Senior iOS engineer. Berlin.

I build iOS products that make complexity disappear.

I’m Aamir, a Senior Software Engineer in Berlin. I build the iOS systems behind everyday experiences at Wolt, DoorDash, and Deliveroo.

Product engineering
Platform architecture
Payments at scale

Get in touch Explore the work

Aamir Suhial Mir — 10+ years in engineering · Based in Berlin

Across three global brands.

Wolt

DoorDash

Deliveroo

One shared foundation

Apps

Out in the world.

Apps I’ve helped build, from the next meal to a doctor’s next decision.

M-sense

Migraine tracking & therapy companion (Newsenselab).

Delisted

Featured Work

Behind one tap.

A simple checkout depends on many systems working together. This is where I go deepest.

Payments & FinTech

Three brands.
One foundation.

I build the shared iOS payments layer for Wolt, DoorDash, and Deliveroo. Each brand keeps its own experience, with one SDK handling the complexity underneath.

30+

Payment methods

Providers

Follow a payment

Wolt

DoorDash

Deliveroo

Shared payments SDKSwift · iOS

AuthenticationPayment methodsProviders

Independent experiences. Shared engineering.

Provider integration

I designed protocol boundaries that account for differences between payment providers. Dependency injection keeps those integrations testable and lets each app use the shared SDK without a separate fork.

Clear contracts. Testable integrations.

Interface & interaction craft

I’ve shipped server-driven UI, custom bottom sheets, and motion tied to real design-system tokens. Entry and exit timings are tested separately because the details are visible in everyday use.

Server-driven UI. Motion with a purpose.

Performance & reliability

I migrated payment modules to Swift 6 strict concurrency, added caching on hot paths, and used leak detection and distributed traces to find where time and memory were actually going.

Swift 6 · Memory diagnostics · Tracing

Testing & automation

I integrated Maestro end-to-end tests into CI across three brands. Characterization tests protect existing behavior during refactors, and investigating flaky tests keeps the suite useful.

Maestro · Characterization tests · CI

Platform & design systems

I work daily in Prism and Mosaic, large monorepos, Bazel and SPM builds, and staged feature rollouts. The platform work is successful when product teams can make changes without learning every internal detail first.

Prism & Mosaic · Bazel & SPM

Inside a payment · Demo

From tap to approved.

CHECKOUT

•••• 4242VISA

€42.00 Pay

3D SecureEnter bank PIN

Identity verified

Approved.€42.00

Your app

✓

PSP

✓

Visa network

✓3DS

Card issuer

Pay
Verify
Authorize

A secure checkout.

About this demo

The payment request first travels through the PSP and card network to the issuing bank. When required, the issuer sends a 3D Secure challenge to the customer. After the bank PIN is entered and verified, the issuer authorizes the payment and the approval returns along the payment route. Merchant servers and acquiring services are grouped into the PSP. Authorization is separate from capture and settlement.

Recognition

In their words

“We are delighted to work with such a forward-thinking group of people from Wolt to transform the way people check out. Special thank yous to the amazing Team Wolt: … Aamir Suhial …”

Emma Pitt, Revolut

On the launch of Revolut Pay across Wolt • 20+ European markets

Live in

🇦🇹 🇧🇬 🇭🇷 🇨🇾 🇨🇿 🇩🇰 🇪🇪 🇫🇮 🇩🇪 🇬🇷 🇭🇺 🇱🇻 🇱🇹 🇱🇺 🇲🇹 🇳🇴 🇵🇱 🇷🇴 🇸🇰 🇸🇮 🇸🇪

“Aamir has taken excellent care of our iOS payments SDK. He played a central role in integrating ProcessOut, helped us pass the PCI compliance check, and drove technical discussions through several RFCs.”

Emil Dodevski, Engineering Manager

Payments Platform, DoorDash / Wolt

About

Product engineer.
Systems thinker.

I’m a Senior Software Engineer at Wolt | DoorDash, based in Berlin. My work spans iOS interfaces, payment architecture, and the systems that connect them.

My studies at TU Berlin shaped how I think about distributed systems. A decade of building software has taught me to care just as much about the details people see and feel.

10+Years in software engineering

11iOS apps contributed to

TU BerlinSoftware engineering & distributed systems

Experience

Where I’ve shipped.

A decade in software engineering, across FinTech, health, e-commerce, and enterprise.

