Should you build or buy Enterprise AI Assistant Platform?
Enterprise AI assistant platforms give employees a company-wide chat interface to large language models, wired into single sign-on, document and email connectors, and admin controls for retention and audit. Buyers are IT and security teams standardizing how the whole workforce reaches AI rather than leaving it to individual browser extensions.
Copy reviewed 2026-09-27 · Research revision 2026-09-22
Sources: microsoft.com; docs.openwebui.com
Treat the seat as a convenience purchase, not a platform commitment. Buy seats where employees live in Microsoft or Google apps, keep contracts short, and expect a self-hosted assistant over your own data to be a realistic option; several large enterprises already run both side by side.
Build it, buy it, or bridge?
When building makes sense
Building an enterprise AI assistant is a live option, not a fringe one. Aon's AonGPT runs on Azure for more than 62,000 colleagues with over 6.4 million messages exchanged, and Mott MacDonald's EMMA reached 20,000 employees and handled 220,000 queries within nine months, both assembled from cloud AI services rather than bought as a finished seat. Samsung Semiconductor deployed Open WebUI on its own Kubernetes cluster in a 30-day rollout, keeping data on-prem while reaching 40% adoption in the first week. What gets built is the chat interface, connectors, and access control; the underlying model intelligence is rented either way, from a frontier lab or an open-weight source. Build when you have platform engineers to own SSO, logging, and connector maintenance long term, and when keeping data off a vendor's servers outweighs turnkey support. The work itself is generic, so the payoff is cost control rather than an edge.
When buying makes sense
Buying a seat is the convenience purchase for most employees, and it should be treated that way rather than as a platform commitment. Claude for Work and Microsoft 365 Copilot list at $20-$30 per user per month, with Google Workspace bundles at $27-$35, and each arrives with SSO, admin controls, audit logs, and in-app connectors already built. That buys speed: no engineering team, no Kubernetes cluster, no red-teaming pipeline to stand up. But per-user inference on a self-hosted model can run $0.45-$4 a month, far below a seat price, and enterprises including Astellas, Public Storage, and PayU already run self-hosted assistants in production, which means the vendor's pricing power here is thinner than the sticker suggests. Keep contracts short, buy seats where employees live inside Microsoft or Google apps, and revisit the build option before any multi-year renewal, because the underlying inference is commodity.
The desk read
Build-versus-buy analysis for Enterprise AI Assistant Platform is being written. In the meantime, the framework that drives every B4 call is on the B4 Index page.
Frequently asked
What is an enterprise AI assistant platform?
An enterprise assistant standardizes how staff reach AI models through one governed chat interface instead of individual browser extensions. Vendor seats list at $20 to $35 per user monthly, but large enterprises including Aon and Samsung Semiconductor already run comparable assistants on cloud AI services they built themselves.
Can a company realistically build its own AI assistant?
Yes, and several already have. Aon's AonGPT serves more than 62,000 colleagues on Azure, Mott MacDonald's EMMA reached 20,000 employees in nine months, and Samsung Semiconductor runs Open WebUI on its own Kubernetes cluster. The work is buildable; it just carries little competitive edge once built.
Why should we be cautious about locking into a long-term seat contract?
Because the vendor's position is weaker than the seat price implies. Per-user inference on a self-hosted model can cost a few dollars a month against a $20-$30 seat, and multiple large enterprises already run both a vendor seat and a self-built assistant side by side, so a long contract locks in a price the underlying economics don't support.
Should we still buy seats at all?
For most employees, yes, as a short-term convenience purchase. Vendor seats bundle connectors, SSO, and admin tooling that would take months to replicate. Keep contracts short and revisit before any multi-year renewal rather than treating the seat as a permanent platform decision.
What are the main enterprise AI assistant vendors?
Representative vendors include ChatGPT Enterprise, ChatGPT Team, Claude for Work, Gemini for Google Workspace, Microsoft 365 Copilot. B4 Pro includes the category score and the full vendor list.