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wanderer Documentation

Federation

wanderer is a federated trail-sharing platform built on ActivityPub. It enables users to publish trails, follow other explorers across instances, and interact with content such as comments, lists, and summit logs. All user-generated content in wanderer—whether it’s a trail, a list, a comment, or a summit log—is modeled as a Note object in ActivityPub, adhering to a consistent structure for federation.

This technical documentation provides a detailed overview of how federation works in wanderer, including the types of objects exchanged, the structure of those objects, and how interactions such as mentions, likes, and follows are processed across instances.

Below, you’ll find examples of the different JSON representations used in federated communication. These illustrate how wanderer encodes and interprets core actions and content as standardized Note objects.

Context

Section titled “Context”
"@context":[
    "https://www.w3.org/ns/activitystreams"
]

The context is identical for all activities and objects.

Actors

Section titled “Actors”

An actor represents a user of wanderer in a federated context.

Person

Section titled “Person”
{
    "id": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
    "type": "Person",
    "inbox": "https://demo.wanderer.to/api/v1/activitypub/user/demo/inbox",
    "outbox": "https://demo.wanderer.to/api/v1/activitypub/user/demo/outbox",
    "summary": "Born the day we installed the site.",
    "name": "demo",
    "preferredUsername": "demo",
    "followers": "https://demo.wanderer.to/api/v1/activitypub/user/demo/followers",
    "following": "https://demo.wanderer.to/api/v1/activitypub/user/demo/following",
    "url": "https://demo.wanderer.to/profile/@demo",
    "published": "2025-05-05T15:07:59.943Z",
    "icon": {
        "type": "Image",
        "url": "https://demo.wanderer.to/api/v1/files/users/26b1si1344ficl6/wlezq_um7vh2722q.jpg"
    },
    "publicKey": {
        "id": "https://demo.wanderer.to/api/v1/activitypub/user/demo#main-key",
        "owner": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
        "publicKeyPem": "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAw0xyaRWP5X955bwSnUbr\nmwEF/2Fdmn5nlRRmEvej1BR0oBcPMVPYrrK4sz37mrAJ7Wbmg4KjmSDEROD4sApr\nM5FmKeU1OBsV2O3bL1DSW/8PXaf4JQRgl0AO+LiSAd7A/GO0viAzJXyJT4Rpaamf\n8Naclh7YR5E4JXrsjahPEWtUWcQ4g8Yhc6n2ptQ33ACI7Q1R3+U7q1tMaRCKAbdT\nbRahzqGs3iSxV+FjnsMR109KqDQJDMjwRB11USJTA4/nMpV6w8RS+171xNHl12Sg\nGpiuusmXMYYuoECdKDtLY7AsntusYMzXUjPzKfE+5EqPmIj5OTbg3A24p9hWIv5s\nmwIDAQAB\n-----END PUBLIC KEY-----\n"
    }
}

Outbox

Section titled “Outbox”

Paginated outbox of an actor.

{
    "type": "OrderedCollectionPage",
    "first": "https://demo.wanderer.to/api/v1/activitypub/user/demo/outbox?page=1",
    "next": "https://demo.wanderer.to/api/v1/activitypub/user/demo/outbox?page=2",
    "partOf": "https://demo.wanderer.to/api/v1/activitypub/user/demo/outbox",
    "totalItems": 23,
    "orderedItems": [
        {
            "id": "https://demo.wanderer.to/api/v1/activitypub/activity/ecy96j9vpke00hr",
            "actor": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
            "type": "Create",
            "to": [
                "https://www.w3.org/ns/activitystreams#Public"
            ],
            "cc": [
                "https://social.tchncs.de/users/flomp/inbox",
                "https://demo.wanderer.to/api/v1/activitypub/user/demo/inbox"
            ],
            "published": "2025-06-20 19:41:53.504Z",
            "object": {
                "id": "https://demo.wanderer.to/api/v1/comment/htm169g4b2i48fc",
                "type": "Note",
                "content": "<p><a href=\"/profile/@flomp@social.tchncs.de\" class=\"mention\" rel=\"nofollow\">@flomp@social.tchncs.de</a> </p><p>Wow! What a beautiful trail!</p>",
                "attributedTo": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
                "inReplyTo": "https://demo.wanderer.to/api/v1/trail/2ce3af7a2e80f52",
                "tag": [
                    {
                        "id": "https://social.tchncs.de/users/flomp",
                        "type": "Mention",
                        "name": "@flomp@social.tchncs.de",
                        "href": "https://social.tchncs.de/users/flomp"
                    }
                ],
                "published": "2025-06-20T19:41:53Z"
            }
        }
    ]
}

Followers

Section titled “Followers”

Paginated collection of followers of an actor.

