A workforce platform for UK security companies. S4 replaces paper sign-in books with verified check-in, live tracking, patrol records and timesheets, across a company dashboard and a guard mobile app.
S4 is built for security companies that run their own guard workforce. A company posts jobs, reviews applicants against their SIA status, and fills shifts, while guards use the S4 mobile app to find work, apply and check in on site.
The core idea is server-authoritative proof of presence. A guard checks in by scanning a site code that rotates, from inside a geofence drawn around the site, so a check-in can't be faked from a photo of the code or from somewhere else. From there, S4 records live location, patrol checkpoints and time on site, and turns it into timesheets.
Every action that matters is written to a hash-chained, append-only audit trail, and each company's data is isolated from every other company's. When a client asks whether a site was covered, the answer comes from the record.
Read the full article: Security Guard Management Software: How S4 Replaces Paper Sign-In Books →
Post jobs with the site, sector, shift window, pay rate and headcount, and track fill rate from the dashboard.
Review each applicant with their SIA licence status visible, then approve or reject.
Guards scan a rotating site code from inside the site boundary, so check-ins can't be spoofed.
See where on-duty guards are while a shift is running.
Define checkpoints and patrol schedules, and see each one confirmed as it happens.
Hours come from recorded check-ins and time on site, not from paper sign-in books.
When a guard drops out, S4 matches and offers the shift to suitable replacements.
An optional biometric sign-in challenge confirms the right guard is on the account.
A hash-chained, append-only log of every state-changing action, scoped per company.
The company creates a job for a site with the shift window, pay and number of guards needed.
Guards apply from the app; the company reviews SIA status and approves the right people.
The guard scans the rotating site code from inside the geofence to start the shift.
Live location and patrol checkpoints are recorded while the shift runs.
Time on site feeds the timesheet, and the audit trail keeps a tamper-evident record.
S4 is a NestJS API on PostgreSQL with PostGIS for geofencing, a React and TypeScript company dashboard, and a Flutter guard app for Android and iOS. Row-level security keeps each company's data separate at the database, not only in application code.
It's the same team behind our application development and CRM development work for clients. If you need a platform like this for your own operation, talk to us.
UK security companies that manage their own guards and want verified check-in, patrol records and timesheets in place of paper sign-in books.
A guard has to scan a site code that rotates, while their device is inside the geofence drawn around the site. The check is made on the server, so it can't be passed with a screenshot or from another location.
Applicants are shown with their SIA licence status so companies can review it before approving a guard for a job.
S4 is for a security company running its own workforce. Guardlane is a marketplace where companies post cover shifts for independent officers to pick up.
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View product →Explore the platform, or talk to us about building something similar for your operation.
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