> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vumasign.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> Everything your own software needs to talk to Vumasign.

Get a credential on [API keys](https://app.vumasign.com/settings/api-keys), point it at the base URL
below, and every endpoint is described in full in the [API reference](/api-reference/list-templates).

## The basics

| | |
| - | - |
| Base URL | `https://app.vumasign.com/api/v1` |
| Authentication | `Authorization: Bearer vsk_live_…` |
| OpenAPI document | [`https://app.vumasign.com/api/v1/openapi.json`](https://app.vumasign.com/api/v1/openapi.json), public, no key needed |
| Documents | PDF or Word, up to 200 pages, and about 6 MB through the API |

**Authentication** is one header, one step. The prefix is stored in clear so a leaked key is
greppable and traceable to an organisation; the secret is stored only as a hash, so nobody —
including us — can recover it. See [Authentication](/authentication).

**The OpenAPI document** is public, needs no key, is readable cross-origin from a browser, and is
generated from the running code — so it cannot describe an endpoint the API does not serve. The
reference on this site is rendered from it. Generate a client from it.

**Documents** are checked by the bytes, not the extension, so renaming a file changes nothing
either way. A Word `.docx` is converted to PDF on our side, and the converted PDF is what fields
are placed on and what gets signed — your original is kept unchanged. Text tags survive that
render. The older `.doc` format is not accepted. Through the API a document travels
base64-encoded inside the JSON body, which is what sets the API's ceiling in the table above,
whatever the document's format or page count; the upload screen, which sends the file itself,
allows more.

## Before the first call

What the reference assumes you already know, and worth reading before the first call: each is a
mistake that is cheap to avoid and expensive to make after a document has been sent.

* [Roles and recipients](/concepts/roles-and-recipients)
* [Getting fields onto a page](/concepts/placing-fields)
* [Text tags](/concepts/text-tags)
* [Field detection](/concepts/field-detection)
* [Test keys and live keys](/concepts/test-and-live)
* [Sealing](/concepts/sealing)