Gregor Welters DE Get in touch Contact
01 — Diagnosis

So you're a
token maxxer?

Always the newest model. Maximum context. Highest reasoning tier. Because you know quality comes from the intelligence behind it.

02 — Consequence

Then hire
the strongest model
on the market.

Human intelligence. 44 years of pre-training, fine-tuning and alignment since the age of ten, in a self-reinforcing learning loop across very different environments. Context window: entire system landscapes. Hallucination rate: pleasantly low.

Gregor Welters — Solingen, Germany

Senior AI Software Engineer
& Software Architect

Agentic coding demands entirely new skills and approaches. Those who master them turn AI into a productive lever for their own creativity, instead of constantly producing new, often hidden problems.

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Work

Five cases

Five examples from my work that speak for themselves. The full career history is in my CV.

Open-heart surgery

The company's core component, the bet settlement on which all of its revenue depends, was extremely slow and outdated.

Correctness under loadPrecisionEfficiency

From 20 minutes to under half a second

Situation
Settling and booking thousands of bet slips across 80 bet types often took up to 20 minutes per race. The reason was simple: every bet slip was evaluated individually.
Approach
Rebuilt the core component in PHP and Symfony on Clean Architecture and SOLID, fully test-covered. New approach: per race and bet type, generate just one update query that updates all affected bet slips at once. The result is extremely complex SQL update queries, performance-optimised as they were developed. Staged rollout per bet type: each only after a purpose-built, snapshot-based functional test system had proven correctness, including every edge case. This "car" was completely replaced step by step while it was driving. Without AI.
Result
Roughly 100 milliseconds per race instead of up to 20 minutes — 12,000x faster.
Role
Senior Developer, Accendere GmbH
Stack
  • PHP
  • Symfony
  • Clean Architecture
  • SOLID
  • MariaDB
  • kubernetes
24-hour on-call duty abolished

A developer had to be reachable around the clock to clean up the consequences of unfixed bugs directly in the production database.

AnalysisPersuasivenessResponsibilityEffective solution

An on-call duty that became unnecessary

Situation
A developer had to be reachable around the clock to clean up the consequences of unfixed bugs directly in the production database. This led to additional absences of colleagues because of weekend compensation days. The problem became clear to me soon after I was hired. Team leadership was under heavy pressure to innovate from management, which had for years consistently prioritised new development over bug fixing. It was a deadlock. The team was extremely unhappy.
Approach
I analysed processes and information flows, then made sure the team shared the same understanding of the problem, its causes and the right solutions. With that backing we were able to convince management of my package of measures. Afterwards we finally eliminated all the bugs at the root, one after another, as it should be.
Result
A few months after implementation the on-call duty was obsolete.
Role
Motivator, moderator, ENFP, Senior Developer
Stack
  • Jira
  • Team enablement
  • Responsibility
Customer billing rescued from collapse

The code was thoroughly rotten and no longer maintainable. A junior developer was out of their depth. The rescue: Senior Dev Man

Domain complexityLegacy replacementSOLIDExtensibilityPerformance

Report generator for around 30 parameterised report types

Situation
An important tool for billing the various partner businesses had been developed by inexperienced juniors, leaving the code thoroughly rotten and no longer maintainable. Apart from the pitiful performance, you couldn't touch it with a barge pole any more.
Approach
Rebuilt in PHP and Symfony with clean code and SOLID for around 30 parameterised report types: Instead of analysing the code to find out what it does, I simply rebuilt the application: I only examined and reproduced the output formats and the data retrieval, and rebuilt them highly efficiently in a perfect SOLID architecture.
Result
This allowed unlimited extensibility from the start and triggered a feature explosion. Since performance also improved by indecent orders of magnitude, the component could be expanded into a flexible financial database reporting tool within our service-based system architecture. Runtime, code quality and feature set clearly improved, business logic testable for the first time; the software has been continuously developed ever since.
Role
Senior Developer, Accendere GmbH
Stack
  • PHP
  • Symfony
  • SOLID
  • MariaDB
  • Clean Code
Industry CRM owned end to end, from idea to operations

Design, development and operation of a multi-tenant CRM for estate agents: mobile data capture, automated email processing, imports and exports, document generation, case and client management, API integrations. Sole developer and system administrator.

