Fedify: an ActivityPub server framework

🎉 Excited to announce that #Fedify is now on Open Collective! Support the project's development starting at:

• Backer (from $5/mo)
• Supporter (from $25/mo)
• Sponsor (from $100/mo)
• Corporate Sponsor (from $500/mo)
• Custom donations welcome

Your support will help us maintain and improve Fedify. Check it out here:

https://opencollective.com/fedify

#OpenCollective #support #backing #sponsor #donation

Fedify is an #ActivityPub server framework in #TypeScript & #JavaScript. It aims to eliminate the complexity and redundant boilerplate code when building a federated server app, so that you can focus on your business logic and user experience.

The key features it provides currently are:

• Type-safe objects for Activity Vocabulary (including some vendor-specific extensions)
• #WebFinger client and server
• HTTP Signatures & Linked Data Signatures & Object Integrity Proofs
• Middleware for handling webhooks
• #NodeInfo protocol
• #Node.js, #Deno, and #Bun support
• CLI toolchain for testing and debugging

If you're curious, take a look at the #Fedify website! There's comprehensive docs, a demo, a tutorial, example code, and more:

https://fedify.dev/

Hello, #fediverse! It's the official fedi account of the Fedify, an #ActivityPub server framework!

#Fedify #fedidev

もしかしたらご存じないかもしれませんが、Fedifyには DiscordとMatrixのコミュニティがあります。ここでは、サポートを受けたり、機能について議論したり、ActivityPubやフェデレーテッドソーシャルネットワークについて話し合うことができます。

• Matrixスペース：#fedify:matrix.org
• Discordサーバー：https://discord.gg/bhtwpzURwd

お好みのコミュニティにご参加ください。どちらのチャンネルでも、Fedifyやフェデレーション関連のトピックについて活発な議論が行われています。

#Fedify #ActivityPub #fedidev #Matrix #Discord

혹시 모르고 계셨다면, Fedify는 Discord와 Matrix 커뮤니티를 운영하고 있습니다. 이곳에서 도움을 받거나, 기능에 대해 논의하거나, ActivityPub와 연합 소셜 네트워크에 대해 대화를 나눌 수 있습니다.

• Matrix 스페이스: #fedify:matrix.org
• Discord 서버: https://discord.gg/bhtwpzURwd

여러분의 선호도에 따라 어느 커뮤니티든 참여해 주세요. 두 채널 모두 Fedify와 연합 관련 주제에 대한 활발한 논의가 이루어지고 있습니다.

#Fedify #fedidev #ActivityPub #Discord #Matrix #디스코드 #매트릭스

In case you weren't aware, #Fedify has both #Discord and #Matrix communities where you can get help, discuss features, or just chat about #ActivityPub and federated social networks.

• Matrix space: #fedify:matrix.org
• Discord server: https://discord.gg/bhtwpzURwd

Feel free to join either community based on your preference. Both channels have active discussions about Fedify and federation topics.

#fedidev

We at @index@www.avant.dev have contributed to @fedify - the framework enabling @index@activitypub.ghost.org integration with the fediverse.

As social networks build walls, Fedify creates critical infrastructure for an open web. Their tools simplify federation protocols, making decentralized communication accessible.

Support: https://opencollective.com/fedify

뭔가 이거 만들다보니까 fedify를 이용한 sns 만들기 스타터킷 같은게 만들어지면 좋을 것 같음.

* 노트 작성
* 팔로/언팔
* 타임라인
* 프로필
* 블락/블락해제

이런 것들이 미리 구현은 되어있고 나머지 기능은 요령껏 채우면 되는

Don't build #ActivityPub from scratch! It's complex. See why using the #Fedify framework is the smarter way to develop for the fediverse in my new post:

https://hackers.pub/@hongminhee/2025/why-use-fedify

#fedidev

So, you're captivated by the fediverse—the decentralized social web powered by protocols like ActivityPub. Maybe you're dreaming of building the next great federated app, a unique space connected to Mastodon, Lemmy, Pixelfed, and more. The temptation to dive deep and implement ActivityPub yourself, from the ground up, is strong. Total control, right? Understanding every byte? Sounds cool!

But hold on a sec. Before you embark on that epic quest, let's talk reality. Implementing ActivityPub correctly isn't just one task; it's like juggling several complex standards while riding a unicycle… blindfolded. It’s hard.

That's where Fedify comes in. It's a TypeScript framework designed to handle the gnarliest parts of ActivityPub development, letting you focus on what makes your app special, not reinventing the federation wheel.

This post will break down the common headaches of DIY ActivityPub implementation and show how Fedify acts as the super-powered pain reliever, starting with the very foundation of how data is represented.

