Available for new projects

Custom software, built by a 35-year veteran.

From mainframes to microcontrollers, I design and build reliable, beautiful software for businesses, educators, and innovators. One developer, full-stack — no agency markup, no surprises.

All Software Developed source code distributed with the final product, to clients.

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Total of 268+ clients trust DevDannyD with their critical systems
A senior developer working at a modern desk with multiple monitors showing code and circuit schematics
35+
Years Experience
1545+
Applications Built
23+
Technologies Mastered
Five eras of computing
COBOL Pascal, Delphi, Visual Basic Basic, MSBasic, QBasic, TBBasic 8086 Assembler C, C++, C# Clarion Developer PHP, HTML, CSS MySQL Python Arduino Raspberry Pi iOS Android Linux Windows
My Journey

Three decades of shipping software

From green-screen mainframes to modern IoT — here's how the experience stacks up.

A vintage mainframe room with green-screen terminals and reel-to-reel tape drives, soft amber lighting
1989 - 2000

The Mainframe Era

Cut my teeth on enterprise mainframe systems — COBOL, Natural, and Adabas — building mission-critical financial and administrative software that processed millions of transactions a day. This era taught me what reliability really means.

COBOL Natural Adabas Mainframe
A late-90s beige PC tower next to a CRT monitor showing Visual Basic IDE and assembly code
2000 - 2008

The Windows Revolution

Moved to PC-based development as the industry shifted. Mastered C++, Assembly, and Visual Basic, building high-performance desktop apps and Win32 services. Low-level memory management and OS internals became second nature.

C++ Assembly Visual Basic Win32 Pascal
A first-generation iPhone, an early Android phone, and a laptop running PHP code in a browser
2008 - 2015

Web & Mobile Emergence

Embraced the web with deep PHP, SQL, and C# work — full-stack platforms, e-commerce, CMSes, and analytics dashboards. Expanded into iOS and Android native apps, pioneering responsive design before it had a name.

PHP SQL C# iOS Android MySQL
A Raspberry Pi connected to sensors with colourful jumper wires next to a tablet running an accessible learning app
2015 - 2023

Hardware Integration & Accessibility

Discovered a passion for merging software with physical computing — Raspberry Pi, Arduino, sensor networks, IoT. Pivoted toward accessibility-focused software for children with special needs: educational tools, therapeutic apps, adaptive interfaces. Linux became home base.

Raspberry Pi Arduino Linux IoT Python Special Needs
A modern multi-monitor workstation showing a cloud dashboard linked to live IoT sensor readings
2023 - Present

Full-Stack Integration & Custom Solutions

Today I architect end-to-end solutions that span embedded devices to cloud platforms. The sweet spot is hardware-to-software integration — sensors and microcontrollers feeding sophisticated web backends — together with bespoke business apps and accessibility tools.

Full-Stack Hardware Integration Custom Solutions IoT Circuit Design Accessibility
What I Do

Comprehensive technical expertise

Six disciplines I've spent decades sharpening — ready to bring to your next project.

Software Development

Full-stack development across multiple paradigms - from low-level systems programming to modern web apps.

PHP C++ C# Python Visual Basic COBOL Pascal Assembly

Database & Backend

Enterprise database architecture, query optimization, and reliable backend systems built to scale.

MySQL SQL Server Adabas Natural REST APIs Backend Services

Mobile Development

Native and cross-platform mobile apps that integrate seamlessly with your web backend.

iOS Android Swift Cross-Platform UX Integration

Hardware & Embedded

Circuit design, embedded firmware, sensor networks - bridging the physical and digital worlds.

Raspberry Pi Arduino Circuit Design Sensor Integration IoT Real-time OS

Operating Systems

Mainframe to embedded Linux - system-level programming, optimization, and admin.

Linux Windows Mainframe OS Embedded Linux SysAdmin

Accessibility & Special Needs

Custom software for children with special needs - adaptive, engaging, therapeutic, inclusive.

Adaptive UIs Educational Tools Therapeutic Apps Inclusive Design
Selected Work

Projects that made a difference

A small selection of shipped applications across education, healthcare, IoT, AI and enterprise.

