Internal GenAI Team: Python, FastAPI, LangChain

The Big Four professional services firm is one of the world's largest professional-services firms: hundreds of thousands of professionals across hundreds of cities and over a hundred countries, with tens of billions in annual revenue and multi-billion-dollar technology and AI investment. The firm operates as a transformation orchestrator combining alliance technologies (the global technology company, Google Cloud, Salesforce, SAP, Adobe, Zuora, AWS, OpenAI, Harvey) with proprietary accelerators (their transformation methodology, their business transformation framework, their finance accelerator, their governance platform, their agentic operating system, the firm's internal platform, their proprietary AI accelerator). Taller's engagement at this firm spans the co-developed their cloud governance platform plus a sustained multi-pod practice across cloud DevOps, SRE, microservices and API engineering, Adobe Experience Manager, the firm's internal GenAI team, Cloud Security, DevSecOps, IAM, and a Data and System Architect track active in 2026. Four cases below: the cloud governance platform, plus three engagements that the report did not propose but are central to Taller's the Big Four professional services firm story.

The Big Four professional services firm's internal AI investment under their agentic operating system and the firm's internal platform umbrella requires Python, FastAPI, and Langchain engineering capacity that can integrate with the firm's existing API management, Kubernetes, and Istio infrastructure. The firm's own AI tooling cannot rely entirely on alliance products; the work that sits closest to the Big Four professional services firm's intellectual property has to be built inside the firm.

Taller engineers contribute capacity to the Big Four professional services firm's internal GenAI team as Backend Developers, designing, developing, and maintaining the Big Four professional services firm's Generative AI tools using Python, FastAPI, and Langchain, publishing APIs and microservices through the Big Four professional services firm's API management, deploying onto Kubernetes with Istio service-mesh policies, and developing SDKs against the Big Four professional services firm's APIs. Taller's production agentic AI experience is anchored in the major US airline portfolio, which covers LangChain, LangGraph, AWS Bedrock, knowledge graphs, RAGAS evaluation, and multi-agent workflows.

Sustained individual contributor capacity into the Big Four professional services firm's GenAI program from 2024 forward, position-level presence inside the Big Four professional services firm-managed function.

The Big Four professional services firm's AI rollout outcomes are significant: hundreds of thousands of M365 Copilot users across the firm, millions of Copilot actions per month, hundreds of thousands of hours of capacity created per month, hundreds of millions of dollars saved from Copilot use, and fifty-four percent of the workforce using AI weekly. These outcomes belong to the Big Four professional services firm and reflect the firm's full AI investment program. Taller's GenAI engineers contribute capacity to the internal tooling underneath the broader program; the strategy and the headline outcomes are the Big Four professional services firm's.