CodeShift
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Powered by Claude Opus — the most capable code model

Turn legacy code into
modern, shippable apps.

Upload your old codebase. CodeShift analyzes it, plans the migration, rewrites it into a modern stack, tests it, and hands you back a working application — in hours, not months.

First migration on us · No credit card required

codeshift analyze ./legacy-shop.zip

✓ Detected: PHP 5.6 + jQuery 1.9 · 84 files

⚠ 11 outdated deps · 3 SQL-injection risks flagged

Recommended path: PHP to Laravel 11 + React

codeshift migrate --design modern-saas

⠿ Rewriting controllers/CheckoutController.php as app/Http/Controllers…

The workflow

From scary to shippable in four moves

No manual rewrite. No month-long project. Upload, review, deploy.

1

Analyze

CodeShift scans the whole repo, detects the framework and version, maps dependencies, and flags risks before touching a line.

2

Plan

It proposes a dependency-aware migration plan and the ideal target stack — scaffolding, data layer, logic, UI, tests.

3

Rewrite

The engine restructures your code into modern, idiomatic architecture — not a line-by-line port — streaming it live.

4

Ship

You get a tested, documented, deployable project with a side-by-side diff explaining every decision.

Migration paths

Modern stacks, on rails

Battle-tested routes today — more added continuously.

Everything in the box

A full modernization team, automated

The work of an agency engagement — analysis, rewrite, tests, docs, deploy — in one engine.

Smart Codebase Analysis

Maps dependencies, detects the framework, and flags risks before any code is touched.

Intelligent Rewriting

Restructures following clean architecture and current conventions — not just syntax translation.

Frontend Redesign on Demand

Rebuild the UI while migrating — modern, responsive, accessible, in the style you pick.

Auto-Generated Tests

Every migration ships with a test suite, so you know the new code behaves like the old.

Side-by-Side Diff Viewer

Old vs. new, line by line, with an explanation for every decision the engine made.

Dependency Modernization

Swaps outdated, vulnerable libraries for secure, maintained alternatives.

Documentation Generator

Full docs for the migrated codebase — README, API docs, inline comments.

One-Click Deploy

Push the modernized app straight to Vercel, Netlify, or your own server.

Pricing

Pay per migration. No subscriptions.

Priced on codebase size and complexity. Your first migration is free.

Starter

Free

Your first migration, on us.

  • Full codebase analysis
  • One complete migration
  • Auto-generated tests
  • Diff viewer & docs
Start free
Per project

$500–$2,000

Based on size & complexity.

  • Everything in Starter
  • Unlimited file count
  • Frontend redesign on demand
  • Dependency modernization
  • One-click deploy
  • Priority engine throughput
Modernize a project

FAQ

Frequently asked questions

Everything about AI-powered legacy code migration, answered.

What is CodeShift?+

CodeShift is an AI code modernization engine. You upload a legacy codebase (or import a GitHub repo); it analyzes the whole project, plans the migration, rewrites it into a modern stack in dependency order, verifies every file for behavior parity, and hands back a tested, documented application with a side-by-side diff.

Which legacy code migrations does CodeShift support?+

PHP to Laravel 11, jQuery to React 18, WordPress to Next.js 14, Python 2 to Python 3.12, AngularJS to React, and vanilla JavaScript to Vue 3 — with more migration paths added continuously.

How is this different from asking ChatGPT to rewrite my code?+

A chat model rewrites one snippet at a time with no view of the whole system. CodeShift builds a dependency graph of your entire codebase, migrates files in the right order so imports stay consistent, injects already-migrated symbols into each rewrite, and runs a closed-loop verifier that checks behavior parity per file and auto-repairs failures.

Is the migrated code actually tested?+

Yes. Every file passes structural checks and an adversarial AI behavior-parity review, failures are repaired automatically, and the finished migration ships with an auto-generated test suite plus per-file confidence scores.

How much does an AI code migration cost?+

Your first migration is free — no credit card required. After that, pricing is per project based on codebase size and complexity, typically $500–$2,000, with no subscription.

Is my source code private and secure?+

Your code is processed solely to produce your migration, is never used to train models, and GitHub imports request read-only access via OAuth that you can revoke at any time.

How long does a migration take?+

Hours, not months. Analysis takes minutes; the rewrite streams live so you watch files being modernized in real time, and a typical small-to-medium codebase completes the same day.

The code you're scared to touch,
turned into something you're proud to ship.

Built for freelancers, agencies, and teams sitting on aging code. Stop dreading the rewrite.

Start your free migration