Backend & Payments Engineer — Delhi, India

I build the
whole thing

Full-stack engineer focused on backend systems, payment infrastructure, and production web applications. From APIs and databases to deployment — and occasionally the firmware.

150+
Production sites delivered
100+
Sites running my platform
4+ yrs
Shipping, PHP-first
01Flagship system

MyRentalPanel

SMM Platform · Lead Development

The engine behind 100+ live sites

A multi-tenant SMM / reseller platform I lead development on. It runs the full lifecycle — orders, provider routing, wallets, reconciliation, and admin workflows — reliably across 100+ independent websites.

STACK / PHP MySQL Redis Twig JS Multi-tenant Background jobs
The problem

Running an SMM / reseller business across many sites means managing orders, providers, and balances without letting a single number drift.

What I built

A multi-tenant engine: order lifecycle, provider routing, wallet accounting, and admin workflows — one codebase serving 100+ sites.

Hard parts
  • Provider reliability & retries
  • Atomic wallet accounting
  • Payment reconciliation
  • Multi-tenant at scale
Impact
  • 100+ live sites in production
  • Real customer usage daily
  • One engine, many tenants
02Selected systems

Production work

/01 Crypto · PaymentsZeenPe A custodial crypto payment gateway — wallets, deposits, and payouts with secure verification before any balance moves.PHP · Crypto · Webhooks · Reconciliation
/02 Tool · My ownSQL Data Transfer Migrates data between SQL databases even when column names or structures don't match — smart field mapping, any schema to any schema.PHP · MySQL · Schema mapping
/03 AI · RAGCompany Chatbots Retrieval-augmented assistants with fine-tuning — grounded in real company knowledge, not just prompts.Python · RAG · Fine-tuning · LLM
/04 E-commerceWrapVerse A full console-wrap & skin store — catalog, cart, checkout, and order tracking end to end.PHP · MySQL · Payments · E-comm
/05 Mobile · ToolingOTPDesk & AppyZeen OTPDesk — a virtual-number & OTP platform. AppyZeen — a Web2APK tool packaging web apps into Android builds.PHP · Web2APK · Android
/06 Security · ResearchResponsible Disclosure Identified security issues on publicly accessible university systems (AMU) and followed responsible-disclosure practice to help remediate them.SQLi Testing · Input Validation · OWASP
03Method

How I build things

01

Production first

I care about what happens after deploy — uptime, reconciliation, the edge case at 2am. Demos are easy; production is the real test.

02

Security by design

With payments and user data, security isn't bolted on later. Prepared statements, input validation, and safe auth from the first commit.

03

Own the whole system

Backend, APIs, database, deployment, infrastructure — I hold the full picture so nothing falls between the cracks.

04Expertise

Where I do my strongest work

CoreBackend & payments
PHPLaravelCodeIgniterMySQLRedisPayment APIsWebhooksReconciliationSystem DesignREST APIs
ExtendedProject-dependent
Node.jsPythonAI / RAGESP32ArduinoRaspberry PiC / C++Kafka
Infra & SecurityShip it, secure it
Linux / UbuntuVPS setupDeploymentWeb App SecuritySQLi Testing & PreventionXSS TestingBurp Suite
05About

Who's behind it

I'm Abu Saleh, a full-stack engineer from Delhi. PHP was my first language, and I never really left it.

Four years in, I work as a senior developer and freelancer — mostly on backend systems and payment integrations, with a habit of owning projects end to end. When a project needs AI, IoT, or infrastructure, I pick those up too.

Perfectionist and night owl — usually still debugging something when everyone else has gone to sleep. Off-screen, I'm into skincare, and I'd like to build my own product line one day.

Location
Delhi, India
Focus
Backend & payments, PHP-first
Experience
4+ years shipping
Also
NASA Science 101 · skincare
06Contact

Got something
complicated
to build?