Marvin Heyne
DE CV Contact

Marvin Heyne · software engineer · HPI Potsdam

I build agentic-AI systems that have to survive real users.

Voice agents for 100+ salons at MitJulia1, IT-Systems Engineering at HPI (GPA 1.44), and until October Founding Engineer at Kobe AI2.

Email Marvin CV (PDF) GitHub ↗ LinkedIn ↗

Figures

each with date and source
  1. MitJulia · Nov 2026 100+1 salons whose calls a voice agent I ship on answers
  2. Kobe AI · Oct 2026 ~4702 commits in three full-time weeks as Founding Engineer
  3. DFL × AWS · Apr 2025 423 teams at the first Bundesliga Hackathon; one of the winning teams
  4. HPI · 108 ECTS 1.44 GPA; Software Architecture and Software Engineering both 1.0

Case files

two products, one research project, two wins
All projects with previews →
Case 01 MitJulia (formerly Friseurtelefon) Software Engineer · since Jan 2026

A voice agent that answers salon phones

Julia picks up 24/7 and books straight into the salon’s booking system.

Show what I doHide what I do3
  • Product issues end to end: reproduce on a real transcript, check every salon, ship the PR.
  • Test suite for the voice agent grown from 67 to 267 cases.
  • 434 commits in the monorepo, Aug – Nov 2026.
  • TypeScript
  • AWS Lambda
  • ElevenLabs
  • Twilio
Fig. 2.1 · Live demo A call to Julia on the left, the salon dashboard on the right. Pick a slot yourself while Julia offers times.
Live call

Sat 7:42 pm · outside opening hours

Sophie Regular client · recognised 01:12

Julia is listening

Init webhook · client recognised: Sophie

Hi Sophie, this is Julia, the digital receptionist at Sample Salon. How can I help?

Hi! I need an appointment next week, ideally Tuesday after work.

Sure. Wash, cut and blow-dry with Mia again?

Yes, exactly.

get-appointment-availabilities · Tue · Mia → 2 slots

On Tuesday Mia is free at 17:30 or at 18:30. Which suits you better?

18:30 is perfect.

create-booking → appointment-booked

Done. Your appointment is on Tuesday at 18:30 with Mia. See you then!

Thanks, bye!

Last 7 days

Revenue

TotalOutside opening hours 2,846 € 612 €

Bookings

TotalOutside opening hours 47 11

Calls

TotalOutside opening hours 1299Σ 2:41h · Ø 75s 31

Booking system · Tuesday

Julia books straight into the salon’s own booking system.

MiaJana 16:0016:3017:0017:3018:0018:3019:0019:30 ColourCutCutHighlightsColourUpdo

Calls

DateTimeDurationNameCall reasonCall resultBooked revenue
Sat17:580:48Paul Change Appointment moved–
Sat16:121:31Emma Transfer Transferred–
Sat14:400:36Unknown Price Information given–
Demo with sample data
Case 02 Kobe AI Founding Engineer · Mar – Oct 2026

Kobe AI, your personal superconnector

Finds the warmest path to the person you need, through your own network.

Show what I builtHide what I built4
  • Backend on Cloudflare Workers with Hono and Postgres row-level security.
  • Extended the MCP server our CTO had set up (27 of 89 commits), and the Electron desktop client.
  • Co-developed a six-stage agent pipeline in Python (Claude Agent SDK).
  • Releases 1.1.49 and 1.1.50, in a team of three.
  • TypeScript
  • Cloudflare Workers
  • Electron
Fig. 2.2 · Live demo Kobe web app, “Start Mission”: rebuilt from the product prototype, sample network and contacts.

Ask Kobe

Your personal Superconnector

Demo with sample data
Case 03 Jugend forscht Research · 2023 – 2025 State winner

PneuNet, a CNN written from scratch

Built in NumPy first, then seven architectures benchmarked in PyTorch.

Jugend forscht 2024: Thuringian state winner and a special prize at the national final.

