# Excel to Custom Web App Migration in 10 Days > Turn complex Excel spreadsheets into a secure, multi-user custom web app with role permissions and live dashboards in 10 to 14 days. Source: [https://aergent.nl/en/excel-to-webapp](https://aergent.nl/en/excel-to-webapp) Language: English Excel & Spreadsheet Modernization • Live in 10 to 14 Days # Transform Fragile Excel Spreadsheets. Into a Secure, Multi-User Web App in 10 Days. Is your company running on a complex, 20-tab Excel file with broken formulas and version conflicts? We engineer your spreadsheet logic into a secure, customized web application with user logins, role permissions, automated backups, and live dashboards. View Packages & Architecture - Live Within 10 to 14 Business Days - 100% Formula & Calculation Accuracy - Multi-User Role Permissions & Audit Log - 100% Full Code & Database Ownership 10–14 Days Turnkey Delivery 0 Errors Formula Integrity 100% Your Code & DB 0 Rent Zero Per-User SaaS Fees 01 / Operational Risk Fragile spreadsheets limit operational throughput. Bottlenecks ## The Hidden Risks of Running Your Business on Excel Spreadsheets are great for scratchpads, but dangerous for core company operations. 01 / RISK ### Version Conflicts & Overwrites Team members editing different files leading to lost customer data and sync conflicts. 02 / RISK ### Broken Formulas & Silent Errors One accidental formula overwrite can silently distort financial quotes and pricing calculations. 03 / RISK ### Zero User Access Control Anyone with file access can view sensitive margins, salaries, customer lists, and financial records. 04 / RISK ### Terrible Mobile Experience Spreadsheets are nearly impossible to navigate and update cleanly on iPhones and tablets. 05 / RISK ### No Automated Backups or Audits No way to trace who changed what cell, when, or why if a calculation breaks. 06 / RISK ### No External API Integrations Cannot automatically push orders to Exact Online, send WhatsApp updates, or trigger emails. 02 / Transformation From fragile files to hardened multi-user software. Comparison ## Excel Spreadsheets vs. Custom Aergent Web Application Upgrade from fragile grid cells to an enterprise-grade internal operations tool. Capability Old Excel / Google Sheets Custom Aergent Web App Multi-User Concurrency File lock conflicts & sync crashes Real-Time Multi-User Database Role-Based Access Everyone sees all columns & tabs Custom Admin / Staff / Client Roles Formula Protection Accidental cell deletes & typos Hardened Backend Calculation Engine Mobile & Tablet UX Pinch-to-zoom nightmare Flawless Responsive Web Interface Audit Trail & Backups Manual "Save As_v2_final.xlsx" Automated Daily Backups & History Log Third-Party Connections Manual copy-pasting into tools Direct API Sync with CRM & Accounting 03 / Fixed Pricing Turnkey sprints with zero recurring per-user rent. Packages ## Transparent Migration Packages Select the scale of your spreadsheet migration. Fixed price quotes before kickoff. 1 to 3 Sheet Workflows / Calculators 10 Days Delivery ### Single-Workflow App Ideal for custom pricing calculators, project quotation tools, or inventory tracking spreadsheets. €1,750 one-time fixed (ex. btw) Full Migration of Complex Formulas & Logic Role-Based Login (Admin & Staff Users) Automated Database with Daily Backups 1-Click Export to Excel & PDF Reports Mobile & Tablet Responsive Interface 1-on-1 Video Training Handover 30 Days Dedicated Post-Launch Support ★ MOST POPULAR Complex Multi-Tab Enterprise Sheets 14 Days Delivery ### Full Operations Hub Comprehensive web app replacing mission-critical operations spreadsheets across your entire company. €2,850 one-time fixed (ex. btw) Full Multi-Department Workflow Migration Advanced Granular Permissions & Team Roles Live Analytical Dashboards & Visual Charts Direct API Sync (Exact Online / Moneybird / AFAS) Automated Email & WhatsApp Notifications Customer Portal View Option (Restricted Login) 60 Days Dedicated Support & Nazorg 04 / Protocol Two-week structured sprint from audit to live ownership. Roadmap ## Our 14-Day Migration Roadmap A structured, precision sprint ensuring 100% calculation accuracy and zero disruption. 01 Day 1–3 #### Data Model & Formula Extraction We dissect your Excel formulas, sanitize historical data, and design the relational PostgreSQL database schema. 02 Day 4–9 #### Custom Web Application Build Our Amsterdam engineers build the modern UI, code the calculation engine, and implement secure role permissions. 03 Day 10–12 #### Data Migration & Verification Audit We import your historical spreadsheet data and run 100+ mathematical test cases to guarantee zero calculation discrepancies. 04 Day 14 #### Team Handover & Go-Live Your new web app goes live with recorded video walkthroughs and full source code / database ownership transferred to you. 05 / Standards Engineered for security, speed, and outright ownership. Architecture ## Why Our Web Apps Accelerate Your Business Engineered for speed, data security, and long-term business scalability. ### Rock-Solid PostgreSQL DB Your data is stored in an ACID-compliant relational database with automatic daily snapshots. ### Granular Role Permissions Ensure staff only see the data they need to perform their work, keeping margins and finances private. ### Work From Any Device Review numbers, create quotes, and update project statuses on the road via mobile or tablet. ### Audit Trail & Activity Log Know exactly who modified a record, created a customer, or approved a quote with full timestamps. ### 1-Click PDF & Excel Exports Generate beautifully branded customer proposals or export raw tables to CSV in 1 second. ### 100% Code Ownership You own the complete codebase and database. No monthly subscription rent per employee. FAQ ## Frequently Asked Questions 14-Day Delivery Guarantee ## Ready to upgrade your Excel sheets to a modern web app? Eliminate formula errors and version chaos in 14 days. Claim your migration blueprint now.