Handshake

Stop shipping
breaking changes.

Catch API drift before production. Upload your spec, get instant mock servers, and validate every PR automatically.

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Trusted by engineering teams

AcmeTechFlowNebulaQuantumApexVertex

Features

Everything you need to shipwith confidence

Contract Versioning

Track every API change with automatic diff detection. Breaking changes are flagged instantly.

User API v2.1.0 → v2.2.0
-"role": { "type": "string" }
+"role": { "type": "string", "enum": ["admin", "user"] }
1 breaking change detected

Mock Servers

Generate realistic mock APIs from your contracts — hosted in the cloud or on your local machine with our CLI.

$ curl acme.mock.handshake.dev/users/1
{
"id": 1,
"name": "Jane Cooper",
"email": "jane@acme.co"
}
200 OK · 12ms · AI-enhanced data

CI Validation

Five lines of YAML. Every pull request validated against your contract. Breaking changes blocked before merge.

PR #142 — Update user endpoints
GET /users — 200 OK (45ms)
POST /users — 201 Created (89ms)
DELETE /users/:id — 404 Not Found
2 passed · 1 failed · blocked merge

Consumer Alerts & Approvals

Breaking changes trigger approval flows. Affected consumers review and approve before anything ships.

Breaking change detected

Field "role" removed from User schema

Review requested from @frontend-team

2 consumer apps affected

Approved

Safe to deploy

AI-Enhanced Mock Data

Claude generates realistic mock data for fields that faker.js can't handle — stock tickers, bios, dietary restrictions. Templates generated once per schema change, cached forever.

Before (faker.js)
"companyTicker": "a8xK2mP9qR"
After (AI-enhanced)
"companyTicker": "AAPL"

Local Mock Server

Run mock servers on your machine with a single command. No Docker, no cloud dependency. Your contracts, served locally with realistic data.

Offline supportCustom responsesWatch mode
# Install and start in seconds
npx @handshake/cli mock start
# Make requests against your mock
curl http://localhost:4010/api/users
{
"id": "a1b2c3",
"name": "John Smith",
"email": "john@example.com"
}

Pricing

Simple, transparent pricing

Start free. Scale when you're ready. Billed per Hub (your company workspace), not per seat.

Free

For individual developers exploring API contracts.

$0/mo

per Hub

  • 2 projects
  • 3 contracts
  • 100 CI runs/month
  • 1 team member
  • Mock servers
  • Local mock server CLI
  • In-app & email alerts
Get Started

Pro

For small teams shipping APIs regularly.

$29/mo

per Hub

  • 10 projects
  • 25 contracts
  • 1,000 CI runs/month
  • 5 team members
  • Mock servers
  • Local mock server CLI
  • AI inference
  • Slack & webhook alerts
Get Started

Recommended

Team

For engineering orgs that need full control.

$99/mo

per Hub

  • Unlimited projects
  • Unlimited contracts
  • 10,000 CI runs/month
  • Unlimited members
  • Local mock server CLI
  • Approval workflows
  • Consumer registry
  • All notification channels
Get Started

Enterprise

For Hubs with specific requirements.

Custom
  • Everything in Team
  • Local mock server CLI
  • Custom CI limits
  • SSO & SAML
  • Dedicated support
  • SLA guarantee
  • On-prem option
Contact Us

Stop breaking your APIs.

Join engineering teams using Handshake to ship faster without the fear of silent contract drift.

Get Started Free

Free forever · Setup in 5 minutes