Adding ActivityPub to Your Homepage

Already have a Solid profile or personal homepage? This guide shows how to add ActivityPub federation using Fedbox, allowing your existing WebID to participate in the Fediverse.

The goal is to unify Solid and ActivityPub with minimal bridging — your identity lives in one place, and Fedbox handles federation.

Overview

Your Homepage (static)              Fedbox Server
────────────────────               ──────────────
https://you.example.com            https://ap.example.com
    /                                  /you/inbox
    /#me  ◄──── identity               /you/outbox
                                       /you/followers

Your homepage hosts your identity. Fedbox handles ActivityPub federation. A single Fedbox instance can handle multiple users.

URI Fragment Identifiers

Both Solid and this approach use URI fragment identifiers (#me) for identity:

https://you.example.com/ — The profile document
https://you.example.com/#me — The WebID (the Person)

This is the Solid convention: the document and the thing it describes are distinct. The fragment #me identifies the person within the document. This allows the same URL to serve both HTML (for browsers) and JSON-LD (for machines) via content negotiation.

The id can be relative — just "#me" — and resolves against the document URL.

Step 1: Add JSON-LD to Your Homepage

Add a data island to your existing HTML:

<!DOCTYPE html>
<html>
<head>
  <title>Your Name</title>
  <script type="application/ld+json">
  {
    "@context": [
      "https://www.w3.org/ns/activitystreams",
      "https://w3id.org/security/v1"
    ],
    "type": "Person",
    "id": "#me",
    "url": "./",
    "preferredUsername": "you",
    "name": "Your Name",
    "summary": "<p>Your bio here</p>",
    "inbox": "https://ap.example.com/you/inbox",
    "outbox": "https://ap.example.com/you/outbox",
    "followers": "https://ap.example.com/you/followers",
    "following": "https://ap.example.com/you/following",
    "publicKey": {
      "id": "#main-key",
      "owner": "#me",
      "publicKeyPem": "-----BEGIN PUBLIC KEY-----\n...\n-----END PUBLIC KEY-----"
    }
  }
  </script>
</head>
<body>
  <!-- Your existing homepage content -->
</body>
</html>

Key points:

id uses relative #me — resolves to https://you.example.com/#me
Fragment IDs are Solid-compatible WebIDs
inbox, outbox, followers point to your Fedbox server
publicKey must match your Fedbox keypair

Step 2: Set Up Fedbox

Deployment Options

Dedicated server (e.g., ap.example.com):

Point DNS A record to your server
Fedbox listens directly, or use a reverse proxy for TLS
Simplest setup — no path routing needed

Shared server (behind existing web server):

Add reverse proxy rules to route AP endpoints to Fedbox
See Reverse Proxy Configuration for nginx, Caddy, and HAProxy examples

Installation

On your server (VPS, cloud instance, etc.):

# Install
npm install -g fedbox

# Initialize
fedbox init

Edit fedbox.json:

{
  "username": "you",
  "displayName": "Your Name",
  "summary": "Your bio",
  "port": 3000,
  "domain": "ap.example.com",
  "profileUrl": "https://you.example.com/",
  "publicKey": "-----BEGIN PUBLIC KEY-----...",
  "privateKey": "-----BEGIN PRIVATE KEY-----..."
}

The profileUrl tells Fedbox to fetch your identity from your homepage.

Step 3: Copy Your Public Key

Get your public key from Fedbox:

cat fedbox.json | grep -A 10 publicKey

Copy this into your homepage's JSON-LD publicKeyPem field.

Step 4: Add WebFinger

For people to find you as @you@you.example.com, add WebFinger to your homepage.

Create /.well-known/webfinger (or configure your server to respond):

{
  "subject": "acct:you@you.example.com",
  "links": [
    {
      "rel": "self",
      "type": "application/activity+json",
      "href": "https://you.example.com/#me"
    }
  ]
}

For static hosts like GitHub Pages, create .well-known/webfinger as a file (no extension).

Step 5: Start Fedbox

fedbox start

Fedbox will:

Fetch your homepage
Extract the JSON-LD data island
Merge with local AP endpoints
Serve with proper content negotiation

Step 6: Test Discovery

From Mastodon, search for @you@you.example.com. You should see your profile with your homepage identity.

How It Works

Mastodon                    Your Homepage              Fedbox
────────                    ─────────────              ──────

GET webfinger ────────────► returns actor href

GET actor ─────────────────► returns JSON-LD ─────────► (or Fedbox serves it)
                            with AP endpoints

POST inbox ──────────────────────────────────────────► receives activities

GET outbox ──────────────────────────────────────────► returns your posts

Optional: Link Nostr Identity

Add your Nostr pubkey to the JSON-LD:

{
  "alsoKnownAs": ["did:nostr:your64charhexpubkey"]
}

And in fedbox.json:

{
  "nostrPubkey": "your64charhexpubkey"
}

Troubleshooting

"Could not fetch remote profile"

Check that your homepage is accessible
Verify the JSON-LD is valid (use jsonlint.com)
Ensure <script type="application/ld+json"> is present

"Signature verification failed"

The public key in your homepage must match Fedbox's keypair
Copy the exact key from fedbox.json

"WebFinger not found"

Ensure .well-known/webfinger is accessible
Check CORS headers if on a different domain
Some static hosts require special configuration for dotfiles

Content Negotiation Issues

The standards-compliant approach is content negotiation: the same URL serves different representations based on the Accept header.

GET /alice
Accept: text/html           →  HTML page
Accept: application/ld+json →  JSON-LD actor

The problem: Static hosts can't do content negotiation — they serve the same file regardless of headers. And some ActivityPub implementations expect JSON when they request application/activity+json, even though JSON-LD data islands in HTML are valid per the JSON-LD spec.

How Fedbox solves this: Fedbox fetches your static HTML profile, extracts the JSON-LD data island, and serves it with proper content negotiation:

Mastodon                        Fedbox                      Your Homepage
────────                        ──────                      ─────────────
GET actor (Accept: JSON) ──────► extracts data island ◄──── static HTML
                          ◄───── returns JSON-LD

Your homepage stays static, but Fedbox provides the content negotiation layer.

Alternative: Use a reverse proxy for content negotiation (see below).

Reverse Proxy Configuration

Proxying to Fedbox

Nginx

upstream fedbox {
    server 127.0.0.1:3000;
}

server {
    listen 443 ssl;
    server_name ap.example.com;

    # ActivityPub endpoints
    location ~ ^/(inbox|nodeinfo|\.well-known) {
        proxy_pass http://fedbox;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }

    location ~ ^/(\w+)/(inbox|outbox|followers|following|posts) {
        proxy_pass http://fedbox;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}

Caddy

ap.example.com {
    reverse_proxy /inbox* localhost:3000
    reverse_proxy /nodeinfo* localhost:3000
    reverse_proxy /.well-known/* localhost:3000
    reverse_proxy /*/inbox localhost:3000
    reverse_proxy /*/outbox localhost:3000
    reverse_proxy /*/followers localhost:3000
    reverse_proxy /*/following localhost:3000
    reverse_proxy /*/posts/* localhost:3000
}

HAProxy

frontend https
    bind *:443 ssl crt /etc/ssl/certs/ap.example.com.pem
    acl is_ap path_beg /inbox /.well-known /nodeinfo
    acl is_ap_user path_reg ^/\w+/(inbox|outbox|followers|following|posts)
    use_backend fedbox if is_ap or is_ap_user

backend fedbox
    server fedbox1 127.0.0.1:3000 check

Content Negotiation via Proxy

If you want to serve both HTML and JSON-LD from the same URL without Fedbox:

Nginx

location /alice {
    if ($http_accept ~* "application/(activity\+json|ld\+json)") {
        rewrite ^ /alice.jsonld last;
    }
    try_files /alice.html =404;
}

location /alice.jsonld {
    default_type application/activity+json;
}

Caddy

example.com {
    @activitypub {
        header Accept *activity+json*
    }
    @activitypub_ld {
        header Accept *ld+json*
    }
    rewrite @activitypub /alice.jsonld
    rewrite @activitypub_ld /alice.jsonld

    header /alice.jsonld Content-Type application/activity+json
    file_server
}

HAProxy

frontend https
    bind *:443 ssl crt /etc/ssl/certs/example.com.pem
    acl accept_json req.hdr(Accept) -m sub activity+json
    acl accept_json req.hdr(Accept) -m sub ld+json

    http-request set-path %[path].jsonld if accept_json { path /alice }
    default_backend static

backend static
    server web1 127.0.0.1:8080 check

Overview​

URI Fragment Identifiers​

Step 1: Add JSON-LD to Your Homepage​

Step 2: Set Up Fedbox​

Deployment Options​

Installation​

Step 3: Copy Your Public Key​

Step 4: Add WebFinger​

Step 5: Start Fedbox​

Step 6: Test Discovery​

How It Works​

Optional: Link Nostr Identity​

Troubleshooting​

"Could not fetch remote profile"​

"Signature verification failed"​

"WebFinger not found"​

Content Negotiation Issues​

Reverse Proxy Configuration​

Proxying to Fedbox​

Nginx​

Caddy​

HAProxy​

Content Negotiation via Proxy​

Nginx​

Caddy​

HAProxy​

See Also​

Overview

URI Fragment Identifiers

Step 1: Add JSON-LD to Your Homepage

Step 2: Set Up Fedbox

Deployment Options

Installation

Step 3: Copy Your Public Key

Step 4: Add WebFinger

Step 5: Start Fedbox

Step 6: Test Discovery

How It Works

Optional: Link Nostr Identity

Troubleshooting

"Could not fetch remote profile"

"Signature verification failed"

"WebFinger not found"

Content Negotiation Issues

Reverse Proxy Configuration

Proxying to Fedbox

Nginx

Caddy

HAProxy

Content Negotiation via Proxy

Nginx

Caddy

HAProxy

See Also