Rewrite your legacy codebase in weeks. Multiple modern stacks. Tests included.

Leap Agentic rewrites legacy codebases (PHP, Ruby on Rails, Java/Spring, .NET Framework) into one or more modern stacks (TypeScript, Python, Rust, Go) in 4–12 weeks. We deliver behavior-parity tests that prove the new code matches the old, plus agent-readable specifications that document the system. You pick the stack that wins.

How it works

1. We extract specs from your existing codebase. Automated analysis plus 2–3 working interviews with your engineers. Output: a structured specification of every behavior in the system.
2. We generate N implementations in parallel. One spec, multiple target stacks. Engineers write the contract; AI agents under the LEAP Protocol generate the code; senior reviewers gate every PR.
3. We deliver tests that prove behavior parity. Every spec entry produces a test. Tests run against both the old and the new code and must pass on both. You see green before anything ships.

Why multiple stacks at once

Most modernization shops pick one target stack and lock you in. Parallel multi-stack delivery solves real business problems:

• Hedge language risk. Don’t bet the company on a single ecosystem.
• A/B test stacks. Ship two implementations of the same service; measure latency, hiring pipeline, ops cost.
• M&A flexibility. Acquirer wants Java? Buyer wants Rust? You have both.
• Bench arbitrage. Hire from whatever talent pool is hot. The spec is the contract.

This is only possible because the LEAP Protocol treats specs as source of truth and code as commodity. Public proof: sqlite-leap — five SQLite engines (C, Rust, Zig, Go, Python) from one neutral spec.

Proof artifacts

• sqlite-leap — multi-language rewrite of SQLite generated from one specification.
• semver-leap — full rewrite of npm’s node-semver. 5,632 tests passing against the upstream test suite.
• LEAP Protocol — the open-source methodology itself.

Who this is for

• CTOs with a legacy codebase that’s been “in the rewrite queue” for over a year.
• M&A targets with messy tech debt blocking a deal close.
• Heads of Platform hedging language-vendor / cloud-vendor risk.
• Founders post-acquisition rationalizing a portfolio’s stacks.

How long it takes

• Scoping call: 30 minutes. Free.
• Fixed-price proposal: within 5 business days of the call.
• Delivery: 4–12 weeks depending on codebase size and number of target stacks. Multi-stack runs add days, not months.

Pricing

Fixed-price per engagement. Typical range: $40,000–$120,000. The proposal locks the scope, the timeline, and the deliverable. No T&M creep.

Engage

• Email: sales@leapagentic.io
• Direct: Book the 30-minute scoping call

Leap Agentic is an AI-native software delivery firm founded in 2026 by David Pierini and Stanislav Synko, headquartered in Sheridan, Wyoming. We are not affiliated with Legacyleap.ai or Impetus Leap AI.

Leap Agentic is distinct from Legacyleap.ai and Impetus Leap AI.