Currently

Senior Software Engineer

Wolt | DoorDash

Jan 2023 to Present

Berlin, Germany

Payments and FinTech. I own the iOS payments surface, the layer between a customer tapping “Pay” and money actually moving. More than 30 payment methods and 22 payment service providers, unified behind one cross-brand SDK.

The full payment lifecycle. Integrating provider-managed card tokenization, authorization, 3DS/SCA authentication, and third-party redirects. I handle the return path and reconciliation so customers receive a clear, reliable payment result.
One SDK, many providers. Every PSP models the same concepts differently. Some want a nonce, some a session, and some a web-based flow. I designed the abstraction that normalizes them behind a single protocol-driven interface, so adding a provider is a conformance, not a rewrite of checkout.
Providers and regional rails. Integrated Adyen, Finaro, Stripe, Braintree, Spreedly, ProcessOut, Worldpay, Juspay, and market-specific benefit schemes including SZÉP cards.
Wallets, redirects, and meal benefits. Apple Pay and device-attested wallets, bank-redirect methods across European markets, BNPL, gift cards and stored balance, tipping, and employee benefit schemes across products with their own regulatory shape, currency rules, and market availability.
Beyond card checkout. Built gift cards, balance top-ups, account credits, and corporate invoicing flows. Each has distinct funding, eligibility, and reconciliation rules.
Server-driven checkout UI. Built the payment sheet as a slot-based rendering engine fed by the backend, so a new method can launch in a market without shipping an app release. Cuts the feature-to-customer latency from an App Store cycle to a config change.
Cross-brand by design. One codebase serving three consumer apps with different brands, markets, and native payment stacks. That means the boundaries have to be real. Protocol seams and dependency injection over shared mutable state.
Correctness you can prove. Payments is the worst place to find out you were wrong in production. I built the E2E automation pipeline for payment flows in CI, drove characterization tests ahead of refactors, and treated testability as a product requirement rather than a nice-to-have.
Modernizing while shipping. Migrated payment modules to Swift 6 strict concurrency, decomposed monolithic view controllers into a presenter/slot architecture across a sequenced series of small reviewable changes, with no big-bang rewrite or feature freeze.
Regulated, audited, gated. Work under PCI constraints, age and jurisdiction restrictions, and market-specific compliance rules. Behavior changes roll out behind feature flags and experiments to make releases controlled and measurable.
Cross-functional delivery. Aligned iOS with Android and backend across three consumer brands, so every platform agrees on what a payment is and how it should behave.

Swift UIKit Adyen Spreedly Stripe Braintree ProcessOut Worldpay Credorax/Finaro Juspay SZÉP Mosaic Bazel SPM Maestro OpenTelemetry swift-dependencies Fastlane Bitrise

Lead Software Engineer, iOS

Astrivis

Oct to Dec 2022

Zurich, Switzerland

Led iOS engineering at a Zurich-based startup that transforms smartphones into professional 3D scanners used in orthotics, prosthetics, custom footwear, and eyewear. Laid the technical foundation for Astriscan.

Built the iOS 3D scanning experience with real-time live feedback and quality assessment during capture
Implemented on-device 3D model generation, giving users an instant preview in under 30 seconds without cloud dependency
Integrated RGBD camera APIs for body-part scanning with mm-level accuracy
Defined architecture, technical direction, and development workflow for the mobile product

Swift ARKit 3D Scanning Computer Vision On-Device ML Technical Leadership

Technical Lead, Senior Software Engineer

kfzteile24 GmbH

Oct 2020 to Sep 2022

Berlin, Germany

Led the iOS team at Germany's leading online auto parts retailer. Drove architecture decisions, mentored engineers, and shipped a high-performance e-commerce app.

Led iOS architecture migration and established clean modular patterns
Managed code review processes and mentored junior & mid-level engineers
Shipped e-commerce features: product search, checkout, order tracking

Swift UIKit E-Commerce Team Lead

iOS Engineer

AMBOSS

Jul 2019 to Sep 2020

Berlin, Germany

Ground-up rewrite of the world's leading medical education platform, used by doctors and students in 180+ countries. Rebuilt it on a scalable architecture with carefully crafted motion and a genuinely considered reading experience across both the knowledge library and the Q-Bank exam prep app.

Swift UIKit Medical Education Offline-First