Challenge #1: Data Modeling—Speaking ActivityStreams & JSON-LD Fluently

At its core, ActivityPub relies on the ActivityStreams 2.0 vocabulary to describe actions and objects, and it uses JSON-LD as the syntax to encode this vocabulary. While powerful, this combination introduces significant complexity right from the start.

First, understanding and correctly using the vast ActivityStreams vocabulary itself is a hurdle. You need to model everything—posts (Note, Article), profiles (Person, Organization), actions (Create, Follow, Like, Announce)—using the precise terms and properties defined in the specification. Manual JSON construction is tedious and prone to errors.

Second, JSON-LD, the encoding layer, has specific rules that make direct JSON manipulation surprisingly tricky:

• Missing vs. Empty Array: In JSON-LD, a property being absent is often semantically identical to it being present with an empty array. Your application logic needs to treat these cases equally when checking for values. For example, these two Note objects mean the same thing regarding the name property:

  // No name property
  {
    "@context": "https://www.w3.org/ns/activitystreams",
    "type": "Note",
    "content": "…"
  }

  // Equivalent to:
  {
    "@context": "https://www.w3.org/ns/activitystreams",
    "type": "Note",
    "name": [],
    "content": "…"
  }

• Single Value vs. Array: Similarly, a property holding a single value directly is often equivalent to it holding a single-element array containing that value. Your code must anticipate both representations for the same meaning, like for the content property here:

  // Single value
  {
    "@context": "https://www.w3.org/ns/activitystreams",
    "type": "Note",
    "content": "Hello"
  }

  // Equivalent to:
  {
    "@context": "https://www.w3.org/ns/activitystreams",
    "type": "Note",
    "content": ["Hello"]
  }

• Object Reference vs. Embedded Object: Properties can contain either the full JSON-LD object embedded directly or just a URI string referencing that object. Your application needs to be prepared to fetch the object's data if only a URI is given (a process called dereferencing). These two Announce activities are semantically equivalent (assuming the URIs resolve correctly):

  {
    "@context": "https://www.w3.org/ns/activitystreams",
    "type": "Announce",
    // Embedded objects:
    "actor": {
      "type": "Person",
      "id": "http://sally.example.org/",
      "name": "Sally"
    },
    "object": {
      "type": "Arrive",
      "id": "https://sally.example.com/arrive",
      /* ... */
    }
  }

  // Equivalent to:
  {
    "@context":
    "https://www.w3.org/ns/activitystreams",
    "type": "Announce",
    // URI references:
    "actor": "http://sally.example.org/",
    "object": "https://sally.example.com/arrive"
  }

Attempting to manually handle all these vocabulary rules and JSON-LD variations consistently across your application inevitably leads to verbose, complex, and fragile code, ripe for subtle bugs that break federation.

Fedify tackles this entire data modeling challenge with its comprehensive, type-safe Activity Vocabulary API. It provides TypeScript classes for ActivityStreams types and common extensions, giving you autocompletion and compile-time safety. Crucially, these classes internally manage all the tricky JSON-LD nuances. Fedify's property accessors present a consistent interface—non-functional properties (like tags) always return arrays, functional properties (like content) always return single values or null. It handles object references versus embedded objects seamlessly through dereferencing accessors (like activity.getActor()) which automatically fetch remote objects via URI when needed—a feature known as property hydration. With Fedify, you work with a clean, predictable TypeScript API, letting the framework handle the messy details of AS vocabulary and JSON-LD encoding.

Challenge #2: Discovery & Identity—Finding Your Actors

Once you can model data, you need to make your actors discoverable. This primarily involves the WebFinger protocol (RFC 7033). You'd need to build a server endpoint at /.well-known/webfinger capable of parsing resource queries (like acct: URIs), validating the requested domain against your server, and responding with a precisely formatted JSON Resource Descriptor (JRD). This JRD must include specific links, like a self link pointing to the actor's ActivityPub ID using the correct media type. Getting any part of this wrong can make your actors invisible.

Fedify simplifies this significantly. It automatically handles WebFinger requests based on the actor information you provide through its setActorDispatcher() method. Fedify generates the correct JRD response. If you need more advanced control, like mapping user-facing handles to internal identifiers, you can easily register mapHandle() or mapAlias() callbacks. You focus on defining your actors; Fedify handles making them discoverable.

// Example: Define how to find actors
federation.setActorDispatcher(
  "/users/{username}",
  async (ctx, username) => { /* ... */ }
);
// Now GET /.well-known/webfinger?resource=acct:username@your.domain just works!

