# Zendesk Sell (Sales CRM) API

> Zendesk Sell (formerly Base CRM) is a sales CRM. Its REST API at https://api.getbase.com
> gives OAuth 2.0-authenticated CRUD access to leads, contacts, deals, notes, tasks, calls
> and custom fields, alongside a Sync API, a polled Firehose change stream and a Search API.
> IMPORTANT FOR AGENTS: Zendesk announced on 2025-09-09 that Zendesk Sell is retired on
> 2027-08-31, after which the product and its data are removed. Do not plan new long-lived
> integrations against this API.

Generated by API Evangelist from https://github.com/api-evangelist/zendesk-sell.
Zendesk publishes no llms.txt on its developer host (developer.zendesk.com/llms.txt -> 404).
A corporate marketing index does exist at https://www.zendesk.com/llms.txt (HTTP 200) but it
indexes zendesk.com content, not the Sell developer surface.

## Facts

- Base URL: https://api.getbase.com
- Version in path: https://api.getbase.com/{api-version}/{resource} — v2 core, v3 Firehose
- Auth: OAuth 2.0 bearer token; scopes read, write, profile
- Rate limit: 36,000 requests/hour per token (10 req/token/second); 429 on exhaustion; no rate-limit headers
- Required header: User-Agent (a request without one is rejected 400 invalid_user_agent)
- Pagination: page (1-based) + per_page (default 25, max 100)
- Errors: {"errors":[{"error":{code,message,details,resource,field}}],"meta":{http_status,logref}}
- Idempotency: none published; upsert endpoints match on business attributes instead
- Events: pull only — Firehose https://api.getbase.com/v3/:resource/stream. No webhooks.

## APIs

- [Zendesk Sell (Sales CRM) API](https://developer.zendesk.com/api-reference/sales-crm/introduction/): Core CRUD over leads, contacts, deals and the rest of the CRM graph.
- [Sync API](https://developer.zendesk.com/api-reference/sales-crm/sync/introduction): Stateful synchronization layer for keeping a local copy current. Premium.
- [Firehose API](https://developer.zendesk.com/api-reference/sales-crm/firehose/overview): Client-pulled change stream, 22 resources, 72-hour retention.
- [Search API](https://developer.zendesk.com/api-reference/sales-crm/search/introduction): Complex filters, sorts and aggregations over leads, contacts and deals.

## Specs

- [Contacts OpenAPI](https://raw.githubusercontent.com/api-evangelist/zendesk-sell/refs/heads/main/openapi/zendesk-sell-contacts-api-openapi.yml)
- [Deals OpenAPI](https://raw.githubusercontent.com/api-evangelist/zendesk-sell/refs/heads/main/openapi/zendesk-sell-deals-api-openapi.yml)
- [Leads OpenAPI](https://raw.githubusercontent.com/api-evangelist/zendesk-sell/refs/heads/main/openapi/zendesk-sell-leads-api-openapi.yml)
- [Postman collection](https://raw.githubusercontent.com/api-evangelist/zendesk-sell/refs/heads/main/collections/zendesk-sell.postman_collection.json)

## Runtime semantics

- [Conventions](https://raw.githubusercontent.com/api-evangelist/zendesk-sell/refs/heads/main/conventions/zendesk-sell-conventions.yml)
- [Error catalog](https://raw.githubusercontent.com/api-evangelist/zendesk-sell/refs/heads/main/errors/zendesk-sell-problem-types.yml)
- [Rate limits](https://raw.githubusercontent.com/api-evangelist/zendesk-sell/refs/heads/main/rate-limits/zendesk-sell-rate-limits.yml)
- [Authentication](https://raw.githubusercontent.com/api-evangelist/zendesk-sell/refs/heads/main/authentication/zendesk-sell-authentication.yml)
- [OAuth scopes](https://raw.githubusercontent.com/api-evangelist/zendesk-sell/refs/heads/main/scopes/zendesk-sell-scopes.yml)
- [Lifecycle and retirement](https://raw.githubusercontent.com/api-evangelist/zendesk-sell/refs/heads/main/lifecycle/zendesk-sell-lifecycle.yml)
- [Event surface](https://raw.githubusercontent.com/api-evangelist/zendesk-sell/refs/heads/main/events/zendesk-sell-events.yml)
- [Data model](https://raw.githubusercontent.com/api-evangelist/zendesk-sell/refs/heads/main/data-model/zendesk-sell-data-model.yml)

## Docs

- [Developer portal](https://developer.zendesk.com/)
- [Sell documentation](https://developer.zendesk.com/documentation/sales-crm/)
- [Making your first call](https://developer.zendesk.com/documentation/sales-crm/first-call/)
- [Authentication](https://developer.zendesk.com/api-reference/sales-crm/authentication/introduction/)
- [Requests and responses](https://developer.zendesk.com/api-reference/sales-crm/requests/)
- [Errors](https://developer.zendesk.com/api-reference/sales-crm/errors/)
- [Pricing and rate limits](https://developer.zendesk.com/api-reference/sales-crm/rate-limits/)
- [Retirement announcement](https://support.zendesk.com/hc/en-us/articles/9591462550042-Announcing-the-retiring-of-Zendesk-Sell)

## SDKs

- [basecrm (Ruby)](https://rubygems.org/gems/basecrm) — 2.0.0, 2021-10-27
- [basecrm (Python)](https://pypi.org/project/basecrm/) — 1.2.9, 2020-05-13
- [basecrm-php](https://packagist.org/packages/basecrm/basecrm-php) — v1.4.4, 2021-06-29
- [basecrm-java](https://central.sonatype.com/artifact/com.getbase/basecrm-java) — 1.5.1, 2021-04-19
- [ZCLI](https://github.com/zendesk/zcli) — 1.1.4, 2026-07-20 (apps/themes tooling, not an API client)

## Status and security

- [Status page](https://status.zendesk.com/)
- [Trust center](https://www.zendesk.com/trust-center/)
- [Responsible disclosure](https://www.zendesk.com/company/policies-and-guidelines/responsible-disclosure-policy/)
- [security.txt](https://www.zendesk.com/.well-known/security.txt)