Per Diem Travel Claim Builder: Consistent, Receipt-Light Reimbursement

The problem this kills

Per-diem reimbursement is supposed to be the easy kind — no shoebox of receipts, just a rate per day. In practice it's a quiet mess. The rate depends on which city the traveler was in and which date it was. The first and last travel days are usually paid at a partial rate. Every meal that was already provided — a conference lunch, a hotel breakfast, a hosted dinner — has to be subtracted at the right amount. Multi-city trips mean different rates on different days of the same trip. And the person doing the math is usually copying numbers out of a rate table into a spreadsheet by hand, late, under deadline.

So you get inconsistency (two travelers on the same trip claim different amounts), errors (the partial-day rule applied to the wrong days, or a provided meal nobody deducted), and slow approvals (the approver can't tell whether the number is right without redoing the whole calculation). For government contractors, nonprofits, and consultancies that reimburse on a per-diem basis, this is both an audit risk and a constant low-grade time sink. The fix isn't more discipline — it's a tool that knows your rate table and your rules and does the arithmetic the same way every time.

What you'll build

A simple internal web tool for your finance team and travelers. You load your per-diem rate table — the daily allowance (and meal breakdown) by city and effective date, GSA/CONUS-style. A traveler enters their itinerary: the dates, the city for each leg of the trip, and which meals were already provided each day. The tool computes the full allowance: it picks the right rate for each day and city, applies your first/last-day partial rate (often 75%), and subtracts the right amount for every provided meal — then shows the day-by-day math so nothing is a black box. The approver reviews the computed claim, sees exactly where each deduction came from, and clicks Approve or Send back. Only after approval does the tool export a reimbursement CSV in your payroll/AP columns plus a clean per-traveler claim summary.

What's inside the Implementation Plan

The downloadable plan is a step-by-step file you paste into an AI coding agent. It opens by interviewing you about your business — your travel-reimbursement process and who runs it, the systems and spreadsheets involved, the exact shape of your rate table and its meal breakdown, your real first/last-day rule, how you handle multi-city trips, and your messy edge cases (partial-day meals, international/non-table cities, mid-trip rate changes). It reads a short spec back to you for a thumbs-up, then builds the tool around your rules instead of a generic GSA template. From there it walks the agent through the data model, the rate-table import, the itinerary entry screen, the per-diem computation engine (partial days plus meal offsets), the approver review-and-sign-off gate, and the reimbursement CSV and claim-summary exports. Every step ends with a ready-to-copy prompt.

The governance it includes (this is the point)

This isn't a toy calculator. The plan builds in the controls a real finance function needs: login so only your team can use it, row-level security so people only see their own organization's claims, a complete audit trail of every computation, edit, and approval (who, what, when, and why), a hard human-approval gate so nothing is reimbursed until a person reviews the math and signs off, and duplicate guards so the same traveler-and-trip can't be claimed twice. The AI does the consistent arithmetic; a person owns the decision to pay.

Who it's for

Finance and payroll teams — and the travelers who file claims — at organizations that reimburse on a per-diem basis: government contractors, grant-funded nonprofits, and consultancies. If you can describe your rate table and your partial-day and provided-meal rules, you can build this.

You've got this — open the plan, paste the first prompt, and you'll be computing your first real per-diem claim this weekend.