Challenge #3: Core ActivityPub Mechanics—Handling Requests and Collections

Serving actor profiles requires careful content negotiation. A request for an actor's ID needs JSON-LD for machine clients (Accept: application/activity+json) but HTML for browsers (Accept: text/html). Handling incoming activities at the inbox endpoint involves validating POST requests, verifying cryptographic signatures, parsing the payload, preventing duplicates (idempotency), and routing based on activity type. Implementing collections (outbox, followers, etc.) with correct pagination adds another layer.

Fedify streamlines all of this. Its core request handler (via Federation.fetch() or framework adapters like @fedify/express) manages content negotiation. You define actors with setActorDispatcher() and web pages with your framework (Hono, Express, SvelteKit, etc.)—Fedify routes appropriately. For the inbox, setInboxListeners() lets you define handlers per activity type (e.g., .on(Follow, ...)), while Fedify automatically handles validation, signature verification, parsing, and idempotency checks using its KV Store. Collection implementation is simplified via dispatchers (e.g., setFollowersDispatcher()); you provide logic to fetch a page of data, and Fedify constructs the correct Collection or CollectionPage with pagination.

// Define inbox handlers
federation.setInboxListeners("/inbox", "/users/{handle}/inbox")
  .on(Follow, async (ctx, follow) => { /* Handle follow */ })
  .on(Undo, async (ctx, undo) => { /* Handle undo */ });

// Define followers collection logic
federation.setFollowersDispatcher(
  "/users/{handle}/followers",
  async (ctx, handle, cursor) => { /* ... */ }
);

Challenge #4: Reliable Delivery & Asynchronous Processing—Sending Activities Robustly

Sending an activity requires more than a simple POST. Networks fail, servers go down. You need robust failure handling and retry logic (ideally with backoff). Processing incoming activities synchronously can block your server. Efficiently broadcasting to many followers (fan-out) requires background processing and using shared inboxes where possible.

Fedify addresses reliability and scalability using its MessageQueue abstraction. When configured (highly recommended), Context.sendActivity() enqueues delivery tasks. Background workers handle sending with automatic retries based on configurable policies (like outboxRetryPolicy). Fedify supports various queue backends (Deno KV, Redis, PostgreSQL, AMQP). For high-traffic fan-out, Fedify uses an optimized two-stage mechanism to distribute the load efficiently.

// Configure Fedify with a persistent queue (e.g., Deno KV)
const federation = createFederation({
  queue: new DenoKvMessageQueue(/* ... */),
  // ...
});
// Sending is now reliable and non-blocking
await ctx.sendActivity({ handle: "myUser" }, recipient, someActivity);

Challenge #5: Security—Avoiding Common Pitfalls

Securing an ActivityPub server is critical. You need to implement HTTP Signatures (draft-cavage-http-signatures-12) for server-to-server authentication—a complex process. You might also need Linked Data Signatures (LDS) or Object Integrity Proofs (OIP) based on FEP-8b32 for data integrity and compatibility. Managing cryptographic keys securely is essential. Lastly, fetching remote resources risks Server-Side Request Forgery (SSRF) if not validated properly.

Fedify is designed with security in mind. It automatically handles the creation and verification of HTTP Signatures, LDS, and OIP, provided you supply keys via setKeyPairsDispatcher(). It includes key management utilities. Crucially, Fedify's default document loader includes built-in SSRF protection, blocking requests to private IPs unless explicitly allowed.

Challenge #6: Interoperability & Maintenance—Playing Nicely with Others

The fediverse is diverse. Different servers have quirks. Ensuring compatibility requires testing and adaptation. Standards evolve with new Federation Enhancement Proposals (FEPs). You also need protocols like NodeInfo to advertise server capabilities.

Fedify aims for broad interoperability and is actively maintained. It includes features like ActivityTransformers to smooth over implementation differences. NodeInfo support is built-in via setNodeInfoDispatcher().

Challenge #7: Developer Experience—Actually Building Your App

Beyond the protocol, building any server involves setup, testing, and debugging. With federation, debugging becomes harder—was the message malformed? Was the signature wrong? Is the remote server down? Is it a compatibility quirk? Good tooling is essential.

Fedify enhances the developer experience significantly. Being built with TypeScript, it offers excellent type safety and editor auto-completion. The fedify CLI is a powerful companion designed to streamline common development tasks.

You can quickly scaffold a new project tailored to your chosen runtime and web framework using fedify init.

