NS File → Tax Invoice Auto-Linking – Lendly
Automatically connecting daily NS files to the correct invoices and keeping totals accurate at all times.
Problem Statement
The Solution
Automation Overview
We built a dedicated Airtable automation layer that automatically connects every NS file to the correct Tax Invoice based on date logic. The moment an NS file is added or updated, the system identifies which invoice period it belongs to, links it instantly, and lets Airtable handle the total calculation using rollups. The result is a completely dynamic, always-accurate invoicing system.
Automatic Invoice Period Detection
Each Tax Invoice record contains: Start Date, End Date. When an NS file is created or updated, the automation compares the NS file’s date against all invoice ranges and identifies the exact invoice it belongs to. No searching. No guesswork.
Instant NS File → Invoice Linking
Once the correct invoice is identified: The NS file is automatically linked to that Tax Invoice. No drag-and-drop. No manual selection. No risk of linking to the wrong month. Everything stays perfectly organized.
Rollup-Based Gross Calculation
Each Tax Invoice uses Airtable rollups to: Sum Gross values from all linked NS files, Update totals instantly whenever data changes. If: A Gross value is corrected, A date is adjusted, A file is re-linked. The invoice total updates automatically.
Fully Dynamic & Self-Correcting System
If an NS file’s: Date changes, Gross value changes, Placeholder becomes a real value. The automation re-evaluates the invoice mapping and ensures the NS file is always linked to the correct invoice. No stale data. No mismatches.
Zero Manual Reconciliation
Because everything is automated: No manual checks, No recalculations, No end-of-month panic. Invoices are always ready.
Integrations & Connected Systems
Airtable – NS Files table, Tax Invoices table, linked records, rollups; n8n / Airtable automation logic – Date comparison and record linking; Date-range matching system – Ensures accurate invoice assignment. All logic runs silently in the background.
Smart Logic & Reliability
- Prevents incorrect invoice linking
- Handles late or updated NS files gracefully
- Supports placeholder records
- Auto-relinks when dates change
- Guarantees invoice totals are always correct
- Eliminates human error entirely
- The system behaves like a purpose-built internal finance tool
Before
Teams manually searched invoice periods, linked files by hand, and rechecked totals repeatedly.
After
Every NS file automatically finds its place, invoices update themselves, and totals are always correct.
Tools Used
Our Process
Discover
Identified friction in manual invoice reconciliation.
Design
Created a date-driven linking logic tied to invoice periods.
Build
Implemented automated matching and rollup-based totals.
Integrate
Connected NS Files and Tax Invoices seamlessly.
Deploy
Tested edge cases like date changes and placeholders.
Business Impact
Zero manual invoice linking
Always-accurate invoice totals
No reconciliation errors
Faster month-end closing
Fully dynamic and self-updating invoices
Clean, audit-friendly financial records
A scalable finance system that grows with data volume
"This automation completed Lendly’s financial workflow by turning invoicing into a fully automated, self-maintaining system. NS files now connect themselves to the correct invoices, totals update instantly, and finance teams never need to intervene — even as data changes."
Want a system like this for your business?
Let’s build it.