# Hosts and availability (/docs/scheduling/hosts)

A **host** is someone who can be booked, usually one of your users. Give each your own id as `uid`,
and use it wherever an id goes.

```ts twoslash
import { Coss } from "coss";
const coss = new Coss();
// ---cut---
await coss.scheduling.hosts.create({
  uid: "doctor_482",
  name: "Dr. Ana Reyes",
  time_zone: "America/New_York",
  attributes: { licensed_in: ["NY", "NJ"], language: "es" },
});
```

An `email` is where their notifications go, not an identity: two hosts can share one, and a host
needs none. `attributes` are what [pools](/docs/scheduling/pools-and-groups) choose hosts by.

## Schedules [#schedules]

A schedule is weekly hours in local time, with Sunday as day `0`. A host's first schedule is their
default.

```ts twoslash
import { Coss } from "coss";
const coss = new Coss();
// ---cut---
await coss.scheduling.schedules.create("doctor_482", {
  rules: [
    { days: [1, 2, 3, 4], start: "09:00", end: "17:00" },
    { days: [5], start: "09:00", end: "12:00" },
  ],
  overrides: [
    { date: "2027-12-24", ranges: [] },
    { date: "2027-12-31", ranges: [{ start: "09:00", end: "11:00" }] },
  ],
});
```

An override replaces that whole day: no ranges means unavailable. Hours stay put across daylight
saving, so 09:00 is 09:00 on both sides of a clock change. A range can't cross midnight: use two, and
`24:00` for the end of a day.

Changing a schedule only changes what's offered next. Existing bookings stay.

## Hosts leaving [#hosts-leaving]

A `disabled` host keeps their bookings but isn't offered. A host with bookings still to come can't be
deleted (`host_has_live_bookings`): cancel them or disable the host.