For debugging interactions and verifying data, fedify lookup is invaluable. It lets you inspect how any remote actor or object appears from the outside by performing WebFinger discovery and fetching the object's data. Fedify then displays the parsed object structure and properties directly in your terminal. For example, running:

$ fedify lookup @fedify-example@fedify-blog.deno.dev

Will first show progress messages and then output the structured representation of the actor, similar to this:

// Output of fedify lookup command (shows parsed object structure)
Person {
  id: URL "https://fedify-blog.deno.dev/users/fedify-example",
  name: "Fedify Example Blog",
  published: 2024-03-03T13:18:11.857Z, // Simplified timestamp
  summary: "This blog is powered by Fedify, a fediverse server framework.",
  url: URL "https://fedify-blog.deno.dev/",
  preferredUsername: "fedify-example",
  publicKey: CryptographicKey {
    id: URL "https://fedify-blog.deno.dev/users/fedify-example#main-key",
    owner: URL "https://fedify-blog.deno.dev/users/fedify-example",
    publicKey: CryptoKey { /* ... CryptoKey details ... */ }
  },
  // ... other properties like inbox, outbox, followers, endpoints ...
}

This allows you to easily check how data is structured or troubleshoot why an interaction might be failing by seeing the actual properties Fedify parsed.

Testing outgoing activities from your application during development is made much easier with fedify inbox. Running the command starts a temporary local server that acts as a publicly accessible inbox, displaying key information about the temporary actor it creates for receiving messages:

$ fedify inbox
✔ The ephemeral ActivityPub server is up and running: https://<unique_id>.lhr.life/
✔ Sent follow request to @<some_test_account>@activitypub.academy.
╭───────────────┬─────────────────────────────────────────╮
│ Actor handle: │ i@<unique_id>.lhr.life                  │
├───────────────┼─────────────────────────────────────────┤
│   Actor URI:  │ https://<unique_id>.lhr.life/i          │
├───────────────┼─────────────────────────────────────────┤
│  Actor inbox: │ https://<unique_id>.lhr.life/i/inbox    │
├───────────────┼─────────────────────────────────────────┤
│ Shared inbox: │ https://<unique_id>.lhr.life/inbox      │
╰───────────────┴─────────────────────────────────────────╯

Web interface available at: http://localhost:8000/

You then configure your developing application to send an activity to the Actor inbox or Shared inbox URI provided. When an activity arrives, fedify inbox only prints a summary table to your console indicating that a request was received:

╭────────────────┬─────────────────────────────────────╮
│     Request #: │ 2                                   │
├────────────────┼─────────────────────────────────────┤
│ Activity type: │ Follow                              │
├────────────────┼─────────────────────────────────────┤
│  HTTP request: │ POST /i/inbox                       │
├────────────────┼─────────────────────────────────────┤
│ HTTP response: │ 202                                 │
├────────────────┼─────────────────────────────────────┤
│       Details  │ https://<unique_id>.lhr.life/r/2    │
╰────────────────┴─────────────────────────────────────╯

Crucially, the detailed information about the received request—including the full headers (like Signature), the request body (the Activity JSON), and the signature verification status—is only available in the web interface provided by fedify inbox. This web UI allows you to thoroughly inspect incoming activities during development.

When you need to test interactions with the live fediverse from your local machine beyond just sending, fedify tunnel can securely expose your entire local development server temporarily. This suite of tools significantly eases the process of building and debugging federated applications.

Conclusion: Build Features, Not Plumbing

Implementing the ActivityPub suite of protocols from scratch is an incredibly complex and time-consuming undertaking. It involves deep dives into multiple technical specifications, cryptographic signing, security hardening, and navigating the nuances of a diverse ecosystem. While educational, it dramatically slows down the process of building the actual, unique features of your federated application.

Fedify offers a well-architected, secure, and type-safe foundation, handling the intricacies of federation for you—data modeling, discovery, core mechanics, delivery, security, and interoperability. It lets you focus on your application's unique value and user experience. Stop wrestling with low-level protocol details and start building your vision for the fediverse faster and more reliably. Give Fedify a try!

Getting started is straightforward. First, install the Fedify CLI using your preferred method. Once installed, create a new project template by running fedify init your-project-name.

Check out the Fedify tutorials and Fedify manual to learn more. Happy federating!

Fetching remote #ActivityPub objects or actors often involves handling #WebFinger lookups, content negotiation, and then parsing potentially untyped JSON.

With #Fedify, it's much simpler: use Context.lookupObject(). Pass it a URI (e.g., https://instance.tld/users/alice) or a handle (e.g., @alice@instance.tld), and Fedify handles the lookup and content negotiation automatically.

The real power comes from the return value: a type-safe Activity Vocabulary object, not just raw JSON. This allows you to confidently access properties and methods directly. For example, you can safely traverse account moves using .getSuccessor() like this:

let actor = await ctx.lookupObject("@alice@instance.tld");
while (isActor(actor)) {
  const successor = await actor.getSuccessor();
  if (successor == null) break;
  actor = successor;
}
// actor now holds the latest account after moves

This is readily available in handlers where the Context object is provided (like actor dispatchers or inbox listeners).

