Software & AI studio · Tallinn
Software that ships — and AI that delivers.
Devaster is a Tallinn-based software studio. We design and build custom web apps, SaaS and AI integrations for small and growing businesses — end-to-end, senior-led, and built to last.
Services
What we do for your business
Four ways Devaster helps small and growing companies build, ship and get more out of software — each backed by products we've shipped and systems we've run.
AI integration & automation
Put AI to work where it actually helps — assistants and chat over your own data, document and content processing, and automation that removes repetitive manual work. Wired into your existing systems, not bolted on the side.
- LLM assistants & chat
- RAG over your own data
- Workflow automation
- MCP & API integrations
Custom web apps & SaaS
Bespoke web applications and SaaS products, designed and built end-to-end — from idea and data model to a fast, secure product your customers actually enjoy using.
- Full product builds
- Customer portals & dashboards
- Secure auth & payments
- Built to scale
Architecture & fractional CTO
Senior technical leadership without a full-time hire — system architecture, security and code reviews, cloud and CI/CD, and a steady hand to guide your team and roadmap.
- System architecture
- Security & code review
- Cloud, CI/CD & DevOps
- Team mentoring
Data apps & dashboards
Turn data into decisions — pipelines that collect and clean it, plus dashboards, maps and reports that make it usable. Your data, open data, or both.
- ETL & data pipelines
- Dashboards & maps
- Open-data integration
- Analytics & reporting
Selected work
Products we've built and shipped
We don't just advise — we ship. These are independent products Devaster designed, built and runs end-to-end, each live and in public use: from data pipeline and modelling to design and deploy.
How we work
Senior hands, start to finish
A simple, honest way of working — the person who scopes your project is the one who builds and ships it.
- 01
Discovery & scope
We map the problem, your data and your goals, then agree on a clear scope and approach — no surprises.
- 02
Architecture & build
We design the architecture and build it end-to-end, shipping in small, working increments you can see.
- 03
Ship & support
We launch, hand over cleanly with documentation, and stay available for support and the next iteration.
Team
The senior engineer behind Devaster
Devaster is a one-person studio — led by Jürgen Hannus, a software architect, senior full‑stack developer and AI specialist based in Tallinn, Estonia. When you work with Devaster, you work with him directly.
Over 15+ years he has designed and built Java and Spring enterprise systems for national e‑government (on X‑Road), banks and international SaaS companies — shaping architecture and CI/CD, leading and mentoring teams, hardening security (OWASP, SAST), and taking AI from prototype into production.
It means no handoffs and no juniors learning on your budget: the person who scopes your project is the one who architects, builds and ships it.
In brief
- Based in
- Tallinn, Estonia
- Founder
- Jürgen Hannus
- Education
- TTÜ IT College — IT Systems Development
- Languages
- Estonian (native) · English (professional) · German (working)
Capabilities
The toolkit behind the work
A pragmatic, full-stack toolkit — deep on the JVM and cloud, and increasingly centred on getting AI into production.
AI / Machine learning
Languages
Backend
Cloud & infrastructure
Frontend
Data & messaging
CI / CD
Testing
Observability
Integration
Track record
15+ years across e‑gov, fintech and SaaS
The experience behind Devaster — from national e‑government platforms on X‑Road to international AI SaaS, as developer, lead and architect.
Trinidad Wiseman
2025 — presentArchitect / Lead Software Developer
Technical architect and lead full-stack developer on the modernized Estonian national export portal (EXPO) — unified digital services, export guidance and AI-powered translation of user-generated content. Improving CI/CD and internal tooling, mentoring backend developers, enforcing standards.
Java 25Spring Boot 4Angular 20Microservices / MFEX-RoadKubernetesRabbitMQOpenAILead Software Architect
Led architecture of an AI-powered legal practice-management SaaS with built-in CRM for law firms worldwide — security (OWASP remediation, SAST), AWS infrastructure and observability, AI-driven features, PostgreSQL performance, release management and team hiring & mentoring.
Java 21Spring Boot 3ReactTypeScriptAWS (ECS, RDS, S3)PostgreSQL RLSDatadogOpenAIFinestmedia
2023 — 2024Architect / Lead Software Developer
Architected Estonian state information-system services — the RIHA global management system, the consent service and a personal-data tracker — on X-Road. Led developers, drove code quality and clean-code practices, and presented on AI across the company.
Spring Boot 3Java 17Angular 15PostgreSQLX-RoadSOAPDockerCamelot Technologies
2022 — 2023Architect / Developer
Designed and delivered a Spring backend gateway between a Vue.js frontend and Java services, with user registration, authentication and authorization (JWT + 2FA).
Spring Boot 3Java 17PostgreSQLWebSocketPrometheusGrafanaLead Software Developer
Architected Futugrid — a fully automated real-time system managing household plug-in devices to improve grid efficiency and savings — and led the Health & Well-being information system (TeIS) for work-safety management.
Java 17Spring Boot 3KafkaAWS IoTKubernetesVue.jsCamundaGrafanaIcefire
2013 — 2019Software Developer
Built tax, customs and compliance systems for the Estonian Tax and Customs Board, PlanetID mobile authentication, and self-service applications for Elisa and Luminor Bank.
JavaSpring MVC / BootOraclePostgreSQLCamunda BPMNSOAP / RESTKnowit (flowit)
2011 — 2012Software Developer
CRM development for Tre (Sweden) and automated-testing tooling for SK ID Solutions (TempelPlus).
JavaPL/SQLSOAPTibcoSEB Bank
2010 — 2011Software Developer
Cost-budgeting and monitoring web application (EIS).
PL/SQLOracle APEXJavaScript
FAQ
Frequently asked questions
Quick answers about what Devaster does, how we work, and who does the work.
What does Devaster do?
Devaster is a Tallinn-based software studio. We build custom web apps and SaaS, integrate AI (LLMs, RAG, MCP) into businesses, and provide software architecture and fractional-CTO support — for Estonian and international clients.
Do you work with small businesses?
Yes — small and growing companies are exactly our focus. You get a senior engineer who scopes, builds and ships your project directly, without layers or juniors learning on your budget.
How do you engage and charge?
Either fixed-scope projects or an ongoing retainer / fractional-CTO arrangement. We agree the scope and approach up front, so there are no surprises. Email info@devaster.ee to talk through what you need.
Can you add AI to our product?
Yes. Taking AI into production is our specialty — assistants, RAG over your own data, automation and MCP integrations — wired into your existing systems rather than bolted on.
Who is behind Devaster?
Devaster is a one-person studio led by Jürgen Hannus, a software architect with 15+ years across Estonian e‑government, banking and international SaaS. You work with him directly. (Devaster is the trading name of Devaster OÜ.)
Let's build something for your business.
Tell us about your project — a new product, an AI feature, or a system that needs a senior hand. The fastest way to reach us is email.
info@devaster.ee