Passion, not just work
Software development has never been a 9-to-5 job for us. We dig deep into problems, prototype relentlessly, and care about every detail — from API design to deployment.
Mindoo GmbH · Karlsruhe, Germany
We love what we do.
We think outside the box.
We explore the limits of technology.
Mindoo is a software engineering company founded in 2008 by Karsten Lehmann and Tammo Riedinger. Both founders have been professional software engineers since 2000, building graphical desktop applications, web platforms, collaborative tools, and data-intensive business systems.
Over the years our technology stack has evolved continuously — from Java Swing and HCL Notes/Domino through Spring Boot, React, Vue.js, and MongoDB to Kotlin, end-to-end encryption, and LLM-powered development tooling. What has stayed the same: a passion for pushing technology forward and delivering software that actually works.
What drives us
Privacy & data ownership
We believe users should control their own data. That conviction shaped our newest product MindooDB — an end-to-end encrypted, local-first sync database where neither the server nor the operator can access the content.
Rapid technology adoption
We embrace new platforms early. From being an IBM Design Partner testing pre-beta Notes/Domino releases to adopting LLMs for code generation, RAG pipelines, and AI-assisted architecture work — we stay at the frontier.
What we do
Architecture & engineering
We design and implement modern web and backend systems. Our current stack includes Spring Boot, React, Vue.js, Node.js with TypeScript, Kotlin, MongoDB, and PostgreSQL. We act as hands-on architects who write production code, not just diagrams.
Migration & modernization
We help organizations migrate from legacy application stacks to maintainable, modern systems. We have deep experience transforming monolithic applications into service-oriented architectures while preserving business logic and data integrity.
Product development
We build products from concept to production. Our latest is MindooDB, an open-source end-to-end encrypted sync database (Apache 2.0). Previous products include MindPlan (collaborative mind mapping & project management) and Mindoo CMS.
AI & LLM integration
We integrate large language models into development workflows and enterprise applications. From RAG pipelines that augment LLM prompts with structured business data to AI-assisted code generation tooling — we bring practical AI into real projects.
Selected project history
Over nearly two decades we have delivered solutions across a wide range of industries and technology stacks. Here are some highlights.
Haven
Haven is a calm, collaborative workspace where your team works with notes, files, apps, and data - encrypted by default and installable on any device. It runs on MindooDB, an open-source, local-first sync database you can run on your own servers, in your own jurisdiction; the server only ever sees ciphertext. Real data sovereignty, without giving up real-time collaboration. mindoodb.com
MindooDB
An end-to-end encrypted local-first sync database for desktop and mobile devices. All data stays on the user's devices and is synchronized via server or peer-to-peer. Every change is digitally signed. Available under the Apache 2.0 license. mindoodb.com/mindoodb
E-commerce & consumer goods platform
Architecture and ongoing development for a large consumer goods company's online shop, event booking / product tasting applications and other internal enterprise applications. Technologies: Spring Boot, Vue.js, React, MongoDB, PostgreSQL, Google Datastore, HCL Notes/Domino.
Domino JNA & Domino JNX
Domino JNA is our open-source Java library providing cross-platform access to the HCL Domino C API via JNA — exposing functionality far beyond the standard Java API. Together with HCL's Innovation Labs and Jesse Gallagher, we then built Domino JNX, the modern Java API that powers the HCL Domino REST API.
Mindoo CMS
A Domino-powered web content management system with live editing, responsive templating, full history, and approval workflows. Used by municipal websites and a regional print shop's collaborative article authoring platform serving 3,000+ users.
Local-first mobile document client
An local-first mobile document client framework with a configurable web UI, diff-based synchronization, and automatic database migrations for iOS and Android.
Weilgut eOffice
Architecture and development of eOffice, an OSGi-based CRM system for the HCL Notes/Domino platform. Built with Java on the backend and Sencha ExtJS on the frontend, eOffice provides contact management, activity tracking, sales pipeline, and document workflows for professional services firms — tightly integrated into the Domino collaboration environment.
KPI dashboard for global car manufacturer
A responsive web-based management dashboard that transforms high-volume operational data into configurable KPI views and rich visualizations, designed as a clean, executive-ready interface for fast weekly decision-making.
Field research platform for global energy-drink brand
A mobile-ready web application for capturing on-the-go market-research data, feeding a searchable, multi-country database of competitor products and variants for fast field-level insight.
Succession planning for automotive management
Project support and quality assurance for the rollout of a succession planning system targeting management positions at a major automotive group.
Intranet CMS for automotive group
Design and implementation of an HCL Notes/Domino-based web content management system powering the corporate intranet of a major automotive group.
MindPlan
A collaborative mind mapping and project management desktop application (Java / Swing), developed in partnership with Haus Weilgut GmbH. Awarded the IBM Lotus Award TCO (2008) and twice won the "Innovationspreis der Initiative Mittelstand" in the knowledge management category (2005, 2007).
Aviation process optimization
Tools for process optimization in the aviation industry, including custom workflow and data processing solutions for ground handling and operations teams.
