Full CV
The CV covers the roles since 2001, including the earlier projects not listed here. Both language versions contain the same information.
Projects
Projects and results
Selected projects from Daniel Hartmann’s twenty-five years as a developer and architect. They include work for clients and employers, as well as our own product, Reynt.
Each entry identifies Daniel’s role and whether he worked as an employee or through his own company. For work done in employment, we name the employer. Clients of those employers remain unnamed. The descriptions cover his contribution without disclosing confidential project details.
MUSES — school IT platform for school authorities
School IT staff in three federal states use one interface for five vendor systems. Ticket requests are stored until the ticketing system can receive them.
MUSES gives school authorities and IT staff in Baden-Württemberg, North Rhine-Westphalia and Saxony a shared interface for Wi-Fi access, support tickets, devices and content filtering. Its .NET 9 backend uses Clean Architecture, minimal APIs and MediatR/CQRS to integrate five external SaaS services behind one REST API. Vendor-specific models stay outside the domain logic. The React 19 frontend uses OIDC authentication and role-based access, with an accessible React Aria component library published on npm and documented in Storybook. A Rust service stores ticket requests and retries failed submissions with backoff. The system runs on Kubernetes at a German hosting provider, using Terraform, FluxCD, Helm and SOPS-encrypted secrets.
- C#
- .NET 9
- Clean Architecture
- MediatR (CQRS)
- React 19
- Next.js
- React Aria
- Storybook
- Rust
- OIDC
- Kubernetes
- FluxCD
- Terraform
- SOPS
- Azure Pipelines
Reynt — multi-tenant rental & booking platform
Stripe Connect and PayPal were removed without changing the settlement logic. The four APIs were migrated from Elysia to Hono in one week, with no changes to the domain packages.
Reynt is a multi-tenant booking SaaS developed and hosted in the EU. It reached production after eleven months of development alongside a day job. Thirteen packages contain four Hono APIs, three Nuxt 4 frontends, an Astro marketing and documentation site, and a headless SDK. Integration tests run against PostgreSQL in CI. Row-level security enforces tenant isolation; personal data is encrypted per tenant, searchable through blind indexes and erasable through key destruction. The platform covers bookings, multi-option offers, an append-only payment ledger, invoicing, settlements, pricing and availability. It also provides a CMS storefront builder, multilingual SEO and support for local tax and registration requirements. AI features include an agent whose proposals require operator approval, an MCP server and in-app help backed by retrieval-augmented generation.
- TypeScript
- Bun
- Hono
- Nuxt 4
- Astro
- PostgreSQL (RLS)
- Drizzle ORM
- Mollie
- Kubernetes
- MCP
Smartflow AI — workflow automation platform
Architecture and development of the backend for an AI-powered workflow automation platform.
- Kotlin
- KTOR
- TypeScript
- Python
- TensorFlow
- RabbitMQ
- PostgreSQL
Lottery platform for charitable associations
Every draw is verifiable after the fact: the seed is generated cryptographically and stored alongside the result, so an association can show a supervising authority how its winners were determined.
The platform supports charitable associations through the process of running small lotteries, from filing with the responsible authority to ticket sales, the draw and settlement. A rule set records the applicable steps, deadlines and authorities by federal state and district. Official administrative boundaries are stored in PostGIS to support region and radius searches within permitted sales areas. The .NET 8 backend uses Clean Architecture, minimal APIs and MediatR/CQRS, with a SvelteKit frontend. The platform supports SEPA direct debit, identity verification through an external provider and PDF generation for the required documents.
- C# / .NET 8
- Clean Architecture
- MediatR (CQRS)
- PostgreSQL / PostGIS
- SvelteKit
- OIDC
- Kubernetes
Web3 NFT store & trading platform
Architecture and development of an NFT trading platform, including its frontend, backend and Polygon smart contracts.
- Solidity
- Polygon
- Kotlin
- KTOR
- TypeScript
- React
- MongoDB
Allsky — drone detection over critical infrastructure
Fixed all-sky cameras monitor the airspace above critical infrastructure. Machine-learning models analyse the images to detect and classify flying objects, particularly drones. The platform tracks their trajectories and reports suspicious approaches.
- TypeScript
- Vue.js
- Kotlin
- Python
- TensorFlow
- OpenCV
- MQTT
- Flutter
Education management system for the public sector
The team received a written assessment of the code and architecture, with recommendations for further development.
Code and architecture reviews, recommendations and developer support.
- TypeScript
- Node.js
- Vue.js
- GraphQL
- Elasticsearch
- PostgreSQL
Monitoring web application for 3D printers
Architecture and development of frontend and backend, plus the shared libraries and tool stack behind them.
- TypeScript
- Angular
- ngrx
- GraphQL
- Node.js
- Elasticsearch
- PostgreSQL
Frontend tool stack & component library
The company’s client projects used a shared technology stack and component library.
Frontend architecture, interface definitions, shared libraries and build tools for client projects, with support for the developers using them.
- TypeScript
- Angular
- VCL / ng-vcl
- rxjs / ngrx
- webpack
- GraphQL
Client references
When we discuss a potential engagement, we can put you in touch with former clients who can describe their experience of working with Daniel.
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