Mastodon Profile Bio Custom Fields: How to Add and Verify Them

Your Mastodon profile bio can include more than a short description. Custom fields let you add links to your website, GitHub, Patreon, or other personal pages directly on your profile. Without custom fields, visitors must search for your other accounts manually. This article explains how to add custom fields to your Mastodon profile bio and how to verify ownership of the linked pages.

What Are Mastodon Profile Custom Fields

Profile custom fields are key-value pairs that appear below your display name and bio on your Mastodon profile page. Each field has a label and a value. The label is a short text such as “Website” or “GitHub.” The value can be a link or plain text. When you add a URL as the value, Mastodon displays it as a clickable link.

You can add up to four custom fields. Many users include links to their personal blog, Patreon, Ko-fi, GitHub, LinkedIn, or a personal wiki. Custom fields help visitors find your other online presences without leaving Mastodon.

Verification is a two-way link check. When you add a link to your external site and that site links back to your Mastodon profile, Mastodon shows a green checkmark next to that field. This confirms you control the external page.

Steps to Add Custom Fields to Your Mastodon Profile

You must be logged into your Mastodon account. The settings page is identical on the web app and mobile web version. The mobile app may have a slightly different layout but the same options.

1. Open your preferences
   Click the gear icon or your profile avatar in the top navigation bar. Select Preferences from the dropdown menu.
2. Go to Appearance
   In the left sidebar, click Appearance. This section controls your profile layout and bio settings.
3. Scroll to Profile metadata
   Look for the Profile metadata section near the bottom of the page. You will see empty fields labeled Label and Value.
4. Add a label and value
   Type a short label in the Label field, for example Website. In the Value field, paste the full URL such as https://example.com. You can also enter plain text without a link.
5. Add more fields
   Click the Add another field button below the first row. Repeat step 4 for each additional field. You can add up to four fields.
6. Save your changes
   Click the Save changes button at the bottom of the page. Your new custom fields appear on your profile immediately.

How to Verify Custom Fields on Mastodon

Verification requires two steps. First, add the external link as a custom field value. Second, add a link back to your Mastodon profile on that external page. Mastodon checks for a rel=me attribute on the return link. When both links exist, Mastodon shows a green checkmark next to the custom field.

Step 1: Add the external link to your Mastodon profile

Follow the steps above to add a custom field. The value must be a full URL starting with https://. Do not use shortened URLs or redirects. Mastodon will not verify links that redirect.

Step 2: Add a rel=me link on your external site

Edit the HTML of your external page. Add this line inside the section:

<link rel="me" href="https://mastodon.instance/@yourusername">

Replace mastodon.instance with your Mastodon server domain and yourusername with your exact username. Save the file and publish the change.

Step 3: Wait for Mastodon to recheck the link

Mastodon rechecks verification links periodically. You can force a recheck by reloading your profile page or logging out and back in. The green checkmark appears within a few minutes if both links are correct.

Common Issues and Things to Avoid When Using Custom Fields

The green checkmark does not appear after adding both links

Mastodon requires the return link to have the rel=me attribute. A standard hyperlink without rel=me will not trigger verification. Check that the link tag contains rel=”me” exactly. Also ensure the URL in the Mastodon custom field matches the URL of the page containing the rel=me link. A mismatch in http vs https or trailing slashes breaks verification.

The custom field shows a broken link icon

A broken link icon appears when Mastodon cannot reach the external URL. This can happen if the site is down, the URL is misspelled, or the site blocks Mastodon’s crawler. Verify the URL works in a browser. If the site uses a firewall or bot protection, you may need to whitelist Mastodon’s IP range.

Only four custom fields are allowed

Mastodon currently limits custom fields to four entries. You cannot increase this limit through settings. If you need more links, consider adding a single field with a link to a personal page that lists all your other profiles.

Verification fails for social media profiles like Twitter or Instagram

Some social media platforms do not allow you to add arbitrary HTML to your profile. Twitter, Instagram, and Facebook do not support rel=me links. Mastodon cannot verify these links. You can still add them as custom fields without a checkmark. For verified links, use a personal website, GitHub, or a blog where you control the HTML.

Custom Fields on Mastodon vs Other Platforms

Item	Mastodon	Twitter	LinkedIn
Maximum fields	4	1 link in bio	3 custom links in contact info
Verification method	rel=me link exchange	Blue checkmark paid subscription	No link verification
Clickable links	Yes, all fields	Only the bio link	Yes, all links
Plain text fields	Yes	No	No
Green checkmark	Yes, for verified links	No	No

Mastodon’s custom fields give you more control than Twitter or LinkedIn. You can mix text and links, and the verification system is open and free. No paid subscription is required for the green checkmark.

After setting up your custom fields, verify at least one link to a page you control. This builds trust with visitors and confirms your identity. You can also reorder fields by deleting and re-adding them in the desired order. Use the first field for your most important link such as your personal website or primary blog. The green checkmark will appear next to that field once verification completes.