Technology we work with
We pick the right tools for each project. Our current and recent technology stack includes:
Frontend
React, Vue.js, TypeScript, Astro, HTML5, CSS
Backend
Spring Boot (Java & Kotlin), Node.js with TypeScript, HCL Domino
Data & storage
MongoDB, PostgreSQL, SQLite, Google Datastore, Automerge CRDTs
AI & ML
OpenAI, Google AI Studio, RAG pipelines, LLM-powered code generation
Infrastructure
Cloudflare, Docker, CI/CD, GitHub Actions
Security
End-to-end encryption, digital signatures, append-only audit logs
Latest from the blog
Technical articles, project updates, and conference talks — since 2009.
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The Haven App Builder - describe the app your team is missing, and an AI writes it
23.09.2026
Haven has been extensible through apps for a while: the MindooDB App SDK, a set of context files a coding agent can read, and a reference app to fork. That works - and it still asks you to care about where the code lives, who hosts it, and how the result reaches Haven. The new App Builder, itself an app in Haven's App Store, removes all of it. Connect GitHub, Cloudflare and Cursor once, then type a name and a few sentences about the app you are missing and press one button: the builder creates a private repository from a starter template, writes your brief into it, reserves a web address on Cloudflare, wires push-to-deploy, waits for the app to answer, hands it to Haven for installation, and sets a Cursor cloud agent to work - which you can then watch draw an icon, write the app and click through it in a browser. What comes out is an ordinary MindooDB App with its own repository and its own address, and it is safe to run because none of Haven's app isolation changed: sandboxed iframe, logical database ids, permissions you granted at install time, and a network allowlist that blocks anything the app was not allowed to call.
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Peer-to-peer sync between Haven clients - and reaching the MindooDB server in the cupboard
22.09.2026
Haven clients can now sync directly with each other over the Iroh network, with no server in the middle: two devices of the same tenant converge device to device, carry on collaborating while the server is down, and hand over the complete signed history afterwards. It arrived as the side effect of solving a duller problem. The crazy-hardware series proved that a MindooDB server fits inside a phone, an Orange Pi and a Wi-Fi router - and then left every one of them sitting at a LAN address. At Local First Conf in Berlin I watched Brendan O'Brien present Iroh: endpoints identified by public key rather than DNS name, QUIC, relays when NAT gets in the way, and a Rust library that compiles to WebAssembly. Both the MindooDB server and the Haven client now speak it, so pasting a ticket into Haven makes the box in the cupboard reachable with no DynDNS, no port forward and no certificate. And once that runtime was in the browser, peer-to-peer sync was a change of argument rather than a change of code path.
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MindooDB on crazy hardware, part three - a server inside the Wi-Fi router
12.09.2026
First an emulated x86_64 VM on an iPhone, then an Orange Pi Zero 3W with eight cores and 6 GB of RAM. This time the host is the box that was already in the room doing another job: a GL.iNet Flint 2 AX6000 Wi-Fi router - four ARM64 cores, 1 GB of RAM, 8 GB of eMMC and OpenWrt. It was the bumpiest setup of the three, and both potholes were OpenWrt's: Docker's bridge DNS could not resolve the npm registry during the build, and nftables would not hairpin the published port afterwards. Both are now handled by serversetup.sh itself. After that the server minted its identity in 1661 milliseconds, and Haven pushed a Teacher's Desk tenant to the thing that hands out our Wi-Fi.
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MindooDB on crazy hardware, part two - a whole server on 14 grams of Orange Pi
10.09.2026
Last month I ran a MindooDB server inside an emulated x86_64 VM on an iPhone: 75 minutes for the Docker build, 102 seconds for one identity. The hardware actually meant for the job has now arrived - an Orange Pi Zero 3W, 65 x 32 mm, 14 grams, eight ARM64 cores and 6 GB of RAM, $85 from Amazon and ten days lost somewhere between Dallas and Cologne. Same repository, same serversetup.sh, no changes for ARM64: the Docker build took 137.6 seconds and the server identity 649 milliseconds. Then Haven pushed a Teacher's Desk tenant to it over Wi-Fi and synced several thousand encrypted entries to a board that fits in a shirt pocket.
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Mindoo Vega grows up - Gantt charts, a real spreadsheet, and the project as it was last month
08.09.2026
Vega used to be a mind map with a Kanban board attached. It now carries a Gantt chart you can drag dates around in, a full Excel-compatible spreadsheet - the TeamGrid engine, 280 formulas, column, bar, line and pie charts - that mirrors your project nodes into cells and writes your edits back to them, and an XLSX export anyone can open. MindooDB's time travel turns into project reporting: open the plan as it stood at the kickoff, or put two dates side by side in a comparison spreadsheet where XLOOKUP has already paired the old and the new rows and the delta columns are written for you. Plus poster printing across any number of sheets with glue strips, links between nodes across maps and tenants, a dockable properties sidebar with Markdown and Mermaid, a node icon library, and better layouting. There is a new site for all of it at mindoo-vega.com.