Simplex rethinks software development with Codex

Simplex is a technology partner that works across consulting, systems development, and operations. To improve productivity in systems development, the company has quantitatively measured the impact of generative AI and applied those learnings across multiple projects. Building on that experience, Simplex is now evaluating generative AI use across all projects and advancing AI-native delivery in applicable projects, with the goal of improving productivity across the organization.

After ChatGPT launched in 2022, Simplex established a center of excellence in 2023 to create the foundations for employees to use AI and to validate AI-native development processes. Building on that work, the company adopted ChatGPT Enterprise across the organization and selected Codex as its primary coding agent, accelerating an effort to rethink how software development gets done.

Inside the rollout

In traditional software development, people typically divide work across requirements definition, design, implementation, testing, and operations. Tasks such as interpreting design documents, deciding how to implement a feature, defining review criteria, and isolating or fixing defects often depend on the experience of individual contributors. As a result, quality and development speed can be shaped by individual skill and by how knowledge is shared across the team.

As generative AI started to spread through software development, it was often used as an assistive tool for human developers. More recently, agentic systems have made it possible to delegate multi-step tasks to AI. In development environments, AI is starting to move beyond support and take on work that advances projects directly.

To scale that shift, Simplex adopted ChatGPT Enterprise as the foundation for company-wide deployment and uses Codex as its main coding agent.

—Kazuya Ujihiro, Executive Principal, Simplex

Results at a glance

Through that work, the company has measured meaningful time savings across multiple stages of development: