Custom CRM/ERP Web Application Development

Custom CRM/ERP Web App for Sales, Contracts, Installations & Automation Job Description We are looking for an experienced Full-Stack Developer to build a custom web-based CRM/ERP system for our company, Aquantia, a Spanish company selling and installing water purification systems. We do NOT want Odoo or another existing ERP implementation. We want a clean, simple and scalable custom web application built around our actual business workflow. This is Phase 1, but if the project is successful, we intend to continue working with the developer long-term and add more functionality as the company grows. COMPLETE WORKFLOW Meta Lead Ads → CRM → Automatic WhatsApp → Call/Follow-up → Sale → Contract → Electronic Signature → Financing → Installation → Delivery/Installation Document → Invoice → Commission → Warranty/Maintenance 1. META LEAD ADS INTEGRATION * Leads from Meta Lead Ads must automatically enter the CRM. * Store lead name, phone, email and form information. * Store lead creation date and time. * Store Meta source information whenever available: campaign, ad set, ad/form/source. * Avoid duplicate leads where possible. 2. AUTOMATIC WHATSAPP When a new Meta lead enters the CRM: * Automatically send an initial WhatsApp message. * Use the official WhatsApp Business Platform/API or an appropriate compliant provider. * Store the WhatsApp action/status in the customer’s activity history. * Explain clearly any external WhatsApp/API costs before development. We do NOT simply want a button that opens WhatsApp. The initial message must be sent automatically. 3. CRM & SALES PIPELINE We need a visual sales pipeline with customizable stages such as: New Lead → Contacted → No Answer → Interested → Follow-up → Sale → Financing → Installation → Completed / Lost Each lead/customer should have a complete profile containing: * Contact details * Lead source * Salesperson * Notes * Tasks/follow-ups * Documents * Sale information * Financing information * Installation information * Invoice * Warranty/maintenance * Complete activity history 4. CLICK-TO-CALL We do NOT require VoIP, Twilio or a call centre system. From the customer’s profile, there should be a Call button. When using the CRM on a mobile phone, pressing it should initiate a normal call using the phone’s mobile network, similar to click-to-call functionality. After calling, the user should be able to record: * Answered / No answer * Interested / Not interested * Follow-up required * Notes * Next follow-up date/time 5. COMPLETE ACTIVITY TIMELINE This is very important. Every customer must have a chronological activity timeline. Important actions should automatically record date, time and user responsible, including: * Lead received * Meta source/campaign * WhatsApp sent * Calls/call outcomes * Notes * Follow-ups * Pipeline/status changes * Sale * Contract generated * Contract signed * Financing requested/approved/rejected * Installation assigned * Installation completed * Documents uploaded * Delivery document signed * Invoice generated * Commission generated * Warranty * Maintenance We want to be able to open a customer profile years later and see the complete history from the original Meta lead to the latest maintenance. 6. CONTRACTS & ELECTRONIC SIGNATURE * Generate contracts automatically using customer and sale information. * Generate PDF documents. * Electronic signature. * Store signed contracts automatically in the customer profile. * Record date/time of signature. * Customer receives a copy. Please specify whether electronic signature requires an external paid provider and its cost. 7. FINANCING We work with external finance companies. The system should allow us to record: * Finance company * Amount financed * Application date * Status * Approved/rejected * Approval date * Finance cost/commission * Relevant documents/notes 8. INSTALLATIONS & EXTERNAL INSTALLERS * Create installation/work orders. * Assign an external installer. * Installation date/time. * Customer address. * Product/equipment being installed. * Installer notes. * Upload photos/documents. * Mark installation completed. 9. DIGITAL DELIVERY / INSTALLATION DOCUMENT After installation: * Generate a digital installation/delivery document. * Customer can sign it. * Save signed document automatically. * Record installation/signature date and time. 10. INVOICING * Generate customer invoices. * PDF invoices. * Store invoices in customer profile. * Invoice numbering. * Paid/unpaid status. * Payment method. * Basic expense recording. The invoicing system must be designed appropriately for a Spanish business and allow future adaptation/integration if regulatory requirements change. 11. SALES COMMISSIONS The system should calculate and track salesperson commissions. We need to see: * Sale * Salesperson * Commission amount * Pending/approved/paid status * Payment date 12. WARRANTY & MAINTENANCE Each installed product should have: * Installation date * Warranty start/end date * Product/model * Serial number if applicable * Maintenance history * Next maintenance/filter-change date * Reminders/follow-up tasks 13. FINANCIAL DASHBOARD & PROFITABILITY We need a management dashboard showing: * Sales/revenue * Equipment/product costs * Installer costs * Sales commissions * Financing costs * Advertising spend * Refunds/cancellations * Other expenses * Gross margin * Estimated net/operating profit Profitability should be visible per sale and per month. Ideally, data can also be filtered by: * Date * Salesperson * Product * Location * Meta campaign/source The objective is to open the dashboard and quickly understand how much we sold, how much we spent and approximately how much profit the business generated. 14. USERS & PERMISSIONS Different user roles will be required, for example: * Administrator * Salesperson * Installer * Management Users should only access the information/functions appropriate to their role. 15. GENERAL REQUIREMENTS * Spanish-language interface * Modern, simple interface * Mobile