Focus on your app's logic, not protocol boilerplate!

Learn more: https://fedify.dev/manual/context#looking-up-remote-objects

#fedidev

Fedify 통으로 프롬프트 넣을때 Repomix 설정값은 이렇게 가야겠다.
https://platform.openai.com/docs/models/o3-mini 기준으로 봤을때 Context Window Length는 200K 토큰 정도 되는데, 여기에 어떻게든 쥐어짜내려면 ignore pattern을 요렇게 가는게 좋을 듯

```
docs/**/*.*, src/codegen/__snapshots__/class.test.ts.snap, src/vocab/__snapshots__/vocab.test.ts.snap, CHANGES.md
```

Fedify 프로젝트의 메인테이너로서 2025年(년) 오픈소스 컨트리뷰션 아카데미 參與型(참여형) 멘토團(단)에 選拔(선발)되었습니다!

5月(월) 21日(일)(水(수))부터 6月(월) 22日(일)(日(일))까지 멘티도 募集(모집)한다고 하니 많은 參與(참여) 바랍니다.

📣 Exciting news! Fedify CLI is now available via Homebrew!

If you're using #Homebrew on macOS or #Linuxbrew on Linux, you can now install our CLI toolchain with a simple command:

brew install fedify

This makes it even easier to get started with building your federated server app. Try it out and let us know what you think!

#Fedify #ActivityPub #fedidev #fediverse

그러고보니 문득 생각이 난 건데 해커스.펍이 #hollo (@hollo@hollo.social)와 마찬가지로 @hongminhee@hollo.social 님이 Fedify(@fedify@hollo.social) 기반으로 만든 자체 ActivityPub 소프트웨어라는 걸 알게 된 건 꽤 됐지만 그렇게 규모가 제법 되는 서비스가 저 분 소유의 홈서버에서 돌아가고 있다는 사실을 알게 된 건 얼마 전의 일이다.

Fedify、開発者体験が良すぎて感動した。 #FediLUG

#FediLUG Fedify、デフォルトでObservabilityがあるの本当に有り難い。

FYI Fedify implements FEP-8fcf, so you can just pass the syncCollection: true option to turn on followers collection synchronization if you use Fedify!

https://mastodon.social/@dansup/114225342328813426

We're incredibly honored to announce that #Ghost (@index) has become a formal sponsor of Fedify through Open Collective!

This is a significant milestone for our project, and we're deeply grateful to @johnonolan and the entire Ghost team for their support and recognition of our work in the #ActivityPub ecosystem.

Ghost's social web integration built on #Fedify is a perfect example of how open standards can connect different publishing platforms in the fediverse. Their backing over the past months has been invaluable, and this formal sponsorship will help ensure Fedify remains sustainable as we continue to develop and improve the framework.

If you're building with ActivityPub or interested in federated applications, please consider joining Ghost in supporting open source development through our Open Collective:

https://opencollective.com/fedify

Every contribution, no matter the size, helps us maintain and enhance the tools that make the fediverse more accessible to developers. Thank you for being part of this journey with us! ❤️

We're incredibly honored to announce that #Ghost (@index) has become a formal sponsor of Fedify through Open Collective!

This is a significant milestone for our project, and we're deeply grateful to @johnonolan and the entire Ghost team for their support and recognition of our work in the #ActivityPub ecosystem.

Ghost's social web integration built on #Fedify is a perfect example of how open standards can connect different publishing platforms in the fediverse. Their backing over the past months has been invaluable, and this formal sponsorship will help ensure Fedify remains sustainable as we continue to develop and improve the framework.

If you're building with ActivityPub or interested in federated applications, please consider joining Ghost in supporting open source development through our Open Collective:

https://opencollective.com/fedify

Every contribution, no matter the size, helps us maintain and enhance the tools that make the fediverse more accessible to developers. Thank you for being part of this journey with us! ❤️

Ghost's social web integration is built on the fantastic work of @hongminhee and the Fedify.dev framework.

We've been backing work on the project for 6 months or so, and now we're thrilled to be formal sponsor of the project on Open Collective!

If you're building with Fedify and ActivityPub, please consider joining us to keep helping to make great open source work sustainable ❤️ Every little helps

https://opencollective.com/fedify

We're excited to announce the release of Fedify 1.5.0! This version brings several significant improvements to performance, configurability, and developer experience. Let's dive into what's new:

Two-Stage Fan-out Architecture for Efficient Activity Delivery

#Fedify now implements a smart fan-out mechanism for delivering activities to large audiences. This change is particularly valuable for accounts with many followers. When sending activities to many recipients, Fedify now creates a single consolidated message containing the activity payload and recipient list, which a background worker then processes to re-enqueue individual delivery tasks.

