Call-Out

Client Info:

Call-Out (Coas Solutions product) · First client: 25Seven Assist
Project Handover:

Live since 30 September, 2026.
Services:

Web & Mobile App Development, Backend API, Sage Accounting Integration, Online Payments, UI/UX Design.
Platform:

Web, Android & iOS (.NET 9, React, Azure)

From Customer Call to Paid Invoice, In One System

Plumbers, electricians and other trades lose hours to phone calls, WhatsApp threads, paper job cards and retyping invoices into accounting software. Call-Out replaces that chaos with one connected workflow: the customer books online, the dispatcher assigns the right technician, the technician completes the job on their phone, and the invoice lands in Sage automatically.

Each business gets its own branded address, its own staff and its own data, with plans from Core to Enterprise so the platform grows with the client.

Overview:

Online booking page and WhatsApp intake, with emergency call-outs flagged instantly.
Dispatcher dashboard with live map and suggested technician by area, skill and workload.
Offline-capable technician app: arrival updates, before/after photos, parts, labour and customer signature.
Quotes and tax invoices posted to Sage Business Cloud Accounting, with card and EFT payment links.

Challenge:

Keeping every client's data isolated in one multi-tenant platform, with row-level security.
Integrating reliably with Sage One SA's rate limits, OAuth sign-in and retries.
Giving technicians a fast app that still works with poor signal on site.
Meeting enterprise needs: two-step sign-in, audit log, approvals, branches and SSO.

Solution And Results:

Call-Out is built on a .NET 9 API and a React front end, hosted on Azure with Key Vault secrets, SQL Server, audit logging and an Android app. It is covered by more than 600 automated tests.

Jobs flow from booking to payment without double capture of invoices.
Customers are kept informed by SMS, WhatsApp and email at every step.
Business owners see status, workload and payments on a single dashboard.
Enterprise features include approvals, response-time targets, branches, SSO, API keys and scheduled reports.