Sync API docs from bc3: add and remove clients on a project (PUT /projects/:id/people/client_users, client_enablement)

README.md

@@ -284,6 +284,7 @@ API endpoints
 <!-- START API ENDPOINTS -->
 - [Account](sections/account.md#account)
 - [Attachments](sections/attachments.md#attachments)
+- [Backlinks](sections/backlinks.md#backlinks)
 - [Boosts](sections/boosts.md#boosts)
 - [Calendars](sections/calendars.md#calendars)
 - [Campfires](sections/campfires.md#campfires)
@@ -333,10 +334,12 @@ API endpoints
 - [Search](sections/search.md#search)
 - [Spotlights](sections/spotlights.md#spotlights)
 - [Subscriptions](sections/subscriptions.md#subscriptions)
+- [Subtasks](sections/subtasks.md#subtasks)
 - [Templates](sections/templates.md#templates)
 - [Timeline](sections/timeline.md#timeline)
 - [Timesheets](sections/timesheets.md#timesheets)
 - [To-do list groups](sections/todolist_groups.md#to-do-list-groups)
+- [To-do list templates](sections/template_library.md#to-do-list-templates)
 - [To-do lists](sections/todolists.md#to-do-lists)
 - [To-do sets](sections/todosets.md#to-do-sets)
 - [To-dos](sections/todos.md#to-dos)

sections/backlinks.md

@@ -0,0 +1,88 @@
+Backlinks
+=========
+
+A backlink records that one [recording][recordings] references another in its rich text content. The backlinks endpoint lists the recordings that reference a given recording — the "references to this" shown in the Basecamp UI.
+
+Only backlinks from projects and pings the current user can access are returned, so two people requesting the same recording's backlinks may see different lists.
+
+Endpoints:
+
+- [Get backlinks](#get-backlinks)
+
+Get backlinks
+-------------
+
+* `GET /recordings/2/backlinks.json` will return the most recent 20 recordings that reference the recording with an ID of `2`, newest first.
+
+Each entry is a [recording][recordings] — the referencing recording, not the backlink itself.
+
+###### Example JSON Response
+```json
+[
+  {
+    "id": 1069480024,
+    "status": "active",
+    "visible_to_clients": false,
+    "created_at": "2026-07-19T14:22:11.000Z",
+    "updated_at": "2026-07-19T14:22:11.000Z",
+    "title": "Finalize launch checklist",
+    "inherits_status": true,
+    "type": "Todo",
+    "url": "https://3.basecampapi.com/195539477/buckets/2085958505/todos/1069480024.json",
+    "app_url": "https://3.basecamp.com/195539477/buckets/2085958505/todos/1069480024",
+    "bookmark_url": "https://3.basecampapi.com/195539477/my/bookmarks/BAh7BkkiC19yYWlscwY6BkVUewdJIglkYXRhBjsAVEkiLmdpZDovL2JjMy9SZWNvcmRpbmcvMTA2OTQ4MDAyND9leHBpcmVzX2luBjsAVEkiCHB1cgY7AFRJIg1yZWFkYWJsZQY7AFQ=--0000000000000000000000000000000000000000.json",
+    "subscription_url": "https://3.basecampapi.com/195539477/buckets/2085958505/recordings/1069480024/subscription.json",
+    "parent": {
+      "id": 1069479830,
+      "title": "Launch",
+      "type": "Todolist",
+      "url": "https://3.basecampapi.com/195539477/buckets/2085958505/todolists/1069479830.json",
+      "app_url": "https://3.basecamp.com/195539477/buckets/2085958505/todolists/1069479830"
+    },
+    "bucket": {
+      "id": 2085958505,
+      "name": "The Leto Laptop",
+      "type": "Project"
+    },
+    "creator": {
+      "id": 1049715929,
+      "attachable_sgid": "BAh7BkkiC19yYWlscwY6BkVUewdJIglkYXRhBjsAVEkiK2dpZDovL2JjMy9QZXJzb24vMTA0OTcxNTkyOT9leHBpcmVzX2luBjsAVEkiCHB1cgY7AFRJIg9hdHRhY2hhYmxlBjsAVA==--0000000000000000000000000000000000000000",
+      "name": "Matt Donahue",
+      "personable_type": "User",
+      "title": "Global Data Strategist",
+      "tagline": null,
+      "location": null,
+      "created_at": "2026-05-28T17:22:27.821Z",
+      "updated_at": "2026-05-28T17:22:27.821Z",
+      "email_address": "matt@honchodesign.com",
+      "bio": null,
+      "admin": false,
+      "owner": false,
+      "client": false,
+      "employee": false,
+      "time_zone": "America/Chicago",
+      "avatar_url": "https://3.basecampapi.com/195539477/people/BAhpBNlkkT4=--0000000000000000000000000000000000000000/avatar",
+      "can_ping": true,
+      "can_manage_projects": true,
+      "can_manage_people": true,
+      "can_access_timesheet": true,
+      "can_access_hill_charts": true
+    }
+  }
+]
+```
+
+###### Copy as cURL
+
+```shell
+curl -s -H "Authorization: Bearer $ACCESS_TOKEN" https://3.basecampapi.com/$ACCOUNT_ID/recordings/2/backlinks.json
+```
+
+Legacy project-scoped routes
+-----------------------------
+
+The following project-scoped routes are still supported and will remain available, but flat routes above are the canonical form for new integrations.
+
+* `GET /buckets/1/recordings/2/backlinks.json` → [Get backlinks](#get-backlinks)
+
+[recordings]: recordings.md#recordings

