Zimbra

Zimbra is an open-source email and collaboration platform serving more than 200 million users worldwide, offering email, calendar, contacts, tasks, group chat, file storage (Briefcase), and an in-browser office suite. It is deployed self-hosted (on-premises, private cloud, or regional data center) to give organizations full data sovereignty over their communications. Zimbra's programmatic surface is a SOAP API (account, mail, and admin namespaces) wrapped by a first-party GraphQL/JavaScript client (@zimbra/api-client); it also speaks the IMAP, POP3, SMTP, CalDAV, CardDAV, and Exchange ActiveSync standards. There is no public OpenAPI/REST contract. Backed by Redpoint Ventures; added to the API Evangelist network from a VC-portfolio lead and enriched from Zimbra's public developer surface.

Zimbra publishes 1 API on the APIs.io network. Tagged areas include Email, Collaboration, Calendar, Messaging, and Open-Source.

Zimbra’s developer surface includes documentation, API reference, engineering blog, support, signup flow, authentication, and 13 more developer resources.

🌐 Visit website 📡 Source on GitHub

25.3/100 emerging ▬ flat Agent 3/100 human only saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

AccessSelf serve

1 APIs

Email Collaboration Calendar Messaging Open-Source SOAP GraphQL Productivity

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 25.3/100 · emerging

Contract Quality 0.0 / 25

Developer Ergonomics 7.9 / 20

Access Clarity 6.8 / 20

Operational Transparency 1.7 / 13

Contract Governance 2.2 / 12

Discoverability 6.7 / 10

Agent readiness — 3/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/zimbra: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 1

Individual APIs this provider publishes, each with its own machine-readable definition.

Zimbra SOAP API

SOAP API (XML and JSON encodings) for Zimbra Collaboration — account, mail, and admin operations, POSTed to /service/soap on a Zimbra deployment. Self-hosted, so the base host i...

Security Posture 3

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Zimbra Authentication

soap-auth-token/preauth/oauth2 · 4 schemes

SECURITY

Zimbra Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Zimbra Vulnerability Disclosure

disclosure policy published

SECURITY

Resources

Get Started 1

Portal, sign-up, and the first successful call

SignUp

SignUp

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

Design & Contract 3

Pagination, idempotency, versioning, errors, and events

Conventions

Conventions

Lifecycle

Lifecycle

Conformance

Conformance

Build 3

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Packages

Packages

SDKs

SDKs

Access & Security 4

Authentication, authorization, and security posture

Authentication

Authentication

DomainSecurity

DomainSecurity

VulnerabilityDisclosure

VulnerabilityDisclosure

Security

Security

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Source (apis.yml)

aid: zimbra
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: false
  label: Hosted service · you call their endpoint
  confidence: medium
  source:
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: self-serve
  trial: false
  try_now: false
  public: false
  label: Self-serve signup
  confidence: medium
  source:
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/zimbra.png
name: Zimbra
description: Zimbra is an open-source email and collaboration platform serving more than 200 million users worldwide, offering
  email, calendar, contacts, tasks, group chat, file storage (Briefcase), and an in-browser office suite. It is deployed self-hosted
  (on-premises, private cloud, or regional data center) to give organizations full data sovereignty over their communications.
  Zimbra's programmatic surface is a SOAP API (account, mail, and admin namespaces) wrapped by a first-party GraphQL/JavaScript
  client (@zimbra/api-client); it also speaks the IMAP, POP3, SMTP, CalDAV, CardDAV, and Exchange ActiveSync standards. There
  is no public OpenAPI/REST contract. Backed by Redpoint Ventures; added to the API Evangelist network from a VC-portfolio
  lead and enriched from Zimbra's public developer surface.
url: https://raw.githubusercontent.com/api-evangelist/zimbra/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- redpoint-ventures
x-tier: stub
x-tier-reason: portfolio-lead
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-21'
tags:
- Email
- Collaboration
- Calendar
- Messaging
- Open-Source
- SOAP
- GraphQL
- Productivity
tags_raw:
- Email
- Collaboration
- Calendar
- Messaging
- Open Source
- SOAP
- GraphQL
- Productivity
apis:
- name: Zimbra SOAP API
  description: SOAP API (XML and JSON encodings) for Zimbra Collaboration — account, mail, and admin operations, POSTed to
    /service/soap on a Zimbra deployment. Self-hosted, so the base host is per-deployment; the reference documents every request/response.
  humanURL: https://files.zimbra.com/docs/soap_api/
  properties:
  - type: APIReference
    url: https://files.zimbra.com/docs/soap_api/
  - type: Documentation
    url: https://wiki.zimbra.com/wiki/SOAP_API_Reference_Material_Beginning_with_ZCS_8.0
  - type: SDKs
    url: packages/zimbra-packages.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://www.zimbra.com/
- type: Documentation
  url: https://www.zimbra.com/product/zimbra-documentation/
- type: APIReference
  url: https://files.zimbra.com/docs/soap_api/
- type: Blog
  url: https://blog.zimbra.com/
- type: Support
  url: https://support.zimbra.com/
- type: GitHubOrganization
  url: https://github.com/Zimbra
- type: SignUp
  url: https://www.zimbra.com/connect/forms/?form=trial-license
- type: TermsOfService
  url: https://www.zimbra.com/product/licenses-and-terms-of-use/
- type: PrivacyPolicy
  url: https://synacor.com/privacy-policy
- type: Packages
  url: packages/zimbra-packages.yml
- type: SDKs
  url: packages/zimbra-packages.yml
- type: Authentication
  url: authentication/zimbra-authentication.yml
- type: Conventions
  url: conventions/zimbra-conventions.yml
- type: Lifecycle
  url: lifecycle/zimbra-lifecycle.yml
- type: Conformance
  url: conformance/zimbra-conformance.yml
- type: LLMsTxt
  url: llms/zimbra-llms.txt
- type: DomainSecurity
  url: security/zimbra-domain-security.yml
- type: VulnerabilityDisclosure
  url: security/zimbra-vulnerability-disclosure.yml
- type: Security
  url: https://wiki.zimbra.com/wiki/Security_Center
x-enrichment:
  date: '2026-07-21'
  status: enriched
  artifacts_added: 9
  pass: local-v1

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