{
    "type": "OrderedCollectionPage",
    "first": "https://demo.wanderer.to/api/v1/activitypub/user/demo/followers?page=1",
    "partOf": "https://demo.wanderer.to/api/v1/activitypub/user/demo/followers",
    "totalItems": 3,
    "orderedItems": [
        "https://social.tchncs.de/users/flomp",
        "https://trails.magdeburg.jetzt/api/v1/activitypub/user/momar",
        "https://darmstadt.social/users/stormii"
    ]
}

Following

Section titled “Following”

Paginated collection of actors being followed by an actor.

{
    "type": "OrderedCollectionPage",
    "first": "https://demo.wanderer.to/api/v1/activitypub/user/demo/following?page=1",
    "partOf": "https://demo.wanderer.to/api/v1/activitypub/user/demo/following",
    "totalItems": 3,
    "orderedItems": [
        "https://social.tchncs.de/users/milan",
        "https://social.tchncs.de/users/flomp",
        "https://trails.tchncs.de/api/v1/activitypub/user/milan"
    ]
}

Objects

Section titled “Objects”

Trail

Section titled “Trail”

Represents a trail with various metadata like description, photos, elevation data etc.

{
    "id": "https://demo.wanderer.to/api/v1/trail/2ce3af7a2e80f52",
    "type": "Note",
    "name": "12 days in the Zugspitz region on the peak hiking trail",
    "content": "<h1>12 days in the Zugspitz region on the peak hiking trail</h1><p><a href=\"/profile/@flomp@social.tchncs.de\" class=\"mention\" rel=\"nofollow\">@flomp@social.tchncs.de</a> </p><p><a href=\"https://demo.wanderer.to/trail/view/@demo/2ce3af7a2e80f52\">https://demo.wanderer.to/trail/view/@demo/2ce3af7a2e80f52</a></p>",
    "attachment": [
        {
            "type": "Image",
            "mediaType": "image/jpeg",
            "url": "https://demo.wanderer.to/api/v1/files/trails/2ce3af7a2e80f52/route_ldv172t0my.webp"
        },
        {
            "type": "Document",
            "mediaType": "application/xml+gpx",
            "url": "https://demo.wanderer.to/api/v1/files/trails/2ce3af7a2e80f52/12_days_in_the_zugspitz_region_on_the_peak_hiking_trail_5ts04zgsuk.gpx"
        }
    ],
    "attributedTo": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
    "location": {
        "type": "Place",
        "name": "Murnau am Staffelsee, Bayern, Deutschland",
        "latitude": 47.678592,
        "longitude": 11.196068
    },
    "tag": [
        {
            "type": "Note",
            "name": "category",
            "content": "Biking"
        },
        {
            "type": "Note",
            "name": "difficulty",
            "content": "easy"
        },
        {
            "type": "Note",
            "name": "elevation_gain",
            "content": "8902.000000m"
        },
        {
            "type": "Note",
            "name": "elevation_loss",
            "content": "8906.000000m"
        },
        {
            "type": "Note",
            "name": "distance",
            "content": "202403.824936m"
        },
        {
            "type": "Note",
            "name": "duration",
            "content": "4037.183333m"
        },
        {
            "id": "https://social.tchncs.de/users/flomp",
            "type": "Mention",
            "name": "@flomp@social.tchncs.de",
            "href": "https://social.tchncs.de/users/flomp"
        },
        {
            "type": "Note",
            "name": "tag",
            "content": "My awesome tag"
        }
    ],
    "url": "https://demo.wanderer.to/trail/view/@demo/2ce3af7a2e80f52",
    "published": "2025-06-17T21:40:02Z",
    "startTime": "2025-06-14T00:00:00Z"
}

Summit log

Section titled “Summit log”

Represents a summit log that is attached to a trail. The trail is referenced in the “InReplyTo” field. It contains very similar metadata to a trail object.

