Mastodon is the largest federated social network in the world, composed of thousands of independent servers called instances that communicate through the ActivityPub protocol. Each instance has its own rules, moderation policies, and community culture, but users can follow and interact with anyone across the entire fediverse. This distributed model creates a rich, diverse social experience — but it also makes identity verification uniquely challenging. If you have connected with someone on Mastodon and want to confirm their identity, a reverse face search through facesearching can help you find someone by photo and verify that the person is real, regardless of which instance they are on.
The Identity Challenge of Federated Social Networks
On a centralized platform like Twitter/X, there is exactly one database of users, one set of rules, and one team that can verify identities. On Mastodon, every instance is its own independent server with its own user database. A scammer banned from one instance can simply create an account on another instance and continue operating. There is no central authority that can ban a bad actor from the entire network. This makes identity verification entirely the responsibility of individual users and instance moderators. A face search for online community moderators is becoming an essential tool for keeping federated communities safe.
How Face Search Handles Cross-Instance Verification
facesearching operates at the web level, not the platform level. When you upload a Mastodon user's avatar, the face search engine scans the entire public web for facial matches. It does not matter which Mastodon instance the person is on, or whether they have accounts on multiple instances. The search results show every public appearance of that face, including profiles on other social media platforms, blogs, news articles, and professional directories. This cross-platform, cross-instance capability is what makes reverse face search especially powerful for the federated social web. It is the same approach used for finding someone on Twitter/X by photo, but it works across the entire fediverse.
Step-by-Step: Verifying a Mastodon Profile
Step 1: Get the avatar from the Mastodon profile
Visit the Mastodon profile page and save the avatar image. Mastodon avatars are typically square and displayed at a consistent size across instances. If the avatar is not a face photo but rather an illustration, logo, or meme, ask the person to share a photo for verification.
Step 2: Upload to facesearching
Upload the avatar to facesearching. The engine will process the face and search across the indexed web. Results are returned in seconds, showing URLs where the face appears along with confidence scores.
Step 3: Check the instance itself
Each Mastodon instance has an about page that describes its community, rules, and moderation policies. Visit the instance's about page to assess whether it is a well-moderated community or a server with lax rules that might attract scammers. A legitimate user on a reputable instance is more likely to be genuine than an account on an instance known for harboring bad actors.
Step 4: Verify link verification
Mastodon supports link verification — users can add links to their profile that point to their own websites, and Mastodon highlights these links in green if the linked page links back to the Mastodon profile. This is a strong signal of identity ownership. Combine link verification with face search results for a comprehensive identity check. If the face appears on the linked website and the website links back to the Mastodon profile, you have strong evidence of authenticity.
The Role of Instance Moderators in Identity Verification
Mastodon instance moderators are the front line of defense against impersonation in the fediverse. They can ban users from their own instance and block entire other instances that harbor bad actors. However, moderators are volunteers who often lack the tools to verify identities at scale. facesearching provides a practical solution — moderators can run face searches on suspicious avatars and quickly determine whether a new user is using stolen photos. This is especially valuable for instances that serve vulnerable communities, such as LGBTQ+ spaces, activist networks, and survivor support groups.
The fediverse is built on trust between independent communities. Face search gives those communities the tools to verify who is joining them, without compromising the decentralized values that make Mastodon unique.