  • Python
  • NumPy
  • PyTorch
Fig. 2.3 · Live demo The DICOM viewer from PneuNet, rebuilt: open a study, window/level, zoom and measure in mm, segmentation, the AI’s second opinion and the CAM heatmap. Sample X-rays from the RSNA Pneumonia Detection Challenge (2018); overlays partly illustrative. Not a diagnosis.

Not a diagnosis · research prototype

6Class activation mapping shows where the ResNet-34 looked: 7 × 7 grid from the last conv layer, upsampled and coloured. Drag the opacity slider.

Images: sample DICOMs from the public repo, RSNA Pneumonia Detection Challenge (2018) / NIH ChestX-ray14, label “Lung Opacity”. Detection on image 1 and the lung mask on image 3 are traced from the viewer screenshots in the repo; all other overlays and every CAM heatmap are illustrative, because the model weights are not public.

Demo with sample data
Case 04 Launchpad by Stan · Pennsylvania Startup competition · Oct 2026 Winner

Won Launchpad with Kobe

30 teams from ~700 applications. I kept shipping Kobe and built the pitch deck in a day.

Case 05 DFL × AWS × EintrachtTech Hackathon · Apr 2025 Winning team

Bundesliga Hackathon 2025

A fan app with an AI chat on AWS. Team of three; I owned the repo.

teams
42
in the final
15
winning teams, one of them ours
6
  • Expo
  • React Native
  • AWS
Fig. 2.5 · Live demo The Expo app from the Bundesliga hackathon, rebuilt from its code. The AI chat works (FAQ, word completion, quiz, read aloud, share); the other tabs are previews with invented clubs. The AWS backend is off, so answers are samples.

FAQs

Demo with sample data

Commit ledger

from the repositories, author commits only
Commits in a stretch of work
  1. Kobe AI, Oct 2026 477 commits
  2. MitJulia, Aug – Nov 2026 434 commits
  3. Voya hackathon, 48 h 130 of 142 commits
  4. takeøff website, 5 days 32 of 33 commits

Author commits only; AI-assisted commits attributed to agents are not counted. Private repositories are described, not linked.

Authored share per project
  1. PneuNet 2025 100% 60 of 60 commits
  2. Bundesliga fan app 2025 20% 18 of 89 commits
  3. Voya 2026 92% 130 of 142 commits
  4. takeøff website 2026 97% 32 of 33 commits
  5. Sicily trip planner 2026 · solo 100% 51 of 51 commits
  6. Thesinator 2026 19% 5 of 27 commits
  7. ¡Vamos! 2026 · solo 100% 34 of 34 commits
  8. OweFlow 2025 36% 43 of 120 commits

Parsed from the “X of Y commits” line of each project. Solo projects are 100 %.

Positions

month axis, Oct 2024 to Nov 2026
Full experience →
  1. HPI B.Sc. IT-Systems Engineering Oct 2024 – 2028 (expected)
  2. Leona Research Solution Engineer May 2025 – Sep 2025
  3. MitJulia (formerly Friseurtelefon) Software Engineer, AI Voice Agents Jan 2026 – ongoing
  4. HPI Engine Student Associate, Startup Tours Feb 2026 – ongoing
  5. Kobe AI Founding Engineer Mar 2026 – Oct 2026

