Case study · Backend, APIs & admin panels

Plegium: a personal-safety alarm platform

Backend services, APIs and admin panels I build for Plegium, a personal-safety app that raises an alarm from the phone or a paired device, calls and texts the user’s emergency contacts, and shares their live location.

Python
FastAPI
Go
Next.js
React
MySQL
PostgreSQL
DynamoDB
Firebase
AWS
Docker
Twilio

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One press. Every contact alerted.

Plegium is a Swedish personal-safety company. Since October 2024 I’ve worked on its platform with my team at Zennaxx Technology: Python (FastAPI) microservices for calls, SMS, one-time passwords, registration, IoT devices and alarm partners, a Go subscription API, and Next.js admin panels. When an alarm starts, the services call and text the user’s emergency contacts through Twilio, retry unanswered calls, and show the user’s live location until the alarm is turned off.

How it works

Alarm, escalation, live location.

The services run in Docker on AWS, with Aurora MySQL and PostgreSQL, SQS, S3 and DynamoDB. Admin panels manage users, groups, devices, alarms, partners and subscriptions, kept in sync with Chargebee, Recharge and Seal.

Call & SMS escalation

Contacts get an SMS with a live-location link and a Twilio call. Unanswered calls are retried after 30 seconds and again after 3 minutes, through an SQS delay queue.

Live location

While the alarm is active, contacts follow the user on a Next.js tracking page with Google Maps. In 2026 I moved location storage from Firebase to PostgreSQL.

Devices & integrations

Alarms also come from Bluetooth pepper sprays and keychains and from an IoT alarm managed through AVSystem Coiote, with Agora live audio, Noonlight dispatch and App Attest / Play Integrity checks.