sections/card_table_cards.md

@@ -35,6 +35,9 @@ Get cards in a column
     "comments_url": "https://3.basecampapi.com/195539477/buckets/2085958505/recordings/1069480041/comments.json",
     "boosts_count": 0,
     "boosts_url": "https://3.basecampapi.com/195539477/buckets/2085958505/recordings/1069480041/boosts.json",
+    "subtasks_count": 1,
+    "subtasks_completed_count": 0,
+    "subtasks_url": "https://3.basecampapi.com/195539477/recordings/1069480041/subtasks.json",
     "position": 1,
     "parent": {
       "id": 1069479834,
@@ -95,7 +98,7 @@ Get cards in a column
         "title": "Find inspiration",
         "inherits_status": true,
         "type": "Kanban::Step",
-        "url": "https://3.basecampapi.com/195539477/buckets/2085958505/card_tables/steps/1069480042.json",
+        "url": "https://3.basecampapi.com/195539477/buckets/2085958505/subtasks/1069480042.json",
         "app_url": "https://3.basecamp.com/195539477/buckets/2085958505/card_tables/cards/1069480041#__recording_1069480042",
         "bookmark_url": "https://3.basecampapi.com/195539477/my/bookmarks/BAh7BkkiC19yYWlscwY6BkVUewdJIglkYXRhBjsAVEkiLmdpZDovL2JjMy9SZWNvcmRpbmcvMTA2OTQ4MDA0Mj9leHBpcmVzX2luBjsAVEkiCHB1cgY7AFRJIg1yZWFkYWJsZQY7AFQ=--ac919964135c88e0b8d853cf2c2968095f8ce46a.json",
         "position": 1,
@@ -167,7 +170,7 @@ Get cards in a column
             "can_access_hill_charts": true
           }
         ],
-        "completion_url": "/195539477/buckets/2085958505/steps/1069480042/completions.json"
+        "completion_url": "https://3.basecampapi.com/195539477/subtasks/1069480042/completion.json"
       }
     ]
   }
@@ -205,6 +208,9 @@ Get a card
   "comments_url": "https://3.basecampapi.com/195539477/buckets/2085958505/recordings/1069480041/comments.json",
   "boosts_count": 0,
   "boosts_url": "https://3.basecampapi.com/195539477/buckets/2085958505/recordings/1069480041/boosts.json",
+  "subtasks_count": 1,
+  "subtasks_completed_count": 0,
+  "subtasks_url": "https://3.basecampapi.com/195539477/recordings/1069480041/subtasks.json",
   "position": 1,
   "parent": {
     "id": 1069479834,
@@ -265,7 +271,7 @@ Get a card
       "title": "Find inspiration",
       "inherits_status": true,
       "type": "Kanban::Step",
-      "url": "https://3.basecampapi.com/195539477/buckets/2085958505/card_tables/steps/1069480042.json",
+      "url": "https://3.basecampapi.com/195539477/buckets/2085958505/subtasks/1069480042.json",
       "app_url": "https://3.basecamp.com/195539477/buckets/2085958505/card_tables/cards/1069480041#__recording_1069480042",
       "bookmark_url": "https://3.basecampapi.com/195539477/my/bookmarks/BAh7BkkiC19yYWlscwY6BkVUewdJIglkYXRhBjsAVEkiLmdpZDovL2JjMy9SZWNvcmRpbmcvMTA2OTQ4MDA0Mj9leHBpcmVzX2luBjsAVEkiCHB1cgY7AFRJIg1yZWFkYWJsZQY7AFQ=--ac919964135c88e0b8d853cf2c2968095f8ce46a.json",
       "position": 1,
@@ -337,7 +343,7 @@ Get a card
           "can_access_hill_charts": true
         }
       ],
-      "completion_url": "/195539477/buckets/2085958505/steps/1069480042/completions.json"
+      "completion_url": "https://3.basecampapi.com/195539477/subtasks/1069480042/completion.json"
     }
   ]
 }

sections/card_table_steps.md

@@ -1,6 +1,12 @@
 Card table steps
 ================
 
+These are the card-scoped endpoints for what are now called [subtasks][subtasks]. They will
+remain available indefinitely, but their paths speak of cards. The
+[subtasks][subtasks] endpoints work on a step under any recording — a to-do included — and are
+the ones to use for new integrations. Both operate on the same records and return the same
+payload.
+
 Available since Basecamp 5: steps are now also reachable via flat top-level paths
 (`/card_tables/steps/:id.json`, `/card_tables/cards/:card_id/steps.json`, …) in addition to the
 historical bucket-scoped paths shown below. Both paths return the same JSON shape and accept the
@@ -19,7 +25,8 @@ Endpoints:
 Get steps in a card
 --------------------
 
-Steps are returned unpaginated as part of the [Get a card][card] endpoint payload.
+The first 100 steps are returned as part of the [Get a card][card] endpoint payload. A card with
+more than that reports the real total in `subtasks_count`; fetch the rest from `subtasks_url`.
 
 Create a step
 -------------------------
@@ -129,7 +136,7 @@ Reposition a step
 **Required parameters**:
 
 * `source_id` – the step id. Step ids can be found via the [Get a card][card] endpoint.
-* `position` – Zero indexed.
+* `position` – the 1-based position to move it to.
 
 This endpoint will return `204 No Content` if successful.
 
@@ -160,3 +167,4 @@ The following project-scoped routes are still supported and will remain availabl
 
 [card]: card_table_cards.md#get-a-card
 [people]: people.md#get-all-people
+[subtasks]: subtasks.md#subtasks