End-to-end ownershipCreativity

An industry CRM from a single source

Situation
Estate agents needed a domain-specific, multi-tenant CRM.
Approach
Design, development and operation from a single hand: mobile data capture, automated email processing, imports and exports, document generation, case and client management, API integrations.
Result
A CRM from idea to operations, built and administered by a single developer.
Role
Head of development, PHP developer and system administrator, Maklerkanzlei CEO Deutschland GmbH
Stack
  • PHP
  • Mysql
  • Apache
  • Linux
  • Symfony
  • Javascript
Own application platform

In my freelance work from 2003 to 2013 I built and operated my customers' projects on my own application platform, based on a native LAMP stack. It shows my affinity for complex and sustainable solutions to problems.

ReusabilityOwn frameworkEarly innovation

Multi-tenant application platform with CMS

Situation
My customers needed up-to-date or dynamically maintainable web presences: industrial auctioneers, tool and screw wholesalers, investor-relations service providers.
Approach
Development of a multi-tenant, LAMP-stack-based platform that let me build customer-specific developments in a reusable, modular way, so every customer benefited from synergies.
Result
Wheels only need to be invented once.
Role
Entrepreneur, lead developer
Stack
  • PHP
  • Mysql
  • Apache
  • Linux
  • Javascript
  • Java
How it gets built

This website is an example of my workflow

In the age of agentic coding, what matters is using resources efficiently and staying in control.

Gregor Specifier agent Implementer agent Test suite Maintenance agent Production Deploy
  • Specification · target
  • Ticket · the way there
  • Code · actual
  1. Interview

    It starts with a conversation: together with the specifier agent I sharpen what should be built and how we will know it is done.

  2. Specification

    The specifier turns that into the specification — the target state as testable criteria — and into tickets for the way there.

  3. Build

    The implementer agent builds ticket by ticket. What it checks off is done — whether it matches the target is decided by inspection.

  4. CI

    The test suite checks every change automatically. Green means: nothing is broken. Not yet: everything is as planned.

  5. Maintenance

    The maintenance agent holds the specification against the code, finds deviations and quality gaps and writes correction tickets.

  6. Correction

    Back to the build. The implementer fixes, CI checks again — fixing continues until everything is green and matches the plan.

  7. Delivery

    Only then does it ship: checked, stamped, rolled out. What gets delivered is what the specification promised.

Stack

Tools, not articles of faith.

Languages & Runtime
node.jsPHPRustHaskellE2E WiederherstellungBashnode.jsPHPRustHaskell
AI & LLM
ClaudeOpenAIlocal LLMs / QwenRAGMCPAgent SDKsEvalsVector DBs
Data & Persistence
PostgreSQLRedisMongoDBSQLiteMySQLMariaDB
Delivery & Architecture
Docker & ComposegRPC / ProtobufClean ArchitectureSOLIDTDDspec-drivenk3s / k8s
Gregor Welters
Person

The Human And The Loop

I'm Gregor Welters, a software developer and architect of more than three decades. I started at ten out of sheer curiosity and never stopped. A digital native before the term existed.

Today I work as a software architect and orchestrator of AI agents: I design the systems, define architecture and quality standards, specify precisely and let models deliver the implementation - spec-driven, test-driven, quality-gated, reproducible, with Clean Architecture and SOLID as guardrails. The result isn't merely faster code, it's code that meets the requirements exactly instead of carrying hallucinated features nobody asked for. And that can still be extended and changed in six months or in years.

Agentic development shifts the work: implementation becomes cheap, design and judgement become expensive. Someone who knows how systems decay over years specifies differently and gets code from the agent that holds, rather than code that merely works.

Architecture AI engineering Spec-driven Team enablement
Places & projects
  • billiger mietwagen
  • brainbits
  • cpa
  • industriewert
  • maklerkanzlei
  • pferdewetten.de
  • silversurfer7
  • uni duisburg essen
  • wewo

Contact

Reachable directly

Tell me what it's about — one line is enough. I reply within one working day, including questions about technology, projects or availability.

gregor.welters@gmail.com +49 163 190 44 60
Available immediately · remote, hybrid preferred · on-site Düsseldorf, Cologne, Wuppertal (Essen as an outer option), up to one hour of travel · Solingen, Germany
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