Siddhant Kumar · Senior Mobile Engineer Deep in iOS. Fluent across mobile.

I'm a senior mobile engineer at INDmoney with seven years of shipping apps across travel, e-commerce and fintech. Native iOS is home — Swift, SwiftUI, UIKit — and I build for Android and Flutter too, plus the Node.js services behind them when a product needs one.

  • iOS · primary
  • Android
  • Flutter
  • Node.js backend
View projects Get in touch

Experience

  1. May 2025 — NowGurugram

    INDmoney · Senior Software Engineer, iOS

    Platform team → Stocks team

    • Built a resilient networking layer over URLSession — mTLS with certificate pinning, IPv6, retry/backoff and failover — lifting API success from 93% to 95% and cutting P90/P99 latency.
    • Built a real-time socket system on NATS with a WebSocket fallback and global position syncing, so trade status updates land instantly.
    • Re-engineered the US Stocks trade engine with complex order types and execution fixes — order rejections down from 3% to 0.5%.
    • Brought Brotli compression to document and JS formula delivery for 60%+ smaller payloads, fast even on 3G/4G.
    • Built hot reload for JS-driven pages, taking the dev loop from minutes to under 10 seconds.
  2. Mar 2022 — Apr 2025New Delhi

    TravClan · Lead Engineer, iOS

    • Led a team of 4 engineers across iOS and Flutter, shipping several products — including Ontrip, a standalone traveller app in Flutter.
    • Designed the VIPER architecture with dependency injection and SOLID principles, so features could be built in parallel.
    • Built the core travel and payment modules — flights, hotels, packages and payments — with booking changes, cancellations and support tickets.
    • Owned release health: a 99% crash-free user rate, App Store submissions, staged rollouts and incident response.
    • Set up CI/CD for iOS and Flutter on GitHub Actions, with multi-environment configs and SwiftLint checks.
  3. Jun 2019 — Mar 2022Noida

    Webkul · iOS Developer

    • Designed and shipped 10+ iOS apps for Magento 2, OpenCart, PrestaShop and CS-Cart, from architecture to App Store.
    • Built a reusable component library used across every client project.
    • Led the move from Swift 2/3/4 to Swift 5, cutting crashes across live apps.
  4. 2015 — 2019Noida

    B.Tech, Computer Science · Greater Noida Institute of Technology

Projects

Tools I build and run myself, apps I've shipped with teams, and a few things I made for fun. Most of the side projects are named after Norse myths and the wizarding world.

Built and run by me

Live, open source and in use.

Web app + LAN hub · v2.0.0Live

Bifrost

A private hub for every device on your Wi-Fi.

Bifrost turns one machine on your network into a hub for every phone, tablet and laptop in the house — no cloud, no accounts. Send files between devices, share a clipboard, and open a full workbench of developer tools. The browser tools are live on the web, too.

  • Files and clipboard sync across devices, live over SSE
  • Editors for JSON, YAML, XML/plist, Markdown and JavaScript, a JSON diff, and 15 everyday utilities
  • A CLI, OpenAPI docs and an optional Grafana observability stack
  • Runs natively on a Mac, or on a Raspberry Pi with Docker

Node.js · TypeScript · Fastify · React · SQLite · Docker

Open the live tools GitHub
Bifrost home screen with Send files, Receive files and the Hermes shared clipboard Sending files to Bifrost from a phone
Self-hosted APILive

Mock API

Make your API fail — on purpose.

Upload any JSON, get a URL, then make it slow, flaky or wrong with one query parameter — delays, forced errors, random failures and scripted retry sequences. Test loading states and error screens before your users find them.

Plain Node.js · zero runtime deps · 202 tests

Try it live
Sonorus reading a highlighted Wikipedia paragraph aloud with its floating pill player
Browser extension · v3.2.0Published

Sonorus

Select any text. Hear it instantly.

Text-to-speech with a floating, draggable pill player — your voice, your speed. Works on PDFs, embedded frames and web components, adds a right-click "Read aloud", and runs offline with no account and no data collected.

Chrome · Firefox · Edge · Brave · Safari

Chrome Web Store GitHub
macOS CLIReleased

xcodeproj_audit

A health check for Xcode projects.

Finds missing and orphaned files, empty sources, code stats by file type, SPM dependencies and build settings — or all of it in one dashboard report. One-line install, universal binary, built-in updates.

Swift · XcodeProj · ArgumentParser

GitHub

Shipped with teams

Production apps from my day jobs.

INDmoney · iOS

INDmoney app

Trade screens for US and Indian stocks, with live order updates over real-time sockets and a networking layer built for reliability.

Swift · SwiftUI · mTLS

App Store
TravClan · iOS

TravClan app

The main iOS app — flights, hotels, packages and payments, with booking changes, cancellations and support tickets.

Swift · VIPER

App Store
TravClan · Flutter

Ontrip

TravClan's traveller app, built from the ground up — itineraries, vouchers and e-tickets, plus chat with support for agent-booked trips.

Flutter · Dart

App Store
Webkul · iOS

Commerce app suite

Storefront apps for Magento 2, OpenCart, PrestaShop and CS-Cart, built on a shared component library.

Swift · E-commerce

Just for fun

Experiments and learning projects — built because I was curious.

Offline-first Task Board

An iOS kanban board that works with no network and syncs later — Core Data with an outbox, fractional-index reordering and an optional Firestore backend.

Swift · Core Data · Firebase

GitHub

wireload

A YAML-driven load test that records the exact bytes each API streams off the wire — never decoded — so you see real compressed payload sizes, not guesses.

