---
title: Events and Channels
description: How events are organized into Channels within a Project, and how long they're kept.
sidebar:
  order: 1
---

An event records something that happened in your application. Every event
belongs to a Project and a Channel: the API key supplies the Project, and
`channelName` supplies the Channel.

Channel names are normalized: lowercased, with spaces and underscores turned
into hyphens and other punctuation removed, up to 100 characters. A Channel is
created by the first event that names it and takes that event's icon and
description. Sending an event to the name of a deleted Channel brings the
Channel back.

A stored event is limited to 16 KB across its fields, including metadata.
Events are kept for 90 days.

## Metadata

`metadata` takes any JSON object. The dashboard shows it when you open an
event, formatting values by their shape and name:

| You send | The dashboard shows |
| --- | --- |
| `"amount": 49, "currency": "EUR"` at the top level | The event's value, **€49**, on the event and in Revenue |
| `{ "amount": 19, "currency": "EUR" }` nested under a key | **€19** as a detail, not counted as revenue |
| A key ending in `Ms`, such as `"durationMs": 1500` | A duration, **2s** |
| A key ending in `Bytes` | A size, such as **4.2 GB** |
| A key ending in `Rate`, with a value from 0 to 1 | A percentage |
| A key ending in `At`, with an ISO 8601 timestamp | A date and time |
| `"rating"` from 1 to 5 | Stars |
| A URL starting with `http://` or `https://` | A link |
| `true` / `false`, lists, nested objects | Yes/No, chips, an indented group |

For an event's value, `amount` must be a JSON number in major units (`49.5`
is €49.50; use a negative amount for a refund) and `currency` a three-letter
ISO 4217 code in any case. Revenue in the dashboard adds up the currency your
events use most; amounts in other currencies still show on their events.