d
developerskh

Kai k.

@developerskh
5.0(17)

Level 1

Senior Software Engineer

United Kingdom
English, German, French, Spanish, Arabic
About me
Senior Full Stack Developer | React | Node.Js | Supabase | AI SAAS | AI agents | AI Chatbots Hi! I’m a Sr. Full Stack Developer with 9+ years of experience delivering scalable, MVPs and enterprise-level web applications for clients globally. What I Offer ✅ Custom Web Applications (React, Next.js, Node.js) ✅ Enterprise SaaS Development (multi-tenant, scalable systems) ✅ API Development & Integrations (REST, Webhooks, CRMs) ✅ Admin Dashboards & CMS Solutions ✅ Industry Solutions: Real Estate, Education, Retail & eCommerce, Logistics, Energy, Aviation, Healthcare Let's Start - Order Now... Read more

Skills

d
developerskh
Kai k.
$24/hour
Offline • 
Average response time: 1 hour

See my services

Custom Websites
I will be your full stack developer for react, nextjs, nodejs and nestjs
5.0(9)
Custom Websites
I will develop fast and responsive front end using react, nextjs, vuejs, gsap or 3js
5.0(4)

Want to work on an hourly basis?

Tell Kai k. what you need.

$24

/

hour

Portfolio

Work experience

CEO

Developer Tag • Self-employed

Sep 2025 - Present8 mos

Founder & CEO with a strong engineering background and hands-on development experience, leading a small, high-performing team of developers. I actively contribute to system architecture, core development, and technical decision-making while overseeing delivery and quality. My team is capable of building fast, scalable, and affordable products without compromising on performance, security, or maintainability. We specialise in SaaS platforms, enterprise web applications, AI-driven automations, and custom CRM systems, delivering solutions that align closely with business goals. I combine technical execution with leadership, ensuring projects move quickly from concept to production with clear communication, realistic timelines, and cost-effective delivery.

Lead Software Engineer

Programmers • Full-time

Jul 2023 - Oct 20252 yrs 3 mos

1) Own system architecture for biometric verification workflows (KYC, AML, identity matching) 2) Lead design decisions for high-throughput, low-latency systems 3) Review and approve technical designs, PRs, and deployments 4) Enforce engineering best practices (security, testing, performance) mplement secure-by-design systems for biometric data 5) Ensure compliance with GDPR, ISO 27001, SOC 2, and RegTech standards 6) Oversee data encryption, access controls, and audit logging

Senior Software Engineer

JOIN Solutions Gmbh • Part-time

May 2022 - Apr 20252 yrs 11 mos

Spearheaded the development of features that maximize revenue by 30%. Optimized existing codebase, resulting in a 25% improvement in application performance. Implemented automated testing protocols, reducing bug reports by 40% Architected and led the development of scalable, high-performance web applications using modern JavaScript frameworks (React.js, Next.js) and backend services (Node.js, Express). Oversaw CI/CD pipeline implementation (GitHub Actions, Jenkins) to streamline deployment workflows and reduce release cycles. Collaborated with UI/UX designers to build responsive, accessible interfaces using Tailwind CSS and componentbased architecture. Led microservices-based backend design, utilizing RESTful APIs and optimizing database interactions with MongoDB and PostgreSQL. Spearheaded code quality assurance via automated testing (Jest, Cypress) and enforced TypeScript standards across the codebase.

17 Reviews
5.0

(17)
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Rating Breakdown
  • Seller communication level
    5
  • Quality of delivery
    5
  • Value of delivery
    5
1-5 out of 17 Reviews
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Most relevant
    R
    image-docs

    ryanwalker007

    Repeat Client

    US

    United States

    5

    Very reliable and easy to work with. Understood the requirements clearly and delivered on time. The solution was clean and worked as expected. I would say it's a 10/10 service

    Up to $50

    Price

    10 days

    Duration

    gig

    Custom Websites

    Helpful?
    Yes
    No
    T

    tommy_johnn2

    Repeat Client

    GB

    United Kingdom

    5

    Mikael handled the project efficiently and communicated clearly. Everything was delivered on time and worked as expected. He is BEST one I ever meet on Fiverr

    $50-$100

    Price

    5 days

    Duration

    gig

    Custom Websites

    Helpful?
    Yes
    No
    B

    brown1865

    US

    United States

    5

    Good attention to detail. Identified the validation bug and fixed it properly instead of applying a quick patch. Reliable developer with solid backend knowledge.

    Up to $50

    Price

    4 days

    Duration

    gig

    Custom Websites

    Helpful?
    Yes
    No
    A

    alex_morganz

    Repeat Client

    US

    United States

    5

    Quick, efficient, and very reliable. Good experience overall.

    Up to $50

    Price

    5 days

    Duration

    gig

    Custom Websites

    Helpful?
    Yes
    No
    T

    tommy_johnn2

    Repeat Client

    GB

    United Kingdom

    5

    Very solid developer. Took ownership and handled everything properly. 10/10 Recommended

    Up to $50

    Price

    2 days

    Duration

    gig

    Custom Websites

    Helpful?
    Yes
    No