6 Wunderkinder

6 Wunderkinder (6Wunderkinder GmbH) was a Berlin-based software startup founded in 2010 that built Wunderlist, a popular cross-platform to-do list and task management application. The company shipped a public REST API for Wunderlist in 2013, along with webhooks and integrations such as Slack and Sunrise, and rebuilt its backend into roughly 60 microservices behind a single unified API. Backed by Earlybird and Sequoia Capital, 6 Wunderkinder was acquired by Microsoft in June 2015 for a reported US$100-200M. Microsoft folded the product into Microsoft To Do and discontinued Wunderlist on 6 May 2020. This profile is retained as a historical record; the company is defunct and publishes no live API, developer portal, or documentation.

6 Wunderkinder is profiled on the APIs.io network. Tagged areas include Company, Productivity, Task Management, To-Do, and Berlin.

🌐 Visit website 📡 Source on GitHub

5.0/100 minimal ▬ flat Agent 0/100 human only Full breakdown ↓
scored 2026-08-21 · rubric v0.12.0

0 APIs

Company Productivity Task Management To-Do Berlin Germany Defunct Acquired

Kin Score

Kin Score How this is scored →
scored 2026-08-21 · rubric v0.12.0

Composite quality — 5.0/100 · minimal

Contract Quality 0.0 / 25

Developer Ergonomics 0.0 / 20

Access Clarity 0.0 / 20

Operational Transparency 0.0 / 13

Contract Governance 0.0 / 12

Discoverability 5.0 / 10

Agent readiness — 0/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 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

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/6-wunderkinder: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

Source (apis.yml)

aid: 6-wunderkinder
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source: []
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/6-wunderkinder.png
name: 6 Wunderkinder
description: 6 Wunderkinder (6Wunderkinder GmbH) was a Berlin-based software startup founded in 2010 that built Wunderlist,
  a popular cross-platform to-do list and task management application. The company shipped a public REST API for Wunderlist
  in 2013, along with webhooks and integrations such as Slack and Sunrise, and rebuilt its backend into roughly 60 microservices
  behind a single unified API. Backed by Earlybird and Sequoia Capital, 6 Wunderkinder was acquired by Microsoft in June 2015
  for a reported US$100-200M. Microsoft folded the product into Microsoft To Do and discontinued Wunderlist on 6 May 2020.
  This profile is retained as a historical record; the company is defunct and publishes no live API, developer portal, or
  documentation.
url: https://raw.githubusercontent.com/api-evangelist/6-wunderkinder/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- earlybird
x-tier: stub
x-tier-reason: portfolio-lead
x-status: defunct
x-status-detail: Acquired by Microsoft June 2015; Wunderlist discontinued 6 May 2020; all domains (6wunderkinder.com, wunderlist.com,
  developer.wunderlist.com) return no response (HTTP 000).
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-17'
tags:
- Company
- Productivity
- Task Management
- To-Do
- Berlin
- Germany
- Defunct
- Acquired
apis: []
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence

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