• Markus · solo studio · Düsseldorf

Code that runs deep.

Codevena — from vena, the vein. Fullstack, DevOps and AI integration from one pair of hands: shipped, deployed and operated by one person — from edge games on Cloudflare to realtime platforms on own metal.

10
Products shipped
95+
Lighthouse mobile
99.97%
Uptime
Edge → Metal
Stack breadth
§ 01 — Principles · operating manifesto

How I build.

Infrastructure is chosen per problem. No one-stack ideology, no framework gymnastics.
P/01 · EDGE
Edge-native where it wins.
Own hardware where it matters.
P/02 · SIMPLICITY
Vanilla JS and static files beat most framework gymnastics.
P/03 · OWNERSHIP
Ship end-to-end.
No front-end-only excuses.
P/04 · PRAGMATISM
Infrastructure chosen per problem — no "one-stack" ideology.
§ 02 — Live products · production traffic

10 things, shipped.

Each product: Design, Build, Deploy, Operate. Solo. From edge games to realtime multilingual platforms.
01

Flashbuddy

flashbuddy.app · production SaaS

Complete learning SaaS — FSRS spaced repetition, AI flashcards, gamification, Stripe with 4 tiers and idempotent webhooks.

Next.js 16 · Prisma 6 · Postgres · Stripe · OpenAI · Coolify
02

Capypad

capypad.com · bilingual SaaS

Bilingual SSR code quiz for 10 languages. pgvector-HNSW dedup on insert, hardened admin content-push API.

Next.js 16 · Drizzle · Postgres + pgvector · NextAuth v5 · Coolify
03

AzadiFeed

azadifeed.com · realtime platform

Realtime crisis feed for the Iranian diaspora. Trilingual with full RTL support, Socket.IO live stream.

Next.js 15 · MongoDB · Socket.IO · OpenAI · Telegram
§ 03 — Offer · Production Sprint

One flow. Production-ready.

For startups and product teams with a clearly named bottleneck and no senior capacity free to close it.
CODEVENA / PRODUCTION SPRINT

One critical product flow. Live in three weeks.

A flow is one path that works on its own: the checkout, the onboarding journey, AI search across your documents. I own it from the technical decision to a running deployment — no handoff ping-pong, no open-ended feature bucket.

A FIT WHEN
  • a concrete MVP, modernization, or AI flow is stuck
  • you need end-to-end ownership instead of more coordination
  • the result must actually run in production after the Sprint
IN THE SPRINT
  1. 01Written scope and architecture decision
  2. 02UX and full-stack implementation
  3. 03Tests, review, and security baseline
  4. 04Deployment, monitoring baseline, and handoff docs

One flow, not an open wishlist. 24/7 operations, data migration, content, and external provider costs are excluded unless explicitly scoped. For the three weeks to hold, I need all required access at kickoff, one contact who can decide, and responses within 24 hours.

DURATION
3 weeks
FIXED PRICE
€5,900 excl. VAT
OWNERSHIP
1 accountable builder
Request a Sprint in writing

Sprints are booked in advance. Next open slot: from April 2027 — earlier dates by written arrangement only.

Send the problem, current state, and deadline — I reply with fit/no-fit and a fixed scope.

§ 04 — Stack · working toolchain

The toolchain.

What's in daily use. Chosen per problem, not per ideology.
Frontend / UI
/01
  • Next.js 13/14/15/16 · React 19 · TS
  • Tailwind v4 · shadcn/ui · Radix · Motion
  • Vanilla JS · HTML5 Canvas · 60 Hz fixed-step
  • Three.js · Shaders · Bloom · 20k particles
  • Axe 0 serious/critical · Playwright E2E
Backend / Runtime
/02
  • Node.js · Express · Server Actions
  • Auth.js · GitHub OAuth · Allowlist
  • Prisma 6.x + PostgreSQL 16
  • MongoDB · SQLite · Supabase
  • WebSockets · Socket.IO · Durable Objects
Edge / Cloudflare
/03
  • Pages · Workers · D1 · R2
  • Durable Objects (stateful rooms, hibernation)
  • Zero-origin for games & static-first
  • Presigned PUTs · S3-compatible
Self-Host / DevOps
/04
  • Hetzner dedicated · hardened Ubuntu
  • Coolify · Docker · compose · standalone
  • GitHub webhooks · blue-green deploys
  • Tailscale mesh-VPN · fail2ban · auditd
  • BorgBackup · GitHub Actions · Sentry
  • Umami (self-hosted analytics)
AI Integration
/05
  • OpenAI · Real-time classify + translate
  • Claude + MCP · FS · render tools
  • OpenRouter · cost-/model-flexible
  • Metadata enrichment pipelines
Quality / Security
/06
  • Vitest + Testing Library · Playwright
  • ESLint strict · --max-warnings=0
  • TS strict · noUncheckedIndexedAccess
  • Allowlist-auth · defense-in-depth
  • Append-only audit log · diff compute
§ 05 — ai workflow · reviewgate

AI in the bloodstream.

Agents write along. Only what survives the review panel gets merged.

I build with agents — and own the result.

Claude Code runs in the workflow daily. ReviewGate — my own review system — spawns a heterogeneous reviewer panel of Codex, Gemini and Claude for every feature, aggregates the findings and blocks the merge until everything is fixed. No unreviewed AI code in production.

Spec → 2 independent review agents
Plan → subagent-driven development
ReviewGate: Codex · Gemini · Claude → PASS
PR → explicit OK → merge
Deploy verification on production
§ 06 — Origin · trajectory

The long path.

From VB.NET bots to edge-native apps. The detour was the way.
Started at 18 with VB.NET bots for Final Fantasy XI. Long Python detour. 2024 — rediscovery in the AI era. Since then: Solo, by design.
◦ 18 / ORIGIN
VB.NET · Final Fantasy XI
First lines of code were game bots. Packet-sniffing, state machines, schedule loops — before I knew what those things were called.
◦ PYTHON ERA
The long detour
Years of scripting, data pipelines, automation. The hard discipline: things that run in the dark, alone, unattended.
◦ 2024 / REDISCOVERY
AI era · ship loop
From single-feature prototypes to end-to-end ownership. Edge architectures, self-hosting, AI integration as first nature.
◦ 2026 / NOW
10 Products · Live
Edge games, realtime feeds, AI agent runtimes, retro game libraries. 1–2 consulting slots per quarter.
§ 07 — Meta · how the site runs

How Codevena runs.

Hetzner + Coolify + Tailscale as home base. Cloudflare Edge for games. Coolify-orchestrated Docker DBs (Postgres · Mongo · Redis).
CASE STUDY · SYSTEM TOPOLOGY

Edge to metal. And back.

Each product picks its substrate: zero-origin for games (CF Pages + Worker + D1), Next.js + Prisma + Postgres on Coolify behind Traefik (Letsencrypt) for portfolio + CMS sites, Durable Objects for stateful rooms.

Architecture diagrams are abstracted — no hostnames, ports, or versions public. Defense-in-depth via DB re-reads on every server action. Append-only audit log with diff computation.

edgemetal◦ LIVE · ~42 rps
[ EDGE ] cloudflare
[ PROXY ] traefik
CODEVENA.DEV
[ METAL ] hetzner
[ MESH ] tailscale
◦ CONTACT · PROJECTS

A project that needs someone to end-to-end operate it?

[email protected]

Written inquiries only. No calls, no Calendly. One sentence on the problem, one on the scope, one on the timeline — and we're talking.

01 Fullstack02 DevOps03 AI Integration04 1–2 engagements · quarter05 Düsseldorf / remote