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An app your customers keep, on every phone they own.Mobile App Engineering

Crafting reliable, consumer-grade mobile apps across iOS and Android from a single, efficient codebase.

Understanding the discipline

What mobile app engineering means for modern business.

A mobile app is a channel a business owns outright. It sits on a device people carry everywhere, it works whether or not they think to visit a website, and it is the only place a company can reach a customer or a colleague directly, with permission, in the moment that matters.

For most organisations it stops being a product and becomes infrastructure — the way orders are placed, the way work is dispatched, the way a service is actually delivered. Which is why the decision is rarely about an app at all. It is about which part of the business is moving onto the device.

  • Apps stopped being products and became operating channels.

  • Customers moved from calling to serving themselves.

  • Field and frontline work moved off paper and onto devices.

  • The phone became a revenue line, not a marketing cost.

Customer applications

The apps your market uses — ordering, booking, banking, tracking, support. They deepen a relationship you already have, through a channel no platform sits in the middle of.

Business applications

The apps your operation runs on — dispatch, inspection, approvals, stock. They replace paper and phone calls with a process that records itself as it happens.

Enterprise mobility

The apps your workforce carries — secure access to systems, data and approvals from wherever the work is, under the same controls IT applies to everything else.

The business case

Why businesses invest in mobile app engineering.

Returns that show up on the business, not on the engineering backlog.

  • 01

    Customer engagement

    A direct, permissioned channel to the people who buy from you — one that reaches them in the moment rather than waiting for them to remember your website exists.

  • 02

    Operational efficiency

    Work that travelled by phone call, paper form and re-keying becomes a single flow that records itself, so the cost of every transaction falls rather than the headcount rising.

  • 03

    Employee productivity

    Frontline and field teams get what they need where the work happens, instead of returning to a desk to type up what they already did once.

  • 04

    Business growth

    New services, new territories and new revenue models become possible once distribution stops depending on physical presence or a browser session.

  • 05

    Digital transformation

    Mobile is usually where transformation becomes visible — the first place a legacy process gets re-designed rather than digitised exactly as it was.

What we build & capabilities

The things you can commission — and what each one ships with.

Defined engagements, one at a time: the thing itself on screen, and the capabilities that come with it.

01 / 09

Customer apps

The app your market lives in to buy, book, track and get help — a channel you own outright, reaching people on the device they never put down instead of waiting for them to remember your website.

Capabilities

  • Accounts and profiles
  • Ordering and booking
  • Order tracking
  • In-app support
  • Ratings and reviews
  • Loyalty and rewards

Business outcomes

Where the business is today, and what changes.

The operational difference, in the terms the business already measures itself in.

A process that runs on paper forms and phone calls.
A digital workflow that records itself as the work happens.
Customers calling to ask where their order is.
Self-service in the app, and a support line that only handles exceptions.
Forms filled on site and re-keyed at a desk hours later.
Captured once at the point of work, even with no signal.
Updates that reach the business a day late, by email.
Real-time visibility for everyone who needs it.
Two platform teams, two backlogs, two release cycles.
One codebase reaching both app stores in the same release.

Cross-platform reach

Higher engagement & retention

Faster time-to-market

Industries we serve

The same discipline, shaped to your sector.

Regulation, procurement and legacy estate differ by industry — and the engagement is shaped around them, not in spite of them.

Our engineering process

How the engagement actually runs.

Every stage has an owner, an output, and a point where you can change direction.

  1. 01

    Business discovery

    Understanding what the app has to change commercially, before anyone discusses features.

  2. 02

    Product strategy

    Scope, sequence and success measures agreed — including what deliberately is not in version one.

  3. 03

    UX research

    The journeys people actually need to complete, mapped with the people who will use them.

  4. 04

    UI design

    Interfaces designed as a reusable system and reviewed on real devices, not in a slide.

  5. 05

    Development

    Built in short, reviewable increments, so progress is something you can hold rather than read about.

  6. 06

    Quality engineering

    Automated and on-device testing through delivery, across the handsets your users actually own.

  7. 07

    Deployment

    Store submission, phased rollout and monitoring, with a rollback path that has been rehearsed.

  8. 08

    Continuous improvement

    Release health, retention and feedback feeding the next iteration, by a team that already knows the code.

Why Sumago

Why teams choose Sumago.

The technology partner serious businesses build with — and stay with.