Project index

filter by field
All projects with previews →

14 of 14 shown

Project index
Year Project Kind Field Evidence Code
2025 PneuNet Pneumonia detection on chest X-rays, from a NumPy CNN to a DICOM viewer. Research Machine learning >87% classification · >95% segmentation GitHub ↗
2026 ESN Event Hub Process analysis and a small web app for Erasmus Student Network Potsdam. Course project Web Team of five · grade 1.3 pending
2026 MediaSync Android backups to a USB stick, no cloud. App Mobile Solo · about 26k lines of Kotlin pending
2025 Bundesliga fan app Fan app with AI chat on AWS; winning team. Hackathon Mobile, Agentic AI Repo owner · 18 of 89 commits GitHub ↗
2026 GorillaScout Bachelor's project on re-identifying wild gorillas from camera-trap video. Bachelor's project Machine learning Ongoing · team of eight GitHub ↗
2026 Agentic product with BMW An agentic system that spots early warning signs of unplanned machine stops. Course project Agentic AI Ongoing · team of six · under NDA pending
2026 Voya Agent that matches founders with co-founders and investors, with a voice role-play. Hackathon Agentic AI, Web Technical lead · 130 of 142 commits GitHub ↗
2026 takeøff website Bilingual site for a student cultural collective, Canvas scenes, no tracking. Website Web 32 of 33 commits in five days GitHub ↗
2026 Sicily trip planner Planning tool a group of five actually used for a trip. Tool Web Solo · 51 commits GitHub ↗
2026 Thesinator AI-guided thesis journey: matching, future simulation, voice. Hackathon Agentic AI, Web +10,546 lines in 5 of 27 commits GitHub ↗
2026 PowerSqueak Brownfield work on a seven-year-old Smalltalk presentation tool. Course project Software engineering 38 commits · ~4,800 lines · grade 1.0 GitHub ↗
2026 ¡Vamos! Offline Spanish app with spaced repetition and a browser-side AI tutor. Tool Web Solo · 34 commits in two days GitHub ↗
2025 OweFlow Flutter app for splitting group expenses; I owned auth. App Mobile 43 of 120 commits GitHub ↗
2026 TouchdownTactics Real-time strategy game in Squeak/Smalltalk; I owned the cards and the elixir. Course project Software engineering 38 commits · team of seven · grade 1.0 pending

Awards register

newest first, participation listed as such
All awards →
Awards register
DateResultEventPlace
Oct 2026 Win Launchpad by Stan Winner on Demo Day6 † Result as announced to the teams; written confirmation pending. Pennsylvania, USA
Sep 2026 Participation OpenAI Hackathon at IdeaLab! 2026 Participant Vallendar
Jun 2026 Win AWS World Sports Innovation Cup 2026 Winning team7 † Result as announced to the teams; certificate pending. Frankfurt
Mar 2026 Participation START Hack 2026 Participant St. Gallen
May 2025 Win Siemens × AWS Hackathon “ReThink Recycling” Winning team7 † Result as announced to the teams; certificate pending. Berlin
Apr 2025 Win Bundesliga Hackathon 2025 Winning team Frankfurt
Dec 2024 Prize E-Challenge, HPI Engine Best Pitch 2024 Potsdam
Jul 2024 Win JugendUnternimmt Summer School First place, pitch competition Erfurt
Feb – Jun 2024 Win Jugend forscht 2024 Thuringia, plus the DGUV special prize at the 59th national final Weimar · Jena · Heilbronn
until 2024 Prize German Karate Championships (DKV) U14 vice-champion and U21 team bronze —
Jun 2024 Prize MINT-EC certificate With distinction —
2022/23 and 2023/24 Prize Bundeswettbewerb Informatik First prize in round 1, twice —
Nov 2023 Win Computer Science Team Competition of Thuringia's STEM schools First place Jena

† As announced to the teams; written confirmation pending.

Method

how the work gets done
Full story →

Before I change a product I reproduce the problem on a real transcript and sweep every configuration in the fleet. Defaults stay conservative, per-customer opt-in rather than global switches. Every hand-over names what I did, what I did not do, and what could go wrong, written so that a non-engineer can follow it.

I grew up in Erfurt, went through a specialized STEM school and the federal computer-science competition, and moved to Potsdam for HPI in 2024. I work in focused sprints and use AI coding agents heavily, and say so: the architecture decisions, the test strategy and the review are mine.

