> For the complete documentation index, see [llms.txt](https://docs.zero.inc/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.zero.inc/developers/api.md).

# API

When you need Zero in your own code — a sync job, an internal tool, a script that runs nightly — the REST API reads and writes workspace data over HTTPS at `https://api.zero.inc`: companies, contacts, deals, notes, tasks, pipelines, lists, custom properties, sequences and the rest. Every request carries a Bearer token and is scoped to the workspaces that token can reach. It is the same API Zero's own agents run on.

{% hint style="info" %}
The Zero API is currently in beta. Contact the Zero team to request access.
{% endhint %}

Create a key in **Settings → Connections → API keys**: under **Personal API keys**, **Generate API key**, give it a name and an expiry, and copy it there and then — it is not shown again. The same page has your **Workspace ID**, which most requests take as `workspaceId`.

## Pages in this section

| Page                                                  | Use it for                                                                                                                                                   |
| ----------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| [Introduction](/developers/api/introduction.md)       | Base URL, authentication, the `fields` / `where` / `orderBy` / `limit` / `offset` query parameters, response format, and deleting vs. archiving. Start here. |
| [Merging Records](/developers/api/merging-records.md) | `POST /api/{contacts\|companies\|deals}/merge` — fold duplicate records into one primary record and repoint their related data.                              |
| **API Reference**                                     | The OpenAPI reference that follows these pages in the navigation: every endpoint, parameter, and schema, with a downloadable spec.                           |

## What the API covers

* **Core records** — Workspaces, Companies, Contacts, Deals
* **Activity** — Notes, Tasks, Custom Activities, Custom Activity Types, Files (multipart upload via `POST /api/files/upload`), Meetings (read-only: calendar events and transcripts)
* **Sales structure** — Pipelines, Pipeline Stages, Lists, Views, Columns (custom property definitions)
* **Pricing** — Products (the workspace product catalog and its price variants) and Quotes (line items, contract term, and totals)
* **Outreach** — Sequences, Sequence Enrollments
* **People and access** — Users and Memberships (read-only)

Most resources follow the same shape: `GET /api/{resource}`, `GET /api/{resource}/{id}`, `POST`, `PATCH`, `DELETE`. Not all of them support every operation — meetings, transcripts, users and memberships are read-only, and files are uploaded through `POST /api/files/upload` rather than a generic `POST`. The API Reference below lists the exact operations for each resource. One thing to do early — read the `Columns` endpoints, because custom properties are addressed by column ID, and you will need them to filter or update custom fields.

## API or MCP?

Both reach the same data, so the question is what the caller is. [MCP](/developers/mcp.md) presents Zero as a set of tools an AI assistant can use conversationally, with no request code to write. The REST API is for when you want explicit control over queries, field selection, pagination and writes.


---

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