IDs & Object Types

Every resource in the API has a prefixed string ID and an object field that tells you its type.

ID format

IDs are opaque strings with a type prefix:

Resource	Prefix	Example
Account	`act_`	`act_k8x2m`
Item	`itm_`	`itm_r9f3a`
Annotation	`ann_`	`ann_m2k8v`
Tag	`tag_`	`tag_n5j2x`
Author	`aut_`	`aut_p4w7q`
Reading Session	`rs_`	`rs_k8x2m`

The prefix tells you the resource type at a glance, which is helpful when debugging or reading logs.

Object types

Every response includes an object field identifying the resource type:

{
  "object": "item",
  "id": "itm_r9f3a",
  "title": "How to Do Great Work"
}

For lists:

{
  "object": "list",
  "results": [
    { "object": "item", "id": "itm_r9f3a" },
    { "object": "item", "id": "itm_x7k2p" }
  ],
  "has_more": false,
  "next_cursor": null
}

This makes it safe to handle polymorphic responses — you can always check object to know what you’re looking at.

Timestamps

All timestamps are ISO 8601 strings in UTC:

2026-03-30T18:30:00Z

Use these fields for sync, sorting, and display. See incremental sync for how to use updated_at to efficiently stay in sync.

Getting Started

Concepts

API Reference

ID format

Object types

Timestamps

​ID format

​Object types

​Timestamps

ID format

Object types

Timestamps