Quick verdict
Choose Mastodon if you want to choose a community operator, use ActivityPub and make server rules part of your decision. Choose Bluesky if custom feeds and a shared discovery experience are your starting point. First check where the people you want to speak with actually participate. A protocol preference cannot supply a missing community.
For an individual, try reading and replying for a week before moving your whole publishing routine. For a community, compare moderation responsibility and onboarding friction. For a publisher, test account identity, distribution and response handling as separate tasks. Nostr is a further option for people comfortable managing cryptographic keys and relay choices.
Comparison in the order you encounter it
| Decision | Mastodon | Bluesky |
|---|---|---|
| Signup | Choose an instance and its registration process | The Bluesky service provides a common starting point |
| Identity | Username at a server domain | Handle with an underlying decentralised identifier; domain handles are possible |
| Server choice | Operator rules and federation policy affect your account | AT Protocol separates data hosting from other network services |
| Discovery | Follow accounts, hashtags, lists and timelines | Follow accounts and choose custom feeds |
| Publishing | Check your server and client’s supported controls | Check the current app and posting limits |
| Moderation | Server decisions plus your own filters and blocks | Service moderation plus user-selected controls and label services |
| Portability | Migration has limits; post history does not move through account redirection | Protocol portability is distinct from a frictionless move in every app |
This is a documented comparison, checked on 1 November 2026, not a hands-on migration trial. Compare ActivityPub and AT Protocol for the technical architecture.
Discovery and the feed you want
On Mastodon, use descriptive hashtags and follow people rather than expecting one global view of the network. Your server only knows part of the federated conversation. Lists help separate close contacts, work and specialist interests. The client guide explains which controls have been documented in each app.
Bluesky’s custom-feed model lets feed generators choose which posts appear. A specialist feed can be useful without being your default timeline. Moderation and custom feeds are related choices, but subscribing to a feed does not hand it responsibility for all your safety settings.
Do not choose based on an undated largest-user-base claim. Registered accounts, active accounts and unique people measure different things. Check the statistics and definitions; the current snapshot is not a like-for-like Bluesky comparison.
Moderation and community responsibility
For a group joining Mastodon, read the instance rules together and decide who handles account access and incident reports. Choosing a server purely for its size leaves those decisions to chance. For Bluesky, review the default moderation settings and any extra label services before recommending a setup to other people. In either case, keep reporting routes accessible and agree who responds to replies.
What portability actually means
Mastodon’s account-move documentation explains aliases and follower migration. Posts are not transferred by that mechanism. Export important data before relying on a server move. Changing a client is a separate operation: it does not move your account to another network.
For Bluesky, separate your public handle, underlying identifier and hosting arrangement. Do not assume that a protocol’s migration design means every hosting provider or mobile interface provides a complete, convenient migration flow. Check current provider instructions before depending on it. Neither platform offers a universal move into the other with all replies, followers and history intact.
Publish to both when the audience justifies it
Using both can be sensible for a publisher whose readers are split across them. Adapt wording, mentions, alt text and links, then allow time to answer in both places. Cross-posting creates two conversations. It is not native interoperability or follower migration. Publish to Mastodon and Bluesky with a queue that makes both versions reviewable.
Where Nostr fits
Nostr uses signed events and relays. Your key pair identifies you independently of one relay, and clients decide which relays to read or publish to. That makes key backup and safe handling part of normal use. Losing control of a private key is a different problem from forgetting a service password.
Relay operators and clients can apply their own policies and filters; this is not the same governance arrangement as joining a Mastodon instance. Discovery and recovery depend on the client and setup you choose. The protocol repository is the primary starting point. Never paste a private key into a comparison tool, public post or support enquiry.
Sources
The official Mastodon, Bluesky and Nostr sources linked beside the relevant sections support the documented behaviour. Bridging is a third-party workflow with its own consent and moderation limits. Verify the bridge’s current documentation before using it; this guide does not promise complete cross-network interaction.