Architecting Financial Logic for the Web: Building an IOLTA 3-Way Reconciliation Tool

Description and use

A web-based IOLTA reconciliation tool uses integer arithmetic to guarantee exact three‑way balance matching and automates compliance notifications.

Problem

Web applications often rely on floating‑point math, which is unsuitable for legal trust accounting where every cent matters.

Outcome

The tool guarantees zero‑tolerance variance, automates compliance notifications, and integrates seamlessly with the company’s B2B SaaS.

Workflow

• Sanitize user input (strip symbols, commas, spaces)
• Convert sanitized string to float, multiply by 100, round to integer
• Compute adjusted bank balance, book balance, and client ledger sum using integers
• Compare the three values for exact match
• If mismatch, calculate variance and identify failing pillar
• Display compliant or error state to user
• Capture intent and trigger backend webhook via Make.com
• Use Resend to send transactional email with dynamic tags
• Route secure email to client list via Firebase

Evidence

If Adjusted Bank Balance != Book Balance or Book Balance != Sum of Client Ledgers, the firm is out of compliance and faces immediate audit risk.

Source

To ensure strict compliance in the calculator, all user inputs must be intercepted, sanitized, and converted into integers before any mathematical operations occur.

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By utilizing Make.com to handle our backend webhooks and Resend for transactional email delivery, we can automate the exact pain points the calculator brings to light.

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