Available for B2B contract projects · Remote
ENPL
$ ~/dolchon.dev $ whoami

Hi, I'm Michał.
I build apps that scale.

Michał Dołchoń · Backend Developer

Backend systems that scale, APIs that don't break, and infrastructure you can trust - architected, built, and operated end-to-end.

  • > Systems that break under load?
  • > Cloud costs that surprise you?
  • > AI features stuck in "almost ready"?
Talk to me
Poland
--:--:-- CET
//core
TypeScript Node.js NestJS Go Python
//ai
AI Agents RAG MCP LangChain LangGraph LlamaIndex Local LLMs (Ollama, Llama) Speech AI (Whisper, Coqui STT, Vosk)
//cloud
Docker Kubernetes Terraform AWS Azure Cloudflare Workers CI/CD
//data
PostgreSQL MongoDB Redis Kafka RabbitMQ
//arch
Microservices Event-driven WebSockets OpenTelemetry
//also
PHP / Laravel Kotlin Svelte React n8n Web3

Why me.

Backend developer: TypeScript, NestJS and Go on PostgreSQL and MongoDB - APIs and microservices that hold up under real traffic.

7+
Years of Experience
4+
Years in Production Backends
30+
Production Services Delivered
15k
Concurrent Users Served
// CODING PROD_READY
Illustration of Michał coding
> shipping_daily.sh
[01]

Production-Ready

4+ years of production backends: 15k concurrent users, zero downtime with blue-green deployments, systems that passed rigorous security audits. 7+ years of coding overall

[02]

Core Stack

TypeScript, Node.js, NestJS and Go on PostgreSQL, MongoDB and Redis. PHP, Kotlin and Python when the project calls for it

[03]

Bleeding Edge

LLM agents and RAG in production, on-premise AI on edge devices, and a pioneering zk-SNARK implementation for smart-contract privacy

[04]

Cloud & DevOps

AWS, Azure, Terraform, Docker, CI/CD, Grafana, New Relic - infrastructure as code, blue-green deployments, production monitoring

About me.

A quick, concrete overview of how I work and what you get when we collaborate.

Ownership & delivery

I take work from idea to production: clear scope, reliable rollout, and a stable system afterwards.

Pragmatic engineering

Clean architecture where it matters, fast iteration where it helps - with tests, docs, and sane defaults.

Production mindset

Observability, cost-awareness, and reliability are part of the feature, not an afterthought.

Case studies

A few real examples: the problem, the approach, and the outcome.

AI assistant backend from scratch (Vaiot.ai)
API · Integrations · Data pipelines · Production rollout
▾
// Problem
Deliver a reliable backend for an AI assistant with multiple integrations and evolving requirements.
// Approach
  • > Designed API boundaries, validation, authentication, and integration points
  • > Implemented data ingestion/sync with idempotency and retries
  • > Added observability (logs/metrics) and deployment automation
  • > Integration of Azure CLU and OpenAI with RAG
// Outcome
  • > Faster iteration without breaking production
  • > More predictable deployments and easier debugging
  • > A base architecture that scales with new features
TypeScript Node.js Redis Docker Cloud CI/CD
Unified email delivery service (Vaiot.ai)
Multi-project platform · Cost control · Deliverability
▾
// Problem
Multiple products needed email sending with consistent templates, tracking, and lower costs.
// Approach
  • > Built a shared service with standardized templates and routing
  • > Added queues/retries and monitoring for deliverability issues
  • > Provided a simple API so teams could integrate quickly
// Outcome
  • > Reduced duplication across projects
  • > Improved reliability of notifications
  • > Lowered operational overhead and vendor dependence
Node.js TypeScript Nest.js GraphQL Queues Observability
Cash payments in IoT vending machines (Selfibox)
Hardware integration · Edge constraints · Reliability
▾
// Problem
Implement a robust cash payment flow across devices (acceptors, receipts) in the field.
// Approach
  • > Modeled device state machines and failure scenarios
  • > Implemented safe retries and reconciliation for transactions
  • > Integrated receipt printing and end-to-end monitoring
// Outcome
  • > More stable on-site sales flows
  • > Fewer manual interventions for operators
  • > Clearer incident diagnosis when devices misbehave
MQTT Redis TypeScript Nest.js PHP IoT
Payment gateway: crypto + Stripe + Przelewy24 (Vaiot.ai)
Unified payments · Webhooks · On-chain integration
▾
// Problem
Support multiple payment providers (crypto + card + local transfers) with a consistent status model, safe retries, and direct blockchain integration.
// Approach
  • > Implemented a unified payment abstraction (create/confirm/refund) across providers
  • > Handled webhooks with signature verification + idempotency keys to prevent double-processing
  • > Integrated on-chain confirmation directly into the gateway (smart-contract events → payment status)
  • > Added reconciliation and alerting for mismatched states and edge cases
// Outcome
  • > Fewer payment-related incidents and faster debugging
  • > Consistent payment UX across products and teams
  • > Safer rollouts with deterministic retries and audits
TypeScript Nest.js Node.js Stripe Przelewy24 Webhooks Redis Smart contracts
DDRS backend (Vaiot.ai)
Integrations · Data sync · Reliability
▾
// Problem
Build and evolve a production backend with external integrations and frequently updated domain data.
// Approach
  • > Designed APIs and data flows with caching and rate limiting where needed
  • > Implemented robust sync jobs (retries, backoff, idempotency) for external data sources
  • > Improved observability and operational readiness (dashboards, alerts)
// Outcome
  • > More stable operations under changing data and integrations
  • > Lower mean time to detect/resolve incidents
  • > A maintainable platform for further feature development
TypeScript Nest.js Node.js Redis Integrations Monitoring
On-prem AI for kiosks: vision + voice + RAG agents (Selfibox)
Computer vision · STT/TTS · RAG · Edge / on-prem
▾
// Problem
Add reliable AI features to kiosk workflows under edge constraints (latency, offline tolerance) while keeping operations predictable.
// Approach
  • > Implemented vision processing with YOLOv9 for detection/verification in the flow
  • > Added speech-to-text via faster-whisper and text-to-speech via XTTSv2 + Chatterbox for natural interactions
  • > Built AI agents with RAG using Gemini 2.5/3; embeddings via granite-embedding:278m and multilingual-e5-base for fast local retrieval
  • > Designed the architecture for on-prem deployment: cache, retry, and observability for operators
// Outcome
  • > Full voice support and user guidance through fortune-telling flows
  • > Greater automation and fewer manual interventions
  • > More stable operation thanks to edge-friendly architecture and monitoring
YOLOv9 faster-whisper XTTSv2 Chatterbox Gemini 2.5/3 RAG granite-embedding:278m multilingual-e5-base

