Curriculum Vitae
Tomáš Štěstí
Senior Software Developer / Java · Kotlin · TypeScript · Cloud
A senior developer who has been building software since 2015 — starting as a verification engineer in telecom, writing his first professional Java in Unicorn's Java Hatchery trainee program. Since then he has shipped production software across industries: a crypto exchange and the CZKC Czech stablecoin, global logistics at DHL, scanless retail in Germany, RCS messaging for Vodafone UK, and a booking platform for Der Touristik. He is usually the one handed the integration nobody wants — blockchain, payment rails, real-time tracking.
Along the way he has worn several other hats — besides back-end development he has worked as a DevOps Engineer, Scrum Master, Java competence lead, and PO / PM on projects built on the Tabidoo low-code / no-code platform.
Today he works as a full-stack developer with an architect's reach. He develops and modernizes a fintech / crypto platform — moving a long-running core into current technology piece by piece, without stopping production. Alongside that he builds and runs his own SaaS product end to end, from architecture to production, including infrastructure as code on AWS and an LLM-backed AI service.
At a glance
Skills
Languages & platforms
Backend
Cryptography & security
Frontend
Mobile
Cloud
DevOps / IaC
Data
AI / LLM
Observability & quality
Legacy-system modernization
Working with production systems built on versions that are no longer supported. The job is not to extend those technologies, but to keep the system running while moving it into the current stack piece by piece: carving functionality out into new services, running the old and new interfaces side by side, migrating live with no downtime.
In other words: gradual replacement, not a big-bang rewrite.
Domains & practices
Languages
Experience
— nowPrague / hybrid
- Development and gradual modernization of a multi-module banking platform (Java / Kotlin) and its React front end — from the ledger core to the admin console. The work is keeping production running while carving functionality out into newly written services.
- A new admin application built on Spring Boot 3 + Kotlin 2.0 + Java 17 and React 18 / Vite: migrating functionality off the older console step by step. Designed and implemented the whole stack, including the backend API contract.
- Regulatory work: AML / KYT, Travel Rule (VASP↔VASP) and KYC — from design to production, including audit traceability and reporting for the Czech National Bank.
- Treasury and exchange operations: tooling for balance management, account statements, and internal book entries.
- Data protection: encrypting personal data with OpenPGP (BouncyCastle / PGPainless) — an app-side implementation that allows migrating from database-level encryption into the application layer.
- Third-party API integrations: Tatum (detecting Ethereum transactions on chain), Alchemy (validating them), ThePay and ComGate (CZK / EUR gateways), CitFin and FIO (bank statement ingestion in ISO 20022), BankID, Bitcoin Core RPC.
- CZKC (Czech stablecoin): services around buying and selling the ERC-20 token (Spring Boot, OAuth2 resource server).
- Prototypes and internal tooling: a mobile client in Compose Multiplatform (Android / iOS / Wasm from one codebase), and a local OCR / MRZ service for reading ID documents with an auto-accept / manual-review gate (Python, Docker, local vision model — no cloud calls).
- Real-time production incident response and hot-fix deployment; coordinating versioning and DEV / TEST / PROD releases with the front-end team.
- Front-end and back-end development on the booking platform used by travel agencies.
— 2023Germany
- Designed and built microservices for the cloud backend that processes the customer journey end to end — from shop check-in through to checkout and payment.
— 02/2023In parallel with the DHL Global Forwarding engagement.
- Led the Java competence and ran hiring interviews.
- Trained and onboarded junior developers, prepared them for projects, and supported internal knowledge sharing and talks.
- Tabidoo low-code / no-code platform — internal development: analysed internal processes and data flows; designed solutions, prioritized the backlog and ran delivery of individual modules and their integrations (HR, inventory, tasks, finance). TLDR: from filing cabinets to monitors…
- Tabidoo low-code / no-code platform — client work: digitized company processes and data; gathered requirements from customers and formalized them into a backlog; prioritized tasks, allocated developer time and verified the output; presented solutions to stakeholders and collected feedback.
— 12/2021In parallel with Neon IT s.r.o.
- Designed, built, deployed and ran reactive microservices running in the cloud.
- Processed and served real-time package-tracking data aggregated from many DHL backend systems under one unified API.
— 12/2019Madrid, Spain
- Designed, built, tested, deployed and supported new microservices for an asynchronous multimedia-messaging platform.
- Supported the RCS standard implementation in Message+.
— 2017Brno
- Where it started: software verification engineering at Mavenir (formerly Comverse / Xura) and telecom internships in Brno.
- Wrote his first professional Java in Unicorn's Java Hatchery trainee program.
Own products & projects
Alongside client work he builds and runs his own products, in a role that amounts to CTO of a small product team — architecture, implementation, infrastructure, security and operations in one person. Product names are deliberately omitted; what matters is the domain and the technical solution.
SaaS platform for facility management and cleaning services
- Domain: planning and supervising cleaning work — an admin SPA for the FM company, a QR flow for staff on site, a separate portal for the end client, real-time monitoring, alerting, shift management and workforce management.
- Multi-tenancy and security: ownership of the database schema, RLS policies, separate least-privilege DB roles, tenant ID always taken from the verified JWT (never from LLM output).
- AI backend for natural-language analytics: FastAPI + WebSocket, provider-agnostic LLM via LangChain, rate limiting on an append-only usage ledger, read-only DB role with RLS enforced.
- Infrastructure as code: Terraform and Ansible, CI/CD via GitHub Actions, monitoring run from a different AWS region than the services it watches.
- Localization into 4–6 languages, plus integration of an external attendance API as a standalone microservice.
Search across Czech legislation and court decisions
- Domain: legal search for non-lawyers — the user describes their case in plain language and gets back the relevant in-force laws and the rulings that touched them.
- Solution: ingest of legislation and decisions from public sources with a change-capture manifest, linked by citation, retrieval over full-text search with a layer ready for semantic embeddings, and LLM synthesis of the answer.
Serverless web platform and micro-apps
- Domain: a set of independently deployed micro-apps (quizzes, games, tools) sharing one domain.
- Solution: the domain is split between a Pages project and several Workers owning their own routes — each app is developed and deployed in isolation. Terraform provisions the infrastructure; CI ships content and idempotent D1 migrations.
E-commerce for a digital product
- Domain: selling a digital product to end customers — sales page, qualifying quiz, and a lead magnet in exchange for an email address.
- Solution: a serverless backend on D1 acting as a small in-house CRM (contacts, quiz results, feedback, events), product typesetting to PDF from Markdown sources, and a custom design system.
Education & courses
Brno University of Technology (VUT)
Robot Dreams — Cloud Application & Data Architecture
A cloud-architect course on designing complex cloud solutions. Topics covered: VM to serverless, container orchestration (Kubernetes, Helm, Kustomize), blue-green and canary deployment, API gateways, hub-and-spoke enterprise networking, design patterns (orchestration vs. choreography), observability, storage types and performance trade-offs, redundancy and consistency (Cassandra), distributed data processing and lakehouse (Databricks), machine learning, Infrastructure as Code and SRE, chaos engineering and SLOs, CI/CD and DevSecOps with GitOps (ArgoCD).
Final thesis: the architecture of a cloud-native transaction system.