This architectural improvement delivers several benefits: Context.sendActivity() returns almost instantly even with thousands of recipients, memory consumption is dramatically reduced by avoiding payload duplication, UI responsiveness improves since web requests complete quickly, and the system maintains reliability with independent retry logic for each delivery.

For specific requirements, we've added a new fanout option with three settings:

// Configuring fan-out behavior
await ctx.sendActivity(
  { identifier: "alice" },
  recipients,
  activity,
  { fanout: "auto" }  // Default: automatic based on recipient count
  // Other options: "skip" (never use fan-out) or "force" (always use fan-out)
);

Canonical Origin Support for Multi-Domain Setups

You can now explicitly configure a canonical origin for your server, which is especially useful for multi-domain setups. This feature allows you to set different domains for WebFinger handles and #ActivityPub URIs, configured through the new origin option in createFederation(). This enhancement prevents unexpected URL construction when requests bypass proxies and improves security by ensuring consistent domain usage.

const federation = createFederation({
  // Use example.com for handles but ap.example.com for ActivityPub URIs
  origin: {
    handleHost: "example.com",
    webOrigin: "https://ap.example.com",
  },
  // Other options...
});

Optional Followers Collection Synchronization

Followers collection synchronization (FEP-8fcf) is now opt-in rather than automatic. This feature must now be explicitly enabled through the syncCollection option, giving developers more control over when to include followers collection digests. This change improves network efficiency by reducing unnecessary synchronization traffic.

await ctx.sendActivity(
  { identifier: sender },
  "followers",
  activity,
  { 
    preferSharedInbox: true,
    syncCollection: true,  // Explicitly enable collection synchronization
  }
);

Enhanced Key Format Compatibility

Key format support has been expanded for better interoperability. Fedify now accepts PEM-PKCS#1 format in addition to PEM-SPKI for RSA public keys. We've added importPkcs1() and importPem() functions for additional flexibility, which improves compatibility with a wider range of ActivityPub implementations.

Improved Key Selection Logic

The key selection process is now more intelligent. The fetchKey() function can now select the public key of an actor if keyId has no fragment and the actor has only one public key. This enhancement simplifies key handling in common scenarios and provides better compatibility with implementations that don't specify fragment identifiers.

New Authorization Options

Authorization handling has been enhanced with new options for the RequestContext.getSignedKey() and getSignedKeyOwner() methods. This provides more flexible control over authentication and authorization flows. We've deprecated older parameter-based approaches in favor of the more flexible method-based approach.

Efficient Bulk Message Queueing

Message queue performance is improved with bulk operations. We've added an optional enqueueMany() method to the MessageQueue interface, enabling efficient queueing of multiple messages in a single operation. This reduces overhead when processing batches of activities. All our message queue implementations have been updated to support this new operation:

• @fedify/redis 0.4.0
• @fedify/postgres 0.3.0
• @fedify/amqp 0.2.0

If you're using any of these packages, make sure to update them alongside Fedify to take advantage of the more efficient bulk message queueing.

CLI Improvements

The Fedify command-line tools have been enhanced with an improved web interface for the fedify inbox command. We've added the Fedify logo with the cute dinosaur at the top of the page and made it easier to copy the fediverse handle of the ephemeral actor. We've also fixed issues with the web interface when installed via deno install from JSR.

Additional Improvements and Bug Fixes

• Updated dependencies, including @js-temporal/polyfill to 0.5.0 for Node.js and Bun
• Fixed bundler errors with uri-template-router on Rollup
• Improved error handling and logging for document loader when KV store operations fail
• Added more log messages using the LogTape library
• Internalized the multibase package for better maintenance and compatibility

For the complete list of changes, please refer to the changelog.

To update to Fedify 1.5.0, run:

# For Deno
deno add jsr:@fedify/fedify@1.5.0

# For npm
npm  add     @fedify/fedify@1.5.0

# For Bun
bun  add     @fedify/fedify@1.5.0

Thank you to all contributors who helped make this release possible!

#fedidev #fediverse

I received a heartwarming #testimonial about #Fedify today!

@bgl shared in the FediDev KR Discord server:

I had trouble finding good resources explaining ActivityPub, but after reading through the Fedify docs from start to finish, I feel like I've actually digested it.

They also posted on their Hackers' Pub:

If you want to learn ActivityPub efficiently, just read the Fedify docs from beginning to end.

This makes all the documentation work worthwhile. Glad our docs are helping people understand not just Fedify, but #ActivityPub itself.