Future-readyProven at scaleCertified qualityBuilt to lastTrusted partner

Business-first thinking

Every engagement starts from the commercial outcome, not the feature list. If an app is not the right answer, that gets said early.

Enterprise-grade engineering

Typed, tested and documented delivery under independently certified process — ISO 9001:2015 and CMMI Level 5.

Scalable architecture

Built for the load expected in year three, not only the load present at launch.

Human-centred design

Research before screens, and interfaces designed for the conditions people genuinely use them in.

Security by design

Authentication, storage and data handling treated as part of the build rather than a review before launch.

Agile delivery

Short increments, visible progress, and a point in every cycle where direction can change without penalty.

Cross-industry experience

Thirteen years across logistics, manufacturing, healthcare, public sector and financial services.

Long-term partnership

Support and improvement long after delivery, from the team that built it.

Technology ecosystem

Mainstream technology, chosen so you can hire for it later.

The stack is a means, not a position. It gets chosen against your constraints — and it stays maintainable by people who aren't us.

Cross-platformNative iOSNative AndroidBackend & APIsCloud & hostingApp analytics
  • Slack

Proof of work

Work that has already shipped.

Real engagements, named clients, and what changed for the business behind them.

An Aggregator Platform for a Fragmented, High-Value Market
Retail & E-commerce

An Aggregator Platform for a Fragmented, High-Value Market

Client challenge
A vast, high-value trade was running without a home. Buyers had no reliable way to discover genuine inventory or compare it with confidence; sellers had no efficient way to reach a wider audience; and with no trusted intermediary in the middle, every transaction carried friction and risk. The value was undeniable — but it was scattered across countless disconnected sellers, invisible to the buyers who wanted it. The opportunity was not a better listing site; it was to organize an entire market.
Our solution
A B2B2C aggregator platform that brings both sides of the trade onto one trusted marketplace. Sellers gain reach and a professional storefront through a subscription that scales with their ambition; buyers gain effortless discovery, confident comparison, and a direct line to verified sellers; and the platform operator governs quality and trust across the whole ecosystem — verifying participants, curating what appears, and keeping the marketplace credible as it grows. Two purpose-built experiences, one connected network. ### The platform A three-part ecosystem on one shared backend, each surface built for a different user: - **Buyer App (Android & iOS)** — *for the consumer.* A simple, mobile-first way to discover inventory, compare with confidence, and connect directly with verified sellers. *How it helped:* removed the friction and doubt that kept buyers away, drawing demand onto the platform and giving the marketplace its pull. - **Seller App (Android & iOS)** — *for the dealer.* A self-serve storefront to list inventory, manage listings, respond to interest, and track demand — all from a phone. *How it helped:* gave sellers real reach and control, attracting the supply that makes the marketplace worth visiting and driving the recurring subscription revenue. - **Web Operations Platform** — *for the operator.* The command layer to verify participants, curate listings, run the subscription model, and govern trust across the whole market. *How it helped:* kept the marketplace credible and commercially healthy as it scaled — the trust engine that lets both sides transact safely. ### Architecture highlights - **API-first, shared-backend architecture** — two mobile apps and the operator platform are served by one consistent API, so every surface stays in sync. - **Discovery-optimized data layer** — catalog modeling and indexing tuned to keep search and comparison fast as listings scale into the thousands. - **Horizontally scalable and cache-backed** — stateless services plus caching and a CDN for media keep the experience fast under load. - **Decoupled monetization layer** — subscription and payment logic is isolated from the marketplace core, so commercial rules can evolve without risk. - **Secure, token-based auth** — frictionless OTP onboarding with JWT-secured sessions across every app. ### Technology stack The buyer and seller apps are built as **cross-platform React Native** mobile applications — one build that runs natively on **both Android and iOS** — while the operator platform and backend run on the **MERN stack** (MongoDB · Express.js · React · Node.js).
Business impact
The platform converts a fragmented, informal trade into an organized, trust-driven market with its own gravity: the more sellers list, the more buyers browse, and the more each side has a reason to stay. Monetization comes not from one-off fees but from a **recurring-revenue subscription model** that grows with seller success — a business that compounds as the network expands. For the operator, it turns market chaos into a defensible, scalable, and self-reinforcing asset.

Marketplace Architecture · Trust & Verification · Discovery & Search · Subscription Monetization · Operator Governance