Usapp
A live conversation: end-to-end encrypted, with delivery and seen receipts. Built solo across the mobile client, the microservices behind it, and the servers it runs on.
captured 2026-09-08 · usapp.ph
usapp.ph ↗~/john-filhmar-ola $ ./introduce --brief
Lead IT · Full-Stack Engineer · DevSecOps & Infrastructure
I build systems end to end, from first commit to production operation.
most recently: Lead IT @ YouCode Technologies · systems shipped: 5+ · status: open to work
$ ./init --profile john.filhmar.ola
▸ loading modules …
full-stack ✓ microservices ✓ DevSecOps ✓ infra ✓ security ✓
▸ most recently: Lead IT @ YouCode Technologies
▸ owning systems end to end, first commit to production
$ ready, scroll, or press ⌘K
I own systems from first commit to production.
I'm a Lead IT and full-stack engineer, most recently at YouCode Technologies, where I owned multiple production systems end to end: architecture, development, automated testing, CI/CD, and on-premise infrastructure. I was promoted to lead within my first year.
My favorite work spans the whole stack. I was the sole developer of Usapp, a secure real-time messaging platform built from scratch across mobile, distributed microservices, deployment pipeline and production servers, now the notification backbone for the company's entire product suite.
I care about the unglamorous parts too: security scanning in CI, hardened containers, monitoring, and incident diagnosis at 3 a.m. This site is part of the evidence: every section, color and sentence is editable config, no code changes.
$ whoami
john filhmar ola: lead IT · full-stack · DevSecOps
$ cat focus.txt
production systems · infrastructure ownership · shift-left security
$ cat philosophy.txt
"Build it, secure it, ship it, run it, end to end."
$ status
Lead IT @ YouCode Technologies · Dasmariñas, PH (UTC+8)
Across the stack. Deep where it counts.
Typed everywhere, from web to firmware.
Interfaces that feel instant.
Distributed services that stay up under load.
Schema-first, cached where it matters.
Automated from commit to production.
On-premise servers, provisioned and hardened by hand.
Shift-left, supply-chain aware.
Observability and load testing before it breaks.
Where software meets metal.
Full-stack ownership, teams that ship.
Work that shipped.
Secure real-time messaging platform: the notification backbone for an entire product suite.
▲ Live · the notification backbone for the company's entire product suite · positioned as a super-app foundation.
problemThe company's product suite needed one secure, real-time channel for messaging and push notifications instead of fragmented per-app integrations and an SMS dependency.
my roleSole developer & architect: mobile client, distributed backend microservices, deployment pipeline, and production server operations, all built and run single-handedly.
Multi-branch automotive service management, self-hosted and self-operated.
▲ Live in production on a self-managed VPS · four-workflow CI/CD · layered security scanning · ongoing feature development.
problemMulti-branch automotive service operations needed real-time monitoring and reliable daily transaction reporting, on infrastructure owned and operated end to end, not rented as a black box.
my roleSole developer, owner & maintainer: application, DevSecOps pipeline, and a self-provisioned VPS I secure, manage and operate myself.
Privacy-first Android budgeting that tracks spending from your transaction notifications.
▲ In development · free-to-use · privacy-by-design · tracking derived from transaction push notifications.
problemManual expense logging is high-friction and most budgeting apps expose sensitive financial data. Users needed private tracking that updates itself.
my roleSole developer: Android app, encryption model, and notification-derived transaction tracking.
Per-client HR platform covering the full employee lifecycle: hiring to payroll to compliance.
▲ In production as a per-client system for government and private-sector organisations. Architecture, structure and stack withheld under NDA.
problemOrganisations, both government and private, needed one system to run their entire HR operation, delivered as an isolated per-client instance whose data never mixes with any other client's.
my roleSole developer: built the product end to end at YouCode Technologies.
key decisionsCovers the full employee lifecycle: onboarding, time & attendance, leave, payroll, performance, recruitment, training, records and compliance. Client-specific behaviour (branding, leave policies, single sign-on) is configured by admins in-app, so one product serves many organisations with no code changes. Access is governed by a permission model tied to each organisation's own hierarchy: a person can only ever delegate a subset of the access they hold. Shipped as a self-contained, isolated deployment per client: no shared multi-client data store.
White-label super-app that lets a city run its own branded resident app: three cities live.
▲ Live for three cities: MyDasma (Dasmariñas), MySorsogon (Sorsogon City) and MyLegazpi (Legazpi), with new cities added by configuration alone. Internal architecture and stack withheld under NDA.
problemEvery local government wanted its own citizen app and admin consoles, but building one per city doesn't scale. The design mandate: every per-city difference is data, never code.
my roleSole developer: resident mobile app, the city and platform web consoles, and the backend, end to end.
key decisionsOne platform serves many cities: a new city is onboarded through configuration and content, not a code branch. Resident app: government services, 311 issue reporting, emergency SOS, news, tourism, transport, evacuation centres and a digital ID, usable offline. A city console for staff (content, maps, dispatch, alerts, submission queues) plus a separate platform console for operating the whole fleet of cities. Live emergency dispatch on a real-time command map, and targeted alerts with per-recipient delivery tracking.
An LMS that keeps working with no signal: offline exams, lessons and verifiable credentials.
▲ Built for large, distributed organisations with thousands of concurrent learners on unreliable networks. Implementation details withheld under NDA.
problemLarge, distributed organisations needed to train and test thousands of learners on modest phones over unreliable networks, where a dropped connection must never lose a learner's work.
my roleSole developer: built the platform end to end at YouCode Technologies.
key decisionsComputer-based testing runs entirely on the device and syncs answers back when a connection returns: nothing is lost to a dropped signal. Offline course player for reading and studying lessons, including video, with no connection. Verifiable micro-credentials anyone can check through a public verification portal. Bulk onboarding of thousands of learners processed in the background, so large imports never stall or time out.