Python · Locust · YAML

GitHub

NewsApp

A news reader on NewsAPI with keyword and voice search, headline categories, source browsing and pagination — built with MVVM and coordinators.

Swift · UIKit · Alamofire

GitHub

SSL Pinning in Swift

A walkthrough of public-key and certificate pinning with Alamofire 5 — building a SecKey from the certificate and wiring both approaches.

Swift · Alamofire · Security

GitHub

Mix-Or-Match

A Halloween memory game in the browser — flip the cards, find every pair of bats, ghosts and pumpkins before the 100-second clock runs out.

Browser game · JavaScript

Play it

Toolbox

Everything I've used to build, ship and run the work above — at my day jobs and in my own projects.

iOS

Native apps, my home turf

  • SwiftLanguage
  • SwiftUIDeclarative UI
  • UIKitUI framework
  • CombineReactive streams
  • async/awaitConcurrency · GCD
  • Core DataPersistence
  • Objective-CLegacy code
  • Alamofire, used in my own projectsNetworking library

Apple tooling

Build, profile, distribute

  • XcodeIDE
  • InstrumentsProfiling
  • SPMSwift packages
  • CocoaPodsDependencies
  • App Store ConnectDistribution
  • TestFlightBeta testing
  • XcodeProj, used in my own projectsProject parsing
  • ArgumentParser, used in my own projectsSwift CLIs

Android & Flutter

When the product needs both platforms

  • FlutterCross-platform UI
  • DartLanguage
  • AndroidPlatform

Architecture

Structure sized to the problem

  • MVVMUI pattern
  • VIPERModular pattern
  • Clean ArchLayering
  • DI · SOLIDDesign principles
  • Coordinator, used in my own projectsNavigation
  • Outbox, used in my own projectsOffline-first sync

Backend

The services behind the app

  • Node.js, used in my own projectsRuntime
  • TypeScript, used in my own projectsTyped JavaScript
  • Fastify, used in my own projectsWeb framework
  • Zod, used in my own projectsValidation
  • Python, used in my own projectsScripting
  • ShellScripting

Data & APIs

Storing and describing data

  • RESTAPI style
  • ProtobufSerialization
  • SQLite, used in my own projectsDatabase
  • Drizzle, used in my own projectsORM · migrations
  • OpenAPI, used in my own projectsAPI docs · Swagger
  • Firestore, used in my own projectsCloud database

Networking & real-time

Fast, secure, resilient

  • URLSessionHTTP client
  • WebSocketReal-time
  • NATSMessaging
  • mTLSCert pinning
  • BrotliCompression
  • SSE, used in my own projectsServer push
  • mDNS, used in my own projectsLocal discovery

Web & extensions

In the browser

  • JavaScriptLanguage
  • React, used in my own projectsUI library
  • Vite, used in my own projectsBuild tool
  • CodeMirror, used in my own projectsCode editors
  • Manifest V3, used in my own projectsBrowser extensions
  • Web Speech, used in my own projectsText-to-speech

Testing & quality

Catch it before users do

  • XCTestiOS tests
  • Swift TestingiOS tests
  • SwiftLintLinting
  • Vitest, used in my own projectsJS unit tests
  • Playwright, used in my own projectsEnd-to-end
  • Locust, used in my own projectsLoad testing
  • ESLint, used in my own projectsJS linting

CI/CD & workflow

Every change, checked and shipped

  • GitHub ActionsCI/CD
  • GitVersion control
  • Husky, used in my own projectsGit hooks
  • Commitlint, used in my own projectsCommit rules
  • Prettier, used in my own projectsFormatting

Infra & hosting

Where my own services run

  • Docker, used in my own projectsContainers
  • Compose, used in my own projectsMulti-service stacks
  • nginx, used in my own projectsWeb server
  • PM2, used in my own projectsProcess manager
  • launchd, used in my own projectsmacOS services
  • VPS, used in my own projectsSelf-hosting

Observability

Knowing what production is doing

  • CrashlyticsCrash reports
  • FirebaseApp platform
  • New RelicPerformance (APM)
  • MixpanelProduct analytics
  • Grafana, used in my own projectsDashboards · Loki
  • Prometheus, used in my own projectsMetrics
  • OpenTelemetry, used in my own projectsTracing · Tempo

How I work

  1. 01

    Own it end to end

    From the first line of code through QA, release, and the monitoring and scaling after launch.

  2. 02

    Architecture sized to the problem

    VIPER, MVVM or Clean Architecture — picked for the team and the codebase, without ceremony a three-screen app doesn't need.

  3. 03

    Networks that hold up

    mTLS, retry and failover, real-time channels with a fallback, offline-first sync and payloads cut down to size.

  4. 04

    Ship with confidence

    CI/CD on every change, crash reporting in production, and tests that run against the real thing.

Building a mobile app — or the backend behind it?

I work across the whole mobile stack and the services that feed it. Open to senior and lead mobile roles, and always happy to talk shop.

Mobile

  • Native iOS apps in Swift, SwiftUI and UIKit
  • Android and Flutter when one product needs both platforms
  • Networking, real-time data and offline-first sync
  • Architecture, performance and release health

Backend

  • APIs in Node.js and TypeScript, with OpenAPI docs
  • Real-time over WebSocket, SSE and NATS
  • Self-hosting with Docker, plus observability with Grafana
  • End-to-end and load testing before anything ships
[email protected] LinkedIn GitHub X