{
  "id": "https://demo.wanderer.to/api/v1/summit-log/0l889g7nbju9ic2",
  "type": "Note",
  "content": "<p>Hello World! This is a summit log!</p><p><a href=\"/profile/@flomp@social.tchncs.de\" class=\"mention\" rel=\"nofollow\">@flomp@social.tchncs.de</a> </p>",
  "attachment": [
    {
      "type": "Image",
      "mediaType": "image/jpeg",
      "url": "https://demo.wanderer.to/api/v1/files/summit_logs/0l889g7nbju9ic2/walchensee_heimgarten_fahrenbergkopf_herzogstand_2020_10_25_loncv4fixp.jpg"
    },
    {
      "type": "Document",
      "mediaType": "application/xml+gpx",
      "url": "https://demo.wanderer.to/api/v1/files/summit_logs/0l889g7nbju9ic2/12_days_in_the_zugspitz_region_on_the_peak_hiking_trail_8mw5gysia0.gpx"
    }
  ],
  "attributedTo": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
  "inReplyTo": "https://demo.wanderer.to/api/v1/trail/2ce3af7a2e80f52",
  "tag": [
    {
      "type": "Note",
      "name": "elevation_gain",
      "content": "6343.200000m"
    },
    {
      "type": "Note",
      "name": "elevation_loss",
      "content": "6347.400000m"
    },
    {
      "type": "Note",
      "name": "distance",
      "content": "202403.824936m"
    },
    {
      "type": "Note",
      "name": "duration",
      "content": "242231.000000m"
    },
    {
      "id": "https://social.tchncs.de/users/flomp",
      "type": "Mention",
      "name": "@flomp@social.tchncs.de",
      "href": "https://social.tchncs.de/users/flomp"
    }
  ],
  "url": "https://demo.wanderer.to/trail/view/@demo/2ce3af7a2e80f52",
  "published": "2025-06-20T19:38:19Z",
  "startTime": "2025-06-20T00:00:00Z"
}

Comment

Section titled “Comment”

A comment attached to a trail. The trail is referenced in the “InReplyTo” field. Contains only text.

{
  "id": "https://demo.wanderer.to/api/v1/comment/htm169g4b2i48fc",
  "type": "Note",
  "content": "<p><a href=\"/profile/@flomp@social.tchncs.de\" class=\"mention\" rel=\"nofollow\">@flomp@social.tchncs.de</a> </p><p>Wow! What a beautiful trail!</p>",
  "attributedTo": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
  "inReplyTo": "https://demo.wanderer.to/api/v1/trail/2ce3af7a2e80f52",
  "tag": [
    {
      "id": "https://social.tchncs.de/users/flomp",
      "type": "Mention",
      "name": "@flomp@social.tchncs.de",
      "href": "https://social.tchncs.de/users/flomp"
    }
  ],
  "published": "2025-06-20T19:41:53Z"
}

List

Section titled “List”

A collection of trails.

{
  "id": "https://demo.wanderer.to/api/v1/list/65i686yf6u3b394",
  "type": "Note",
  "name": "My Awesome List",
  "content": "<p>With my awesome description.</p><p><a href=\"https://demo.wanderer.to/lists/@demo/65i686yf6u3b394\">https://demo.wanderer.to/lists/@demo/65i686yf6u3b394</a></p>",
  "attachment": [
    {
      "type": "Image",
      "mediaType": "image/jpeg",
      "url": "https://demo.wanderer.to/api/v1/files/lists/65i686yf6u3b394/walchensee_heimgarten_fahrenbergkopf_herzogstand_2020_10_25_m1ubtj7rwk.jpg"
    }
  ],
  "attributedTo": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
  "url": "https://demo.wanderer.to/lists/@demo/65i686yf6u3b394",
  "published": "2025-05-18T22:03:19Z"
}

Activities

Section titled “Activities”

Create or Update trail

Section titled “Create or Update trail”

Issued whenever a trail is created or updated. Broadcasted to all followers and all mentions. Editing a previously created trail will broadcast an identical activity, except the type being Update. The object is a Trail.

{
    "id": "https://demo.wanderer.to/api/v1/activitypub/activity/wqt6poxjevq9oax",
    "actor": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
    "type": "Create",
    "to": [
        "https://www.w3.org/ns/activitystreams#Public"
    ],
    "cc": [
        "https://demo.wanderer.to/api/v1/activitypub/user/demo/followers",
        "https://social.tchncs.de/users/flomp/inbox"
    ],
    "published": "2025-06-15 14:56:38.800Z",
    "object": {}
}

Create or Update summit log

Section titled “Create or Update summit log”

Issued whenever a summit log is created or updated. Broadcasted to the trail author, the author’s followers and all mentions. Editing a previously created summit log will broadcast an identical activity, except the type being Update. The object is a Summit Log.