#fedidev #fediverse

ActivityPub 효율적으로 익히려면 그냥 fedify 문서 첨부터 끝까지 읽으면 되는듯요

We're excited to announce the release of Fedify 1.5.0! This version brings several significant improvements to performance, configurability, and developer experience. Let's dive into what's new:

Two-Stage Fan-out Architecture for Efficient Activity Delivery

#Fedify now implements a smart fan-out mechanism for delivering activities to large audiences. This change is particularly valuable for accounts with many followers. When sending activities to many recipients, Fedify now creates a single consolidated message containing the activity payload and recipient list, which a background worker then processes to re-enqueue individual delivery tasks.

This architectural improvement delivers several benefits: Context.sendActivity() returns almost instantly even with thousands of recipients, memory consumption is dramatically reduced by avoiding payload duplication, UI responsiveness improves since web requests complete quickly, and the system maintains reliability with independent retry logic for each delivery.

For specific requirements, we've added a new fanout option with three settings:

// Configuring fan-out behavior
await ctx.sendActivity(
  { identifier: "alice" },
  recipients,
  activity,
  { fanout: "auto" }  // Default: automatic based on recipient count
  // Other options: "skip" (never use fan-out) or "force" (always use fan-out)
);

Canonical Origin Support for Multi-Domain Setups

You can now explicitly configure a canonical origin for your server, which is especially useful for multi-domain setups. This feature allows you to set different domains for WebFinger handles and #ActivityPub URIs, configured through the new origin option in createFederation(). This enhancement prevents unexpected URL construction when requests bypass proxies and improves security by ensuring consistent domain usage.

const federation = createFederation({
  // Use example.com for handles but ap.example.com for ActivityPub URIs
  origin: {
    handleHost: "example.com",
    webOrigin: "https://ap.example.com",
  },
  // Other options...
});

Optional Followers Collection Synchronization

Followers collection synchronization (FEP-8fcf) is now opt-in rather than automatic. This feature must now be explicitly enabled through the syncCollection option, giving developers more control over when to include followers collection digests. This change improves network efficiency by reducing unnecessary synchronization traffic.

await ctx.sendActivity(
  { identifier: sender },
  "followers",
  activity,
  { 
    preferSharedInbox: true,
    syncCollection: true,  // Explicitly enable collection synchronization
  }
);

Enhanced Key Format Compatibility

Key format support has been expanded for better interoperability. Fedify now accepts PEM-PKCS#1 format in addition to PEM-SPKI for RSA public keys. We've added importPkcs1() and importPem() functions for additional flexibility, which improves compatibility with a wider range of ActivityPub implementations.

Improved Key Selection Logic

The key selection process is now more intelligent. The fetchKey() function can now select the public key of an actor if keyId has no fragment and the actor has only one public key. This enhancement simplifies key handling in common scenarios and provides better compatibility with implementations that don't specify fragment identifiers.

New Authorization Options

Authorization handling has been enhanced with new options for the RequestContext.getSignedKey() and getSignedKeyOwner() methods. This provides more flexible control over authentication and authorization flows. We've deprecated older parameter-based approaches in favor of the more flexible method-based approach.

Efficient Bulk Message Queueing

Message queue performance is improved with bulk operations. We've added an optional enqueueMany() method to the MessageQueue interface, enabling efficient queueing of multiple messages in a single operation. This reduces overhead when processing batches of activities. All our message queue implementations have been updated to support this new operation:

• @fedify/redis 0.4.0
• @fedify/postgres 0.3.0
• @fedify/amqp 0.2.0

If you're using any of these packages, make sure to update them alongside Fedify to take advantage of the more efficient bulk message queueing.

CLI Improvements

The Fedify command-line tools have been enhanced with an improved web interface for the fedify inbox command. We've added the Fedify logo with the cute dinosaur at the top of the page and made it easier to copy the fediverse handle of the ephemeral actor. We've also fixed issues with the web interface when installed via deno install from JSR.

Additional Improvements and Bug Fixes

• Updated dependencies, including @js-temporal/polyfill to 0.5.0 for Node.js and Bun
• Fixed bundler errors with uri-template-router on Rollup
• Improved error handling and logging for document loader when KV store operations fail
• Added more log messages using the LogTape library
• Internalized the multibase package for better maintenance and compatibility

For the complete list of changes, please refer to the changelog.

To update to Fedify 1.5.0, run:

# For Deno
deno add jsr:@fedify/fedify@1.5.0

# For npm
npm  add     @fedify/fedify@1.5.0

# For Bun
bun  add     @fedify/fedify@1.5.0

Thank you to all contributors who helped make this release possible!

#fedidev #fediverse

I just discovered why some of my followers from larger #Mastodon instances (like mastodon.social) would mysteriously unfollow me after a while!

A pull request was just merged in Mastodon that fixes a critical bug in their follower synchronization mechanism.

