workflowstacks
devtools

Faster APIs with Specmatic

Ship APIs faster with Specmatic's AI-powered suite.
intermediate⏱ 30 minutes💵 Free (self-hosted)
393 stars65 forksKotlinGuide quality 8/10Updated 8/14/2026100% free · open source
What it is

Use Specmatic to write API code automatically from a specification without needing to write any code.

Real use case example

"A founder of a small startup, Maria, wants to add user management to her website. She writes a specification for creating a new user in her language of choice, and Specmatic instantly generates the API code. She then tests and integrates it into her website, all without any manual coding."

Best insideClaude DesktopCursor
When to use it
  • •When building microservices and APIs that require rapid development and testing
  • •When integrating with third-party APIs and needing to ensure contract compliance
  • •When teams want to reduce API integration surprises and improve overall development speed
Ready-to-paste prompt
Transform a sample specification file into an executable contract using the command `specmatic contract generate --spec src/test/resources/petstore.yaml`
Heads up: Ensure you have Java 11 or later installed on your system, as Specmatic is built using Kotlin and requires a compatible Java runtime environment
Saves to your device
Use with Claude
New

Skip the builder — one click puts this in Claude, Cursor, Antigravity and more.

🛠️ Technical setup

Expect 20–40 minutes in a terminal — or let your AI agent drive it.

Try it instantly — no install
Claude Code
mkdir -p ~/.claude/skills/specmatic && curl -fsSL https://workflowstacks.com/api/skills/specmatic/claude-skill -o ~/.claude/skills/specmatic/SKILL.md
Open in another AI app

Opens the app with this repo with the prompt ready to go — no copy-paste needed.

Connect the whole catalog (MCP)
claude mcp add --transport http workflowstacks https://workflowstacks.com/api/mcp

Adds a WorkflowStacks connector to Claude Code: search and load any skill here by chatting.

How Faster APIs with Specmatic works
Codeflow
Free to inspect

Faster APIs with Specmatic is a very large Kotlin project (~80k lines across 603 code files, plus 464 test files). It is a full software project: use it through its install path rather than reading it end to end. Last commit this month, MIT license, has a test suite.

Size
Very large codebase
~80k lines · 603 code files · days to read — use, don't read
Setup
Developer setup
A real software project. Use it via its install path; don't expect to read it all.
Runs on
Java/JVM
No API keys detected
Kotlin 100%
Where to start reading
  1. 1
    README.md
    Start here — what it does and how to install it
  2. 2
    AGENTS.md
    The instructions the AI actually follows
  3. 3
    core/build.gradle.kts
    Inside core/ — the main logic begins here
What's in each folder
core/Core code — the actual logic1902 files
conformance-tests/Folder251 files
application/Folder111 files
junit5-support/Folder50 files
specmatic-mcp/Folder21 files
gradle/Folder2 files
META-INF/Folder1 files
jmx/Folder1 files
READMEHas testsDocumentedCI checksMIT licenseUpdated this month
Quick Actions
Details
Creator
specmatic
Language
Kotlin
Category
devtools
Published
3/16/2020

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