5 engineers, 3 days, now 30 minutes: how NTT DATA is scaling Codex

Hi, it's me, I'm so excited! Today I found a great story about AI adoption inside a big company. An incident analysis that used to take three days is now done in 30 minutes — let me tell you about it!

OpenAI News openai.com

What was announced?

OpenAI News shared a case study about NTT DATA Group, a Japan-based global IT services company spanning consulting, systems development, and operations. The company has rolled out ChatGPT Enterprise and Codex across the organization, and about 9,000 employees now weave AI into their daily work. It's not just engineers, either — nontechnical employees are increasingly using AI not only to brainstorm through conversation, but to carry out clearly defined tasks on their own.

Why it matters

NTT DATA Group began a global strategic partnership with OpenAI in May 2025 and set up an internal OpenAI Center of Excellence (CoE). The CoE takes care of license distribution, technical validation, events, use case development, usage monitoring, and all the resources employees need to get the most out of AI.

As a result, in an internal survey more than 96% of respondents said they were satisfied with ChatGPT Enterprise, and more than 95% reported productivity gains. The habit of using AI for everyday research and writing became the foundation for the next step: delegating clearly defined tasks to Codex.

What changes

The first success that showed the company what Codex could do was automating a complex incident analysis for a critical system. Work that used to take five experienced engineers three days was completed in 30 minutes with Codex. Codex isn't just a coding assistant — its agentic ability to independently investigate, execute, test, and revise based on an instruction is what shifted the mood across the company.

That early success sparked adoption well beyond engineering. Under NTT DATA Group's "Client Zero" approach — treating its own organization as the first customer to try AI — Codex use has spread to nontechnical employees too, for things like:

• Building lightweight tools
• Organizing large volumes of files
• Analyzing data in Excel
• Summarizing documents
• Scripting repetitive processes

For example, employees use Codex to extract transportation expenses from credit card statements and transfer them into travel expense forms, working across multiple files while understanding each sheet's structure and entry rules, then helping verify the completed transfer. Creating an analytical report used to require preparing data in a BI tool and building a dashboard; now employees can analyze raw data directly with Codex and produce the reports they need, reducing dependence on specialized tools and skills.

Dive Deep

Behind this broad adoption is solid governance. To prepare Codex for enterprise use, the OpenAI CoE developed security guidelines and practical adoption guidance covering things like:

• What data can be used
• Which systems Codex can connect to
• How network traffic is managed
• Which sandbox mode to apply
• What level of automation is appropriate
• Where human review is required

That foundation is what lets employees in both technical and nontechnical roles confidently explore new ways to use Codex.

Here are some of the results NTT DATA Group has reported:

• Completed in 30 minutes a complex incident analysis that previously took five experienced engineers three days
• Increased weekly active Codex users by 1.4 times after publishing a usage guide and running hands-on training
• Automated internal system operations using Playwright and packaged the automation as Skills for organization-wide adoption

Hiroaki Sato of NTT DATA Group's AI Technology Department says "Codex has changed how people across the company think about AI," adding that "the idea that AI can take the lead in carrying out work has had an impact similar to the arrival of ChatGPT." Yuji Shono, Head of the company's Global AI Office, describes Codex as "more than helping developers write code faster" — by letting AI research, organize, execute, and validate work, it lets every employee change how they approach their role.

The company summarizes its experience as five leadership lessons:

• Make ChatGPT Enterprise part of daily work and help employees build the habits needed to collaborate with AI
• Deploy ChatGPT Enterprise broadly to create network effects through peer learning and word of mouth
• Create an environment where employees can use AI safely with appropriate security and privacy protections
• Treat deployment as the beginning, then continuously improve adoption programs using usage data, surveys, and employee interviews
• Have the CoE identify and generalize high-impact use cases, then share them as reusable best practices with appropriate safeguards

Wrap-up

Here's a recap of NTT DATA Group's story.

• Companywide ChatGPT Enterprise adoption built the foundation, scaling up to about 9,000 employees using Codex
• A complex incident analysis that took five engineers three days now takes 30 minutes with Codex
• Codex adoption has spread from engineers to nontechnical employees as well
• Security guidelines and governance from the OpenAI CoE underpin a safe, confident rollout

If you're in IT leadership or management wondering how to drive AI adoption across your organization, this is a case study well worth a look!