> ## Documentation Index
> Fetch the complete documentation index at: https://signatureapi-daf4ee54.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Envelope topics

> Organize envelopes with tags and filter webhook notifications by topic

Topics are tags you assign to envelopes. They serve two purposes: filtering webhook notifications and querying envelopes by category.

You can assign up to 10 topics per envelope. Each topic must start with a lowercase letter and contain only lowercase letters, numbers, and underscores (maximum 32 characters).

## Assigning topics

Set the `topics` property when creating an envelope:

```json theme={null}
// POST https://api.signatureapi.com/v1/envelopes
// X-API-Key: key_test_...
// Content-Type: application/json

{
  "title": "Sales Contract",
  "topics": ["sales", "q1_2026"],
  "documents": [
    //...
  ],
  "recipients": [
    //...
  ]
}
```

## Filtering webhooks by topic

Configure a webhook endpoint in the dashboard to receive events only for envelopes with specific topics. This lets you route different envelope types to different endpoints or trigger different workflows without building complex routing logic.

For example, a company with separate finance and sales workflows can:

1. Tag finance envelopes with `finance` and sales envelopes with `sales`.
2. Configure one webhook endpoint to receive only `finance` events and another for `sales` events.
3. Each endpoint receives only the notifications relevant to its workflow.

A webhook with no topic filter receives events for all envelopes.

## Filtering envelopes by topic

Use the `topic` query parameter on the [List Envelopes](/docs/api/resources/envelopes/list) endpoint to retrieve envelopes for a specific topic:

```json theme={null}
// GET https://api.signatureapi.com/v1/envelopes?topic=sales
// X-API-Key: key_test_...
```

## Topics vs. metadata

Use topics to categorize and filter envelopes within SignatureAPI. Use [metadata](/docs/api/resources/envelopes/metadata) to store information that connects envelopes to records in your own systems.