AtomicJar

AtomicJar is a developer-testing company, founded in 2021 by the original creators and maintainers of the open-source Testcontainers project and acquired by Docker in December 2023. AtomicJar builds tooling that lets developers run reliable integration tests against real service dependencies (databases, message brokers, and other systems) defined in code and wrapped in Docker containers, replacing brittle mocks and in-memory fakes. Its product line spans Testcontainers OSS (the open-source libraries for Java, .NET, Go, Node.js, Python, Rust, and more), Testcontainers Desktop (a companion app for local development), and Testcontainers Cloud (a hosted service that offloads container execution to the cloud so tests run consistently from a laptop through CI without a local Docker daemon). AtomicJar and its Testcontainers products are used by engineering teams at companies including Spotify, Uber, Capital One, Elastic, Netflix, and Zalando.

AtomicJar is profiled on the APIs.io network. Tagged areas include Company, Devops, Testing, Integration Testing, and Testcontainers.

AtomicJar’s developer surface includes documentation, getting-started guide, engineering blog, pricing, signup flow, support, and 6 more developer resources.

🌐 Visit website 📡 Source on GitHub

21.2/100 emerging ▬ flat Agent 0/100 human only Full breakdown ↓
scored 2026-07-28 · rubric v0.5

0 APIs

CompanyDevopsTestingIntegration TestingTestcontainersContainersDeveloper ToolsContinuous IntegrationOpen Source

Kin Score

Kin Score How this is scored →
scored 2026-07-28 · rubric v0.5

Composite quality — 21.2/100 · emerging

Contract Quality 0.0 / 25

Developer Ergonomics 7.0 / 20

Commercial Clarity 6.8 / 20

Operational Transparency 0.7 / 13

Governance 0.0 / 12

Discoverability 6.8 / 10

Agent readiness — 0/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 15

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

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/atomicjar: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

SignUp

SignUp

Login

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 2

Pricing, plans, and the legal terms of use

Pricing

Pricing

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Source (apis.yml)

aid: atomicjar
name: AtomicJar
description: AtomicJar is a developer-testing company, founded in 2021 by the original creators and maintainers of the open-source
  Testcontainers project and acquired by Docker in December 2023. AtomicJar builds tooling that lets developers run reliable
  integration tests against real service dependencies (databases, message brokers, and other systems) defined in code and
  wrapped in Docker containers, replacing brittle mocks and in-memory fakes. Its product line spans Testcontainers OSS (the
  open-source libraries for Java, .NET, Go, Node.js, Python, Rust, and more), Testcontainers Desktop (a companion app for
  local development), and Testcontainers Cloud (a hosted service that offloads container execution to the cloud so tests run
  consistently from a laptop through CI without a local Docker daemon). AtomicJar and its Testcontainers products are used
  by engineering teams at companies including Spotify, Uber, Capital One, Elastic, Netflix, and Zalando.
url: https://raw.githubusercontent.com/api-evangelist/atomicjar/refs/heads/main/apis.yml
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://www.atomicjar.com/wp-content/uploads/2022/08/aj-featured-image.png
x-type: company
x-source: vc-portfolio
x-backed-by:
- insight-partners
x-tier: stub
x-tier-reason: portfolio-lead
x-status: acquired-by-docker-2023-12
specificationVersion: '0.20'
created: '2026-07-17'
modified: '2026-07-18'
tags:
- Company
- Devops
- Testing
- Integration Testing
- Testcontainers
- Containers
- Developer Tools
- Continuous Integration
- Open Source
apis: []
common:
- type: DomainSecurity
  url: security/atomicjar-domain-security.yml
- type: Website
  url: https://www.atomicjar.com/
- type: DeveloperPortal
  url: https://testcontainers.com/
- type: Documentation
  url: https://testcontainers.com/cloud/docs/
- type: GettingStarted
  url: https://testcontainers.com/getting-started/
- type: Blog
  url: https://www.atomicjar.com/blog/
- type: GitHubOrganization
  url: https://github.com/AtomicJar
- type: Pricing
  url: https://testcontainers.com/cloud/pricing/
- type: SignUp
  url: https://app.testcontainers.cloud/signup
- type: Login
  url: https://app.testcontainers.cloud/login
- type: Support
  url: https://slack.testcontainers.org/
- type: PrivacyPolicy
  url: https://www.atomicjar.com/privacy-policy/
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