Turns out Mastodon implements the FEP-8fcf specification (Followers collection synchronization across servers), but it expected all followers to be in a single page collection. When followers were split across multiple pages, it would only see the first page and incorrectly remove all followers from subsequent pages!

This explains so much about the strange behavior I've been seeing with #Hollo and other #Fedify-based servers over the past few months. Some people would follow me from large instances, then mysteriously unfollow later without any action on their part.

Thankfully this fix has been marked for backporting, so it should appear in an upcoming patch release rather than waiting for the next major version. Great news for all of us building on #ActivityPub!

This is why I love open source—we can identify, understand, and fix these kinds of interoperability issues together. 😊

#fediverse #fedidev

Excited to see the #FediLUG (#Fediverse Linux Users Group) in #Japan organizing a reading club for our Creating your own federated microblog tutorial! 🎉 Their first session is coming up, where participants will work through creating their own #ActivityPub-compatible microblog using #Fedify. Thanks for spreading the word about Fedify in Japan! 🇯🇵

Check out their event on Connpass!

https://msky.ospn.jp/notes/a5re87hzi7s80062

Excited to see the #FediLUG (#Fediverse Linux Users Group) in #Japan organizing a reading club for our Creating your own federated microblog tutorial! 🎉 Their first session is coming up, where participants will work through creating their own #ActivityPub-compatible microblog using #Fedify. Thanks for spreading the word about Fedify in Japan! 🇯🇵

Check out their event on Connpass!

https://msky.ospn.jp/notes/a5re87hzi7s80062

【輪読会試験開催のお知らせ】
本日、 #FediLUG ​:fedilug:​ 輪読会📖第0弾として
「〜自分でActivityPub対応SNSを作ってみよう〜『自分だけのフェディバースのマイクロブログを作ろう！』輪読会」
https://github.com/dahlia/fedify-microblog-tutorial-ja

を行います！申し込みは以下からできます！ぜひ参加してフィードバックをください！！
https://fedilug.connpass.com/event/348240/

Theres a new interview with @hongminhee (of @fedify, @hollo, and now #Ghost fame). It's in with Korean subtitles but quite readable with YouTube's autogenerated English subs.

https://www.youtube.com/watch?v=sqxR8zscSDo

https://hollo.social/@hongminhee/0195a85a-6a29-71fa-a60f-3e79c1295b05 #fediverse #fedidev

@silverpill You've touched on a good point. Since Fedify abstracts the message queue, the performance characteristics depend on the backend you're using (Redis, PostgreSQL, AMQP, etc.). Some backends might support batch operations, but we need to maintain compatibility with all supported queue implementations, which often means separate write operations.

Your concern about sequential processing is valid. Our new approach actually addresses this by maintaining individual recipient messages in the second stage, so slow servers don't block others.

What we've found is that maintaining the (activity, single recipient) pattern in the final queue gives you the best of both worlds: fast API responses via the fan-out queue, plus independent delivery processing. This way, a slow server only affects its own delivery task.

@silverpill The bottleneck happens because for each recipient, we need to:

1. Serialize the activity data
2. Create a queue message with metadata
3. Write to queue storage

When you have thousands of followers, these operations add up quickly and block the HTTP response. With fan-out, we only do this once during the request.

What issues are you having with your current fan-out implementation? We're always looking to improve ours.

Coming soon in #Fedify 1.5.0: Smart fan-out for efficient activity delivery!

After getting feedback about our queue design, we're excited to introduce a significant improvement for accounts with large follower counts.

As we discussed in our previous post, Fedify currently creates separate queue messages for each recipient. While this approach offers excellent reliability and individual retry capabilities, it causes performance issues when sending activities to thousands of followers.

Our solution? A new two-stage “fan-out” approach:

1. When you call Context.sendActivity(), we'll now enqueue just one consolidated message containing your activity payload and recipient list
2. A background worker then processes this message and re-enqueues individual delivery tasks

The benefits are substantial:

• Context.sendActivity() returns almost instantly, even for massive follower counts
• Memory usage is dramatically reduced by avoiding payload duplication
• UI responsiveness improves since web requests complete quickly
• The same reliability for individual deliveries is maintained

For developers with specific needs, we're adding a fanout option with three settings:

• "auto" (default): Uses fanout for large recipient lists, direct delivery for small ones
• "skip": Bypasses fanout when you need different payload per recipient
• "force": Always uses fanout even with few recipients

// Example with custom fanout setting
await ctx.sendActivity(
  { identifier: "alice" },
  recipients,
  activity,
  { fanout: "skip" }  // Directly enqueues individual messages
);

This change represents months of performance testing and should make Fedify work beautifully even for extremely popular accounts!

For more details, check out our docs.

What other #performance optimizations would you like to see in future Fedify releases?

#ActivityPub #fedidev