21 Jul Workday and AI: What Per-Call Agent Billing Means for HR Departments
Key Takeaways
- Workday acquired several AI companies (Sana, Paradox, HiredScore, Evisort) over roughly 18 months, building one unified AI stack for HR and finance.
- According to industry analysis, Workday AI billing now runs on Flex Credits, a cost unit charged per agent action, ranging from 1 to 750 credits depending on task complexity.
- The per-call model means costs rise with AI usage, unlike the flat per-seat pricing HR teams are used to.
- Open source HCM platforms like MintHCM let organizations connect any AI model (Claude, GPT, Gemini) through built-in MCP, without an extra fee for each call.
Introduction
Workday AI billing is changing the economics of AI-driven HR automation. One of the largest HCM vendors spent close to $3 billion in under two years acquiring AI companies, while at the same time rewriting how it charges for agent activity. Instead of paying for a seat in the system, customers may now start paying for every AI call. This article explains what that means in practice, and how the open source alternative looks by comparison.
What’s behind Workday’s AI acquisitions?
Over the past several quarters, Workday acquired a series of AI-focused companies: Sana (valued at roughly $1.1 billion), Paradox, HiredScore, and Evisort. The goal was to build one unified AI stack spanning recruiting, learning, and document processing, rather than integrating third-party tools.
According to the industry analysis Workday’s $3B Bet: A New Operating System for AI Agents, Workday is simultaneously introducing a new billing model built on so-called Flex Credits, a cost unit charged per agent action, ranging from 1 to 750 credits depending on task complexity. This is the only source detailing these specifics in this form, so the figures should be treated as an analyst estimate rather than Workday’s official pricing.
How does Workday AI billing affect HR budgets?
The classic per-seat model, paying based on the number of users, is predictable: cost scales linearly with headcount. The per-call model works differently: cost scales with the number of actions an AI agent performs. The more questions a team asks the system, the more automation an HR department runs, the higher the bill at the end of the month.
There’s a second layer to this: Workday launched the Agent System of Record, a central point through which all AI agents touching HR and finance data are meant to pass, whether built by Workday or by third parties. This means that even an external agent, if it needs to reach Workday data, goes through the same vendor-controlled access point.
You’re not paying for access to AI, you’re paying for using it, and the better your HR automation works, the higher the bill.
What does AI billing look like in open source HCM?
MintHCM, as an open source HCM, takes the opposite approach to AI integration: the system has a built-in MCP server that lets any AI model, Claude, GPT, Gemini, or another, read data, create records, and perform actions directly inside the system. The choice of model belongs to the organization, not the HCM vendor, and the cost of using AI depends on the agreement with the chosen model provider, not on an extra fee charged by the HR system per call.
The table below compares both approaches across four areas that matter most when choosing a system.
| Area | Workday (closed AI stack) | Open source HCM (MintHCM) |
|---|---|---|
| AI cost control | Per-call billing (Flex Credits), cost rises with usage | AI cost depends on the agreement with the chosen model provider, not the HCM |
| AI model choice | Models built into Workday’s stack | Any model: Claude, GPT, Gemini, self-hosted model |
| Agent access point | Centralized gateway controlled by the vendor | Open MCP protocol, no vendor-controlled central point |
| Auditability | Depends on vendor policy | Full access to the system’s source code |
Frequently Asked Questions
How much has Workday spent on AI acquisitions?
According to industry reports, Workday spent close to $3 billion over roughly 18 months acquiring Sana, Paradox, HiredScore, and Evisort.
What are Flex Credits in Workday AI billing?
According to industry analysis, they’re a billing unit charged per AI agent action, ranging from 1 to 750 credits depending on task complexity.
What’s the difference between per-call and per-seat billing?
Per-seat means a flat cost based on the number of users. Per-call means cost that grows with the number of AI agent actions, in other words, with how intensively automation is used.
Can a Workday customer use a different AI model than the one built into the system?
The Agent System of Record also governs third-party agents that reach into Workday data, meaning even external models pass through the same vendor-controlled access point.
How does open source HCM like MintHCM approach AI costs?
MintHCM has a built-in MCP server and lets organizations connect any AI model without an extra per-call fee from the HR system itself, cost depends solely on the agreement with the chosen model provider.
Sources
- Workday’s $3B Bet: A New Operating System for AI Agents. THE DAILY BRIEF, 2026.
- Workday to Acquire Sana for $1.1 Billion. PRNewswire, 2025.
- Workday Completes Acquisition of Paradox. Workday Newsroom, 2025.