Built for pytest · v1.0 MVP Live

Don't run all tests.
Run the right ones.

Smart test runner for Pytest that dynamically maps and runs only tests relevant to your changes.

Get Started Free View Documentation
bash — delta
$ git commit -m "my changes"
Mapping Service: Delta Cloud (repo aa251edf...)
Test discovery stats:
   Total tests found: 10350
   Already mapped: 10080
   Unmapped (need to run): 270
   Affected (need to run): 67
# Running 337 tests out of 10350
# Saved: 96.7%

Built for High-Velocity Teams

Stop waiting for CI. Start shipping with confidence.

Intelligent Selection

Focus strictly on your deltas. Analyze git changes to select and run only the exact subset of affected tests, avoiding redundant runs.

Cloud Mapping

Sync test coverage across your team. Mappings are shared and computed in the cloud, aligning developer environments instantly.

Instant Feedback

Cut developer wait times from minutes to seconds with instant test execution.

AI Token Savings

Prevent AI agents from guessing the test scope. Delta serves the exact affected tests, saving millions of context tokens in AI-driven workflows.

Simple, Predictable Pricing

Choose the plan that fits your engineering velocity. No hidden fees.

Monthly
Annual Save 17%
Open Source Free

Community Free

Perfect for solo developers and public open-source repos.

$0/mo
Free Forever
  • 500 tests / private repo
  • 1 private repository
  • Unlimited public OSS repos
  • Priority Cloud Runner
Get Started Free
Most Popular

Developer Pro

For fast-moving startups and professional developers.

$99/mo
Billed monthly
  • 10,000 tests / repo
  • 5 repositories
  • Priority Cloud Runner
  • Dedicated Support
Start Pro Trial

Engineering Team

For growing engineering teams scaling their CI/CD pipelines.

$499/mo
Billed monthly
  • 100,000 tests / repo
  • 25 repositories
  • Priority Cloud Runner
  • Dedicated Support
Start Team Trial

Enterprise

Custom limits, dedicated infrastructure, and enterprise SLAs.

Custom
Annual billing
  • Unlimited mapped tests
  • Unlimited repositories
  • Dedicated Cloud Runner
  • 24/7 Dedicated Support & SLA
  • Custom SAML / SSO
Contact Sales

Building public open-source?

DeltaTest is committed to supporting open-source software. All public repositories get unlimited test allocations, mapping syncs, and execution histories for free.

Claim Free OSS Access →

Quick Start in 60 Seconds

  • 1
    Install CLI pip install pytest-deltatest
  • 2
    Login & Track delta login
    delta track --name my-app
  • 3
    Build & Push Mapping delta build-mapping
    delta push
  • 4
    Run Affected Tests delta run

    Intelligently runs only the tests affected by your code changes.

json 
# Example query result from API
{
  "affected_tests": [
    "test_auth.py::test_login",
    "test_auth.py::test_logout"
  ],
  "stats": {
    "query_ms": 12,
    "coverage_pct": 84.5
  }
}
VS Code Extension

Delta lives inside your editor

Every line covered by a test glows. Hover to see which test covers it. Click to run only the affected tests — without leaving VS Code.

Visual Studio Code — Python DeltaTest
Free · Open Source · VS Marketplace
Inline Coverage Glow
Every line executed by a test is highlighted with a purple glow. Untouched lines stay dark — at a glance.
Hover Tooltips
Hover any covered line and see the exact test IDs that execute it. No guessing which test covers what.
Auto-Run on Save
Save a file and the affected tests run automatically — results go straight into the VS Code Test Results panel.
One-Click Mapping Sync
Update Mapping button runs delta build-mapping and delta push in a terminal. No CLI needed.
Install from VS Marketplace Extension docs
Python only · pytest required