you will see that it all points to the value within the StatusLengthValidator and a variable called MAX_CHARS

To modify it, first, ssh into your Mastodon server, and switch to the root shell:

sudo -s

Then, switch to the Mastodon user

su - mastodon

Now, modify the validator file:

nano -w live/app/validators/status_length_validator.rb

At the very top of the file, you will see the MAX_CHARS variable, which was by default 500, you can modify it to another integer, for example 3000 to allow a maximum of 3000 characters within each post.

# frozen_string_literal: true

class StatusLengthValidator < ActiveModel::Validator
  MAX_CHARS = 3000
  URL_PLACEHOLDER_CHARS = 23
  URL_PLACEHOLDER = 'x' * 23

That’s how you do it! Now, exit to root shell and restart the Mastodon processes, or simply reboot.

mastodon@Mastodon:~$ exit
logout
root@Mastodon:/home/ubuntu# systemctl restart mastodon*
root@Mastodon:/home/ubuntu#

Bonus: Reading maximum character count

You can read the custom character count from the /api/v1/instance endpoint, and find the character count in the Root/configuration/statuses/max_chatacters as an integer.

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