AI-native Kanban: automatic work estimation, daily management reports, and a native interface for AI agents.
▲ In use for AI-assisted team workflows: the team tracks YouFlow's own development inside YouFlow. Architecture, structure and stack withheld under NDA.
problemOrdinary Kanban tools track where work sits but not who produced how much, force managers to assemble end-of-day updates by hand, and give AI assistants no safe, permissioned way to participate as real team members.
my roleSole developer: built the platform end to end at YouCode Technologies.
key decisionsAI-suggested story-point estimates and due dates on new cards, with human confirmation: only confirmed estimates count toward reporting, so the numbers stay trustworthy. Automated end-of-day reports: a scheduled job compiles each workspace's finished work and delivers it to management over SMS or email at a set local time. A native Model Context Protocol (MCP) interface lets AI assistants read and drive the board as an authenticated team member, with exactly that user's permissions. External intake tokens let other systems post bug reports straight onto a board; a per-workspace role hierarchy governs who can do what.
Game-based learning platform for General Biology: teachers host quiz rooms, students join with a code.
▲ Live at genesys.filhmar.online · deployed for a quasi-experimental Grade-12 STEM study (Puerto Galera NHS, AY 2025–2026).
problemLecture-driven biology instruction leaves Filipino senior-high STEM students disengaged and struggling to retain complex topics like genetics, evolution and homeostasis.
my roleSole developer: full-stack platform (teacher dashboard, student quiz engine, backend and deployment), built for a Grade-12 research study.
key decisionsRoom-based model: teachers build quizzes and host private rooms; students join with a 6-character code, no account required. Flexible assessment builder with six question types, a reusable question bank, and auto-expiring rooms. Resilient student quiz engine: answers auto-save to the device with an offline retry queue (exponential backoff), so a dropped connection never loses work. Real-time room monitoring plus analytics exportable to Excel and PDF: class distribution, per-question analysis, and individual reports.
Self-hosted edge server linking on-site access-control and camera hardware to the cloud.
problemA facility's turnstiles and face-recognition cameras each spoke different protocols and needed a reliable, offline-tolerant link to the cloud platform, without opening any inbound firewall holes.
my roleSole developer: designed and built the edge service and its web admin console end to end.
key decisionsOne deployable service per site hosts every hardware family behind a common adapter, replacing separate single-purpose bridges. Accepts scan events from turnstiles and face-recognition cameras, decides entry/exit direction, and forwards them to the cloud durably. Keeps operating while the cloud is unreachable, then replays everything it buffered: nothing is lost. All cloud traffic is outbound-initiated, so sites need no inbound firewall openings; ships its own admin console and live video wall.
Digital health records and scheduling for rural clinics.
problemRural clinics relied on paper records and manual scheduling, limiting record accessibility and efficiency for underserved communities.
my roleDeveloper: patient records and appointment management built for low-resource clinic environments.
key decisionsDigital patient records replacing paper-based systems. Appointment scheduling and management. Built for low-resource clinic environments.
IoT flood early-warning with sirens, warning lights, and SMS alerts.
problemFlood-prone communities needed early warning that conveys not just that water crossed a threshold, but how fast it is rising, so residents can judge how quickly conditions are worsening.
my roleSole developer: sensors, embedded firmware, and multi-channel alerting.
key decisionsMulti-channel alerting: audible sirens, warning lights, and GSM SMS dispatch. Tracks both water level and rate of rise per monitored area. Designed for community-level deployment in flood-prone areas.
Systems caught in the act of working.
Claims are cheap. These are captures of the real products doing the job they were built for, each one linked to an address you can open yourself.
$ ls -la ~/proof/ # 4 artifacts
A live conversation: end-to-end encrypted, with delivery and seen receipts. Built solo across the mobile client, the microservices behind it, and the servers it runs on.
captured 2026-09-08 · usapp.ph
usapp.ph ↗One bank notification becoming a ledger entry: parsed into amount, direction, merchant and category, then committed and reflected in what is safe to spend. All of it on the device.
captured 2026-09-08 · peraplano.filhmar.online
peraplano.filhmar.online ↗A quiz room mid-round, timer counting down and score tracking correct, wrong and missed. Written to the Philippine K-12 General Biology curriculum.
captured 2026-09-08 · genesys.filhmar.online
genesys.filhmar.online ↗Motor parts inventory and service booking, running on a VPS provisioned, secured and deployed end to end. The working views sit behind a sign-in, so this is the public storefront.
captured 2026-09-06 · jms-e-talyer.shop
jms-e-talyer.shop ↗Building and operating production systems.
Jul 2025 – Sep 2026
YouCode Technologies
Feb 2025 – May 2025
Ynnovision Enterprise Solutions
Where the fundamentals came from.
2021 – 2025
Mindoro State University
Graduated. Shifted from AB English (2019 – 2021) to BSIT.
Jul 2024 – Oct 2024
BCRV Tech-Voc, Inc.
TESDA-accredited technical-vocational qualification taken alongside the degree, in Calapan City, Oriental Mindoro.
Ask me anything.
A small demo of how I build AI features: this assistant answers questions about my work using a structured knowledge base, with intent matching, streamed responses and graceful fallbacks.
▸ live mode: answers are generated by an LLM grounded in a curated knowledge base · it can make mistakes, so verify anything important
try:
assistant ▸
Let's build something.
If you're hiring for full-stack, DevSecOps or infrastructure work, or you just want a second opinion on an architecture or a production setup, my inbox is open. I reply within 24 hours.
olajohnfilhmar@gmail.com$ ./send-message # sends your message straight to my inbox