{
    "id": "https://demo.wanderer.to/api/v1/activitypub/activity/i31uc0lki3crxwm",
    "actor": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
    "to": "https://www.w3.org/ns/activitystreams#Public",
    "type": "Create",
    "cc": [
        "https://demo.wanderer.to/api/v1/activitypub/user/demo/followers",
        "https://social.tchncs.de/users/flomp/inbox"
    ],
    "published": "2025-06-20 19:38:19.978Z",
    "object": {}
}

Create or Update comment

Section titled “Create or Update comment”

Issued whenever a comment is created or updated. Broadcasted to the trail’s author and all mentions. Editing a previously created comment will broadcast an identical activity, except the type being Update. The object is a Comment.

{
    "id": "https://demo.wanderer.to/api/v1/activitypub/activity/ecy96j9vpke00hr",
    "actor": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
    "type": "Create",
    "to": [
        "https://www.w3.org/ns/activitystreams#Public"
    ],
    "cc": [
        "https://social.tchncs.de/users/flomp/inbox",
        "https://demo.wanderer.to/api/v1/activitypub/user/demo/inbox"
    ],
    "published": "2025-06-20 19:41:53.504Z",
    "object": {}
}

Create or Update list

Section titled “Create or Update list”

Issued whenever a list is created or updated. Broadcasted to all followers. Editing a previously created list will broadcast an identical activity, except the type being Update. The object is a List.

{
    "id": "https://demo.wanderer.to/api/v1/activitypub/activity/zq30he84ng9of67",
    "actor": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
    "type": "Create",
    "to": [
        "https://www.w3.org/ns/activitystreams#Public"
    ],
    "cc": [
        "https://demo.wanderer.to/api/v1/activitypub/user/demo/followers",
    ],
    "published": "2025-06-20 19:51:37.079Z",
    "object": {}
}

Follow user

Section titled “Follow user”

Each actor in wanderer can be followed. The actor being followed will immediately send back an Accept activity. Future public trails and lists published by the actor being followed will be broadcasted to the following actors inbox.

{
    "id": "https://demo.wanderer.to/api/v1/activitypub/activity/ika3t06qjyvlx72",
    "actor": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
    "type": "Follow",
    "to": null,
    "cc": null,
    "published": "2025-06-01 07:23:56.517Z",
    "object": "https://social.tchncs.de/users/flomp"
}

Accept follow

Section titled “Accept follow”

Automatically send by an actor as a response upon receiving a Follow activity.

{
    "id": "https://demo.wanderer.to/api/v1/activitypub/activity/9jpjjvvi79ayp9d",
    "actor": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
    "type": "Accept",
    "to": null,
    "cc": null,
    "published": "2025-06-17 19:48:29.417Z",
    "object": {
        "id": "https://social.tchncs.de/8f702e81-9f85-419f-8e45-c44c8b6d8365",
        "type": "Follow",
        "actor": "https://social.tchncs.de/users/flomp",
        "object": "https://demo.wanderer.to/api/v1/activitypub/user/demo"
    }
}

Undo follow

Section titled “Undo follow”

An unfollow is represented by an Undo activity with the original follow as its object.

{
    "id": "https://demo.wanderer.to/api/v1/activitypub/activity/n3n7ka5msa3il84",
    "actor": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
    "type": "Undo",
    "to": null,
    "cc": null,
    "published": "2025-06-20 20:14:37.107Z",
    "object": {
        "id": "https://demo.wanderer.to/api/v1/activitypub/activity/ika3t06qjyvlx72",
        "type": "Follow",
        "actor": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
        "object": "https://social.tchncs.de/users/flomp"
    }
}

Like trail

Section titled “Like trail”

A like for a trail.

{
    "id": "https://demo.wanderer.to/api/v1/activitypub/activity/jjlcgm0il3jy2y7",
    "actor": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
    "type": "Like",
    "to": null,
    "cc": null,
    "published": "2025-06-18 18:48:55.300Z",
    "object": "https://demo.wanderer.to/api/v1/trail/23fd1747a29c3af"
}

Undo like trail

Section titled “Undo like trail”

Removing a like from a previously liked trail.

{
    "id": "https://demo.wanderer.to/api/v1/activitypub/activity/jjlcgm0il3jy2y7",
    "actor": "https://demo.wanderer.to/api/v1/activitypub/user/demo",
    "type": "Undo",
    "to": null,
    "cc": null,
    "published": "2025-06-18 18:48:55.300Z",
    "object": "https://demo.wanderer.to/api/v1/trail/23fd1747a29c3af"
}