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Faiz Mohammad Hafidza

Faiz wearing sunglasses and a grey sleeveless shirt, looking upward

I design and build the backend behind payments, battery swapping and biometric attendance, mostly in Go.

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  • Fintech
  • E-wallet
  • Consumer finance
  • IoT
  • Telecom
  • Biometric attendance
  • Recruitment
  • Retail
  • Asset management
  • Subscriptions
  • Go
  • PostgreSQL
  • Redis
  • Apache Kafka
  • Node.js
  • Express
  • PHP
  • Laravel
  • Yii2
  • CodeIgniter
  • TypeScript
  • React
  • Next.js
  • MySQL
  • MinIO
  • Elasticsearch
  • Kibana
  • Centrifugo
  • Traccar
  • Swagger
  • Ruby on Rails

Overview

Since 2021 I have been writing backend services at a software house, for clients in fintech, e-wallets, IoT, telecom and biometrics. Most of it is Go on PostgreSQL and Redis, with PHP and Node.js along the way. Lately I also design systems before they are built: C4 diagrams, database structures and server sizing.

Role
Software Engineer at PT. Code Development Indonesia, since May 2021
Now
Solution architect for Adira Finance Ad1Seller 2.0, payment APIs for Duwit
Stack
Go, PostgreSQL, Redis
Based in
Cimahi, West Java, Indonesia

What I work on

  • Payment APIs

    BI-SNAP balance inquiry, debit, status and cancel endpoints for partner wallets, and Midtrans Snap with secure webhook handling.

    • Duwit
    • Gesit Volta
    • VOLTA

  • Consistency under load

    Pessimistic locking against race conditions, per-user rate limits in Redis, and request timeouts that keep transactions consistent when a downstream service is slow.

    • MCASH
    • Duwit

  • Devices and telemetry

    Traccar as the IoT gateway, middleware that turns raw device data into application-ready records, and sync services for battery cabinets.

    • Gesit Volta
    • VOLTA

  • Database design

    Table structures and relationships, migrations that stay backward compatible, and query tuning for transaction-heavy tables.

    • PVR
    • Duwit
    • Adira

  • Architecture and review

    C4 models, capacity planning and server sizing, solution design for vendor teams, and code review across merge requests.

    • Gesit Volta
    • Adira
    • Duwit

Featured projects

  1. VOLTA

    SGB & SEMOLIS

    Sep 2021 - now

    IoT, battery swap, electric motorcycle

    Client: MCASH

    • SGB: the swap and charging API behind VOLTA.
    • SEMOLIS: e-motorcycle and battery rent-to-own.
    • Middleware: Traccar telemetry into PostgreSQL.
    • Go
    • PostgreSQL
    • PHP
    • Yii2
    • MySQL
    • Redis
    • MinIO
    1. Cabinet IoT (hex status)
    2. Traccar (Java), MySQL
    3. Traccar middleware (semaphore ID mapping)
    4. PostgreSQL
    5. SGB API (swap, SCB, Midtrans)
    6. SEMOLIS and VOLTA, mobile and web dashboard
    Simplified flow

  2. Duwit

    Partner Wallet

    Jun 2026 - now

    Fintech, e-wallet

    • Core payment APIs on BI-SNAP: balance inquiry, debit payment, debit status and debit cancel.
    • Per-user rate limiting in Redis and a timeout middleware that protect payment flows when downstream calls are slow.
    • Automated partner reconciliation: report files uploaded to storage and emailed to each partner.
    • Go
    • PostgreSQL
    • Redis
    1. Partner platform
    2. Rate limit (Redis)
    3. Request timeout
    4. BI-SNAP API (Go)
    5. Wallet, consumer and partner data (PostgreSQL)
    Simplified flow

  3. Telkomsel

    SiGeulis / Gesit Volta

    Feb 2025 - Mar 2026

    Telecom, IoT

    • REST APIs for the web CMS and Telkomsel's mini-app (TCMPP).
    • Traccar configured as the IoT gateway, with middleware that normalizes device telemetry into application-ready data.
    • Midtrans Snap payments with secure webhooks, tracing in Elasticsearch and Kibana, C4 architecture and server sizing.
    • Go
    • PostgreSQL
    • Redis
    • MinIO
    • Elasticsearch
    • Traccar
    1. IoT devices
    2. Traccar gateway
    3. Telemetry middleware
    4. API (Go)
    5. PostgreSQL, Redis, MinIO
    Simplified flow

  4. PVR

    Palm Vein Reader

    May 2026 - Jul 2026

    Biometric attendance

    • Shift rule management per company: create, edit and duplicate rules.
    • Validation that blocks conflicting rules across validity periods, departments, users and scan windows.
    • Unit tests with 80%+ code coverage, plus an Agent.md guide for AI-assisted development.
    • Go
    • PostgreSQL
    1. Palm vein scanner
    2. Attendance API (Go)
    3. Shift rule validation
    4. PostgreSQL
    Simplified flow

  5. MCASH

    Konsolidasi Keuangan

    Oct 2023 - May 2024

    Fintech

    • Backend API for a financial consolidation product.
    • Service workers for Excel import and export and for validating accountant balances.
    • Race conditions in the API handled with pessimistic concurrency control.
    • Go
    • PostgreSQL
    • Kafka
    • Centrifugo
    • ZooKeeper
    1. Excel upload
    2. Import worker
    3. Kafka
    4. Balance validation
    5. PostgreSQL
    Simplified flow

Experience

All the work below was done through PT. Code Development Indonesia, a software house where I have worked as a Software Engineer since May 2021.

  1. Aug 2026 - now

    Adira Finance, Ad1Seller 2.0 Revamp

    Solution architect for a vendor-built revamp: business requirements to system design and database structure.

  2. Jun 2026 - now

    Duwit, Partner Wallet

    BI-SNAP payment APIs, rate limiting and partner reconciliation.

  3. May 2026 - Jul 2026

    PVR, Palm Vein Reader

    Shift rules and attendance backend, 80%+ test coverage.

  4. Dec 2025 - Mar 2026

    Chat Idol

    WhatsApp content delivery by subscription, with stock alerts for admins.

  5. Feb 2025 - Mar 2026

    Telkomsel, SiGeulis / Gesit Volta

    APIs for the CMS and Telkomsel mini-app, IoT gateway and payments.

  6. Sep 2024 - Nov 2025

    FastMart

    Express.js API maintenance and a better cart upsert flow using Redis SMQ.

  7. Feb 2024 - May 2025

    BAF Scan Barcode Enhancement

    Lead backend: stock opname APIs, MinIO storage and Redis login sessions.

  8. Oct 2023 - May 2024

    MCASH, Konsolidasi Keuangan

    Backend API and workers for Excel import/export and balance validation.

  9. Oct 2022 - Mar 2024

    Karir.com

    Backend APIs for Karir.com, its revamp and Karir TechnoFair; Erika recruiter dashboard on Rails.

  10. Sep 2021 - now

    VOLTA, SGB and SEMOLIS

    Battery-swap APIs, cabinet and battery sync, reporting; Yii2 dashboard, cron and daemon services.

Contact

For backend roles or projects in fintech, payments, IoT or telecom, email is the fastest way to reach me.

faizmohhafidza@gmail.com
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© 2026 Faiz Mohammad Hafidza