  1. 3,200 / 0 comparisons on 400 generated catalogs against an independent re-implementation, 0 deviations Evidence before code I reproduce a problem on a real transcript and check every configuration before I change anything.
  2. 32 in 5 days commits on the takeøff website; 477 at Kobe in October 2026 Focused sprints Short, intense build phases with a clear goal, then review and clean-up.
  3. 8+ projects with written agent contracts (AGENTS.md, CLAUDE.md) Agents, openly I use AI coding agents heavily and say so. The architecture decisions, the test strategy and the review are mine.

Now open entries

  1. since Oct 2026Bachelor's project GorillaScoutTeam of eight at Prof. Gerard de Melo's AI chair: a multi-year pipeline that detects, tracks and re-identifies wild gorillas in camera-trap video.
  2. since Aug 2026Product issues at MitJuliaEnd to end, from fleet-wide analysis to the pull request.
  3. 16–19 Nov 2026HPI Engine startup tour to ZurichOrganizing company visits, participant selection and budget.
  4. winter 2026/27Seminar with BMW on agentic productsDetails under NDA.

Blog

notes written after each event
All posts →

  1. Deep learning without the exam: why I rebuilt the course book as a website

    This term I'm sitting in on the Deep Learning lecture at HPI. To really understand the material, I rewrote the first part of the course book as a simplified German study site with interactive demos.

    Interim update, written during the term.2 min read

  2. An agentic system with BMW: the code calculates, the model explains

    In the seminar Building Agentic Products we're working with BMW on a system that spots early warning signs of unplanned machine stops. An interim update, as abstract as confidentiality requires.

    Interim update, written shortly after the first interim review.3 min readLive demo

  3. GorillaScout: getting into a pipeline that four cohorts built before us

    Since October I've been in the bachelor's project that re-identifies wild gorillas in camera-trap video. An interim update on how you get into a pipeline that four cohorts built before you.

    Interim update, written in the project's first month.3 min readLive demo

Field photos

captions as recorded
Marvin at a desk in the build hall, thumbs up
Fig. 1 Build hall at Launchpad, Pennsylvania
Northern lights over a snowy forest, two people in the foreground
Fig. 2 Northern lights on the van trip to the Arctic Circle
Marvin on a ladder rigging lights and cables on a club stage
Fig. 3 Stage build for a takeøff night
Marvin pitching on a stage in front of a screen
Fig. 4 On stage

Contact

answers within a day or two

Internship, project or exchange semester: write to me.

Open for internships, full-time April to September 2027, and an exchange semester planned for winter 2027/28.

Email Marvin marvin.heyne@student.hpi.uni-potsdam.de CV (PDF)

Sources

for every numbered claim on this page
  1. [1]MitJulia, formerly Friseurtelefon: 100+ salons live as of November 2026 (figure as published by the company); 434 commits in the monorepo, August to November 2026.
  2. [2]Kobe AI, October 2026: 297 of 894 commits in the main repository, 157 of 750 in the desktop repository, 18 of 21 in the pitch deck and 5 of 263 in kobe-eve (about 477 in total, counted with two of my git identities); counted across all three, the v3 repository has 509 of 918 (5 Nov 2026). Releases 1.1.49 and 1.1.50.
  3. [3]Bundesliga Hackathon 2025, DFL × AWS × EintrachtTech: 42 teams, 15 in the final at Deutsche Bank Park, Frankfurt; six winning teams named by the DFL, no ranking among them.
  4. [4]HPI transcript of records, 22 October 2026: 108 ECTS, GPA 1.4 on the German scale where 1.0 is best; both named courses graded 1.0.
  5. [5]PneuNet validation on the project's own split (above 87 percent classification, above 95 percent segmentation); Jugend forscht 2024, Thuringian state round and national final.
  6. [6]Launchpad by Stan, October 2026: 30 teams selected from about 700 applications; the win and the USD 100,000 prize are as announced to the teams, written confirmation pending.
  7. [7]Siemens × AWS Hackathon 2025 and AWS World Sports Innovation Cup 2026: results as announced to the teams; certificates are being collected.