Full-stack product engineering for teams building complex, dependable software.

AA Digital Services is an independent engineering consultancy led by Aris Apostolakis. We design and deliver web, mobile, backend and cloud systems — with particular experience in payments, regulated data, and products where correctness matters.

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What we do

We are a strong fit for teams building software that has to be right: a product moving money, holding personal data, or working in a domain where a subtle error is expensive to find late. That might be a founding team shipping a first version, or an established product team carrying a system that has outgrown the way it was built.

Taking on the whole stack rather than one layer of it means the seams between them get designed rather than negotiated — which is where most of the cost lands in a small team. Much of the experience behind that comes from financial services: cross-border payments, transaction processing, and the operational discipline those systems demand.

Frontend engineering

React on the web and React Native on iOS and Android, sharing code where it pays to — interface, state, offline behaviour, and the accessibility and performance work that decides whether people keep using it.

Backend engineering

Java and Spring Boot services, REST APIs, relational data modelling on PostgreSQL, and the distributed-systems work that holds them together.

Cloud architecture

AWS microservices and serverless infrastructure defined as code — along with the gateways, queues and storage those systems depend on.

Fintech and payments

Digital wallets, payments, FX, ledgers and settlements — with the reconciliation, auditability and AML and sanctions-screening obligations that come with moving regulated money.

Selected work

Hubpay

Selected engagement

Cross-border payments platform, UAE — engaged through AA Digital Services OÜ.

Hubpay runs a financial platform for consumers and businesses in the UAE — digital wallets, payments, FX, settlements and the accounting underneath them. The hard part is not throughput but correctness: every movement of value has to be traceable, reconcilable and defensible to a regulator.

Role: full-stack across the platform — backend services, the customer-facing web and mobile applications, and the internal operations tooling.

Delivered

Java and Spring Boot services on PostgreSQL, event-driven — wallets, payments, FX, ledger management, receivables and settlements.
Integrations with banks, payment partners, and AML and sanctions-screening providers, behind secure REST APIs.
React and React Native customer experiences, plus the operations dashboards used to investigate financial workflows.

Result: automated reconciliation and transaction-matching that cut manual intervention and strengthened financial controls.

Full history on LinkedIn.

How we work

You work with the engineer

Engagements are led and delivered by Aris. For work that needs more hands than one pair, we bring in trusted collaborators we have worked with before — but there is never an account layer between the brief and the build.

Built to be handed over

Code, infrastructure and documentation are written on the assumption that someone else will maintain them. Nothing is left resting on one person's memory.

Honest scoping

Better to say a piece of work is not worth doing than to bill for it. Estimates come with the assumptions behind them stated plainly.

Remote, across Europe

Registered in Estonia, working remotely from Crete, with clients across the EU and beyond. English and Greek.

Working together

If you have a project in mind, the fastest way to start is a short conversation about what you are trying to build and why. We will tell you honestly whether it is something we are the right fit for.

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