Local-first • Fast • CI-friendly

Catch API contract drift from real traffic.

Validate OpenAPI specs against HAR, curl logs, or normalized JSON. Get grouped errors, fix hints, and an HTML report — without platform lock-in.

Download View Demo Flow
Install
Download contract-tester.exe from GitHub Releases
Run
contract-tester validate --spec api.yaml --traffic traffic.har

How it works

1. Ingest traffic

Load HAR exports, curl logs, or normalized JSON.

2. Validate contracts

Match paths, validate request params and response schemas.

3. Fix faster

Get grouped errors with fix hints and a clean HTML report.

CLI Example
contract-tester validate --spec api.yaml --traffic traffic.har --report

Total checks: 482
Errors: 6

Top error groups:
- response.schema_mismatch|GET|/users/{id}|200 (3)
- request.param.missing|POST|/users (2)

Pricing

Simple, transparent plans. Annual billing gets 2 months free.

Free (Demo)
$0
Great for evaluation.
  • Up to 25 traffic entries
  • Specs up to 30 paths
  • HTML report + fix hints
Pro
$15/user/month
For individuals and small teams.
  • Unlimited traffic and spec size
  • JSON + HTML reports
  • Full request and response validation
Team
$79/team/month
Up to 10 users.
  • Everything in Pro
  • Team license key
  • Priority support

Ship safer APIs, faster.

Start with the demo, upgrade when you are ready.

Download