AI and backend engineer in Prague, trained in systems programming. I build systems and study what happens inside a neural network: the systems are my work, the neural networks a serious hobby. Co-founder & CTO at Zoplio (supported by BUDETO Studio) · BSc Computer Science, Systems Programming, MFF UK (2026) · Master's in AI from October 2026.
kubadvorak.com · CV · hi@kubadvorak.com
- bitcoin-multisig-wallet: my Bachelor's thesis (100 pages on DSpace), graded Excellent. An Android M-of-N multisig wallet in which every signature is made on a Trezor via Trezor Connect; the backend coordinates the cosigners but never holds key material and never signs.
- Hand-written BIP-174 (PSBT) encoding and parsing, the multisig P2WSH script and the bech32 encoder.
- 7 Kotlin/Ktor services on PostgreSQL under Docker Compose.
- 123 backend test methods in GitHub Actions.
- A 2-of-3 transaction verified on testnet.
- Zoplio developer API (source private, surface public): API docs ·
@zoplio/sdk-js·zoplioon PyPI ·@zoplio/claude-tool. Zoplio is an AI assistant that books meetings over WhatsApp, Slack and email; it is in early access, and keys go out in waves. I wrote all of its backend, including:- the public API: keys, rate limits, usage quotas and signed webhooks;
- both SDKs (Node/TypeScript and Python);
- the hosted MCP server, so AI agents can book meetings.
- Kreedl Intelligence (private; AI Engineer at Kreedl, Jan–Jun 2026): I designed and shipped an internal Gemini pipeline for pitch-deck analysis in investment screening. Python, FastAPI, MongoDB, Docker.
- Systems programming at MFF UK (my Bachelor's specialization; course code, not public):
- a RISC-V (Sv32) teaching kernel in C, built in a team of three: heap, scheduling, synchronization, virtual memory, user-mode processes;
- a C-subset compiler to LLVM IR (flex, bison, IRBuilder);
- parallel programming with TBB, OpenMP, SYCL (CPU target), Spark and C# async, with jobs on the faculty's SLURM cluster;
- Linux Administration: QEMU/KVM VMs as systemd services, DNS with DNSSEC, backups verified by a restore.
- AntColonySimulator: a multi-colony foraging simulator in Unity/C# (solo course project, Advanced C# Programming).
- lost-in-the-monitor: can a monitor catch a hidden goal by reading a model's chain of thought? An eval harness around gpt-oss-20b, run under vLLM in single-GPU PBS jobs (and with Ollama locally). Model-written code is graded in a time-limited subprocess against public and hidden tests. Monitor scores are sampled 8 times, because they are bimodal even at temperature 0. On backdoors framed as a performance fast-path, gpt-oss-20b as a monitor caught 6% where Gemini 2.5 Flash caught 80%. My starting hypothesis, that monitoring degrades when the chain of thought is in a lower-resource language, did not survive scaling. The null is published with the pre-registration and a dated lab log.
- absorption-atlas: how a concept is carried inside Gemma-2-2B/9B depends on what kind of concept it is. Built with TransformerLens, SAELens and Gemma Scope, in GPU jobs on MetaCentrum; 15-page technical report.
- superposition-phases: when a layer computes more functions than it has neurons, the superposed code grows continuously out of the dedicated-neuron solution. The public code is the preliminary first pass; the 256-job CPU sweep and the 40-page write-up (in review) are not public yet.
Day to day I build with Claude Code: I write a short spec first, keep each change small and read every diff before it goes in. The thesis wallet and my kernel code I wrote almost entirely by hand.