Joseph Tso is Co-Founder at Haladir, an AI-powered mainframe modernization suite that helps enterprises transform legacy COBOL systems into modern languages. Haladir is part of Y Combinator's Winter 2026 batch and has raised pre-seed funding from investors including Susa Ventures.

Joseph studied Computer Science at Princeton University with research interests in operations research and machine learning. He brings technical expertise in AI and formal verification to solve complex enterprise infrastructure challenges.

Joseph co-founded Haladir in 2025 alongside Jibran Hutchins, Quan Huynh, and Preston Schmittou to address the critical need for mainframe modernization. The company's technology uses property-based testing and custom models to preserve business logic during code translation.

Haladir's documentation product generates comprehensive analysis from millions of lines of COBOL code, while its translation tool migrates legacy languages to Java and C# .NET. The company is based in San Francisco with a team of 4 employees.

Haladir tackles a massive enterprise problem, as many Fortune 500 companies still rely on mainframe systems running COBOL code written decades ago. The company's AI-powered approach enables organizations to modernize without months of manual analysis and rewriting.