FAQ

Frequently asked questions about working together.

What kind of projects are you a best fit for? ▾
Fullstack contract projects where you want someone to fully own APIs, integrations, cloud, and production operations - taking work off your plate instead of adding management overhead.
How do you communicate progress? ▾
Short written updates, clear milestones, and early risk flags - so you always know what is shipped, what is in progress, and where I need input, without micromanagement.
Do you work well with existing codebases? ▾
Yes - I focus on safe, incremental improvements: refactors with tests, improved observability, and cleaner boundaries, while respecting existing constraints and team conventions instead of pushing risky rewrites.
What do you need from the team to be effective? ▾
Clear priorities, access to environments/metrics, and a feedback loop with product and stakeholders. Beyond that, I work autonomously and protect your time, bringing you options and trade-offs instead of raw problems.
What kind of projects energize you? ▾
Systems with real constraints: scale, reliability, integrations, privacy/security, and AI/LLM features that ship - especially where a senior engineer can take long-term ownership and become the go-to person for that area.
How do you work with non-technical stakeholders or clients? ▾
I translate technical constraints into clear options, risks, and impact on timelines or budget. With clients and product, I focus on "what problem are we solving" and propose pragmatic solutions instead of throwing jargon.
Can you support hiring or vendor decisions? ▾
Yes - I can help design practical coding tasks, participate in interviews, review architectures, and give you a second opinion on vendors or proposals, focusing on long-term maintainability and total cost of ownership.

If you need someone who can architect, build, and operate production systems - I’m a good fit.

Let's talk

Experience.

From blockchain to IoT, AI to cloud infrastructure - real production systems at scale

  1. Wandlee

    2026 – Present
    AI · Healthtech · VoIP

  2. VAIOT

    2023 – 26
    Blockchain · AI · Legal Tech

  3. RSvend / Selfibox

    2022 – Present
    IoT · Vending Machines · AI

  4. Redigo

    2020 – 22
    Web · Desktop Applications
  5. </>

    Freelance

    2018 – 21
    Web · Consulting

Client work.

Websites I have designed and built for clients.

client/goldEngine 2026

Gold Engine

Website for a car workshop near Głubczyce: mechanics, chiptuning and servicing. Fast static site with local SEO (schema.org AutoRepair), click-to-call contact and a photo gallery.

Astro Cloudflare Local SEO
Visit site →

// Need a website for your business? See the offer →

Side Projects.

Beyond work hours - exploring new technologies and building for fun

project/crochetIt BUILD_1

Crochet It

Mobile app for tracking crochet project progress. Published on Google Play

Dart Flutter Mobile
Google Play
project/??? BUILD_2

Coming soon

Something new is in the works - details will show up here soon.

// IN_PROGRESS

project/??? BUILD_3

Coming soon

Something new is in the works - details will show up here soon.

// IN_PROGRESS

project/??? BUILD_4

Coming soon

Something new is in the works - details will show up here soon.

// IN_PROGRESS

After hours.

Beyond the terminal - what keeps me inspired when the laptop closes.

Chief Happiness Officer: Bug inspector & head of emotional deployment.
01 // CAT_OPS [01/04]
Chief Happiness Officer

Chief Happiness Officer

Bug inspector & head of emotional deployment.

02 // SOUND [02/04]
Music Production

Music Production

Analog synths, grooveboxes & late night mixing.

03 // CAT_OPS [03/04]
Senior Code Reviewer

Senior Code Reviewer

Demanding treats before approving production merges.

1 / 4
> drag / swipe or use ← → keys

You made it to the end. Let's start something.

Backend, AI agents, integrations or a technical consultation - available for B2B contract work, remote.

$ contact.sh
> ESTABLISHING_B2B_CHANNEL --remote --secure
Email
••••••••••••••••
Phone
••••••••••••••••
Location
Prudnik, Poland
LinkedIn
michaldolchon

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