---
title: "Create a signature"
method: POST
path: "/v3/grants/{grant_id}/signatures"
tags: ["Signatures"]
---

# Create a signature

`POST /v3/grants/{grant_id}/signatures`

Create a signature for a grant. Each grant can have up to 10 signatures.

Nylas sanitizes the HTML content on input to prevent malicious content. Images must use
externally hosted URLs (base64 inline images are not supported). Maximum signature size is 100 KB.

## Query parameters

- `select` string

## Request body

- object
  - `name` string, required — A label for the signature (for example, "Work", "Personal", or "Mobile").
  - `body` string, required — The HTML content of the signature. Maximum 100 KB. Images must use externally hosted URLs (base64 inline images are not supported). Nylas sanitizes the HTML on input to prevent malicious content.

## Response `201`

Signature

- object
  - `request_id` string — The request ID.
  - `data` object — The response object.
    - `id` string — Globally unique identifier for the signature.
    - `grant_id` string — The ID of grant for the connected user.
    - `name` string — A label for the signature (for example, "Work", "Personal", or "Mobile").
    - `body` string — The HTML content of the signature. Images must use externally hosted URLs.
    - `object` string — The type of object.
    - `created_at` integer — Unix timestamp when the signature was created.
    - `updated_at` integer — Unix timestamp when the signature was last modified.

## Other responses

- `400` — Bad Request
- `401` — Unauthorized
- `429` — Rate Limit
- `504` — Provider Failure

---

[API](https://skmtc.dev/nylas/apis/nylas-api.md) · [All operations](https://skmtc.dev/nylas/apis/nylas-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/nylas/nylas-api/revisions/51c2c1b4ecff/schema)