# William Reviews
**Vendor:** Certifi  
**Category:** [Insurance Billing Software](https://www.g2.com/categories/insurance-billing)
## About William
William™ by Certifi is purpose-built premium billing and payment software for health plans and health insurers. Unlike billing modules bundled into core admin platforms, William™ is designed from the ground up to handle the complexity of health plan billing — including ACA marketplace, Medicare Advantage, Medicaid, and commercial lines of business. Built on the Perfect Balance™ accounting architecture, William™ enforces balanced debits and credits at every transaction, virtually eliminating the manual reconciliation work that plagues teams using legacy or core admin billing systems. Key capabilities include: Automated invoice generation, retroactive adjustments, and payment matching Integrated member payment portal (ACH, credit/debit card, retail cash) Configurable delinquency management with automated letter generation Real-time billing data via API for member portals and service teams No-code billing rule configuration — no developer required Integration with upstream enrollment platforms and downstream GL systems via API, flat file, or SSO William™ is PCI, NACHA, SOC2, and HIPAA compliant and is designed to scale to millions of transactions per month.






- [View William pricing details and edition comparison](https://www.g2.com/products/william/reviews?section=pricing&secure%5Bexpires_at%5D=2026-05-14+20%3A21%3A51+-0500&secure%5Bsession_id%5D=2625b5f1-05f9-42eb-8c99-932fc08e77c6&secure%5Btoken%5D=f5c02a5bf189b56e809ad54bb94001eb70a8b639207694d17c4f860a6a37e6ec&format=llm_user)


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