AI AI Prompt Maker

AI Prompt Maker

Generate detailed prompts for AI-generated images, videos, music, lyrics, coding and Education using curated selections — designed to inspire your creative projects. Generate Lyrics, Songs, Voiceovers, Prompt to Image, Image to Video

PHP MySQL JavaScript Grok AI API
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FREE - Tools

FREE Travel GPS

Record any journey on Baidu Maps or OpenStreetMap with one tap. Drop Start, End, and photo-tagged Points of Interest as you go, and save a Home address you can route back to with a single click. Long-press anywhere on the map for instant directions, voice navigation, or to save a spot. Browse every POI in one searchable, filterable list. Share any trip publicly with a no-login link, or let other registered users import it into their own account.

API GPS Maps PHP Javascript
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Education

EduKids Learning

EduKids Learning provides interactive education through engaging games and online storybooks. We offer custom development services for educational games and tailor content for students with disabilities, ensuring every child can unlock their full potential and develop a lifelong love of learning.

PHP Javascript. MySql CSS CSM
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Financial

Biz Ledger

BizLedger is a lightweight, no-fuss accounting system built for small businesses that need professional financial control without the enterprise price tag. Manage your invoices, purchase orders, debtors, creditors, stock, and general ledger all in one place — with real-time dashboards that give you an instant snapshot of your cash position.

Financial PHP Javascript PHP Data Encryption 100% secure
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AI

AI Storybook Creator

Fun AI tool that turns simple ideas into beautifully illustrated children’s storybooks plus short animated videos with voice-over. Key elements: "Turn Any Idea Into a Magical Storybook" + "Beautiful illustrated children’s stories + ready-to-watch animated videos."

AI API PHP Javascript GROK xAI
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Software

Leznad Software

Full-stack custom software development (Windows, iOS, Android, Linux) with a strong specialization in inclusive educational technology — particularly tools for students with disabilities (autism, dyslexia, speech-to-text interfaces, visual schedules, gamified learning, simplified UIs, adaptive testing, accessibility plugins, and Learning Management Systems). Offer websites/web apps, Chrome extensions, and even 3D-printed assistive devices.

Website Software PHP MySql CSS HTML Education
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Education Children using a colourful tablet-based learning app with adaptive interface

Special Needs Learning Platform

Custom educational software for children with autism and developmental differences - adaptive interfaces, multi-sensory feedback, and progress tracking for therapists and parents.

PHP MySQL JavaScript
IoT / Hardware Smart-home dashboard showing temperature, lights and security across rooms

Smart Home Automation

Arduino-based whole-home automation with a unified web dashboard. Remote monitoring and control for lighting, climate, and security - rock-solid even on flaky home Wi-Fi.

Arduino PHP IoT
Enterprise Abstract visualisation of legacy mainframe data flowing into a modern SQL database

Financial Data Migration Suite

Mission-critical conversion of legacy COBOL/Adabas data to modern SQL Server - zero data loss, full audit trail, and a 4x speed improvement on the new platform.

COBOL C++ SQL
E-Commerce A clean modern e-commerce checkout screen on laptop and phone

Scalable Shopping Platform

Full-stack e-commerce with inventory, payments, and live order tracking. Now serving a mid-size retailer that scaled 10x on the same codebase without breaking a sweat.

PHP MySQL Payment APIs
Mobile An iPhone showing a clean health tracking app with charts

iOS Health Tracker

Native iOS app for patient health metrics, with HIPAA-friendly cloud sync and a clinician-facing portal. Used by thousands of patients in their daily care routine.

iOS Swift Backend API
Embedded A weatherproof environmental sensor box outdoors with antenna and solar panel

Environmental Monitoring Network

Raspberry Pi-based outdoor sensor network for air quality, temperature, and humidity. Live web visualisation and configurable alerting - deployed across multiple sites.

Raspberry Pi Python Linux
How I Help

Services that cover the whole stack

Concept to deployment, hardware to cloud. One developer, accountable end-to-end.

A laptop showing clean modern code on a dark editor

Custom Software Development

Tailored applications that solve your specific business problem - designed, built, tested, and deployed by one person who owns the whole result.

An Arduino board with sensors connected to a laptop running custom software

Hardware-Software Integration

Bridge the gap between physical devices and digital systems - sensors, microcontrollers, and embedded boards talking to powerful web backends.

An old mainframe terminal next to a modern web dashboard, illustrating modernisation

Legacy System Modernization

Migrate outdated mainframe and legacy systems to modern platforms while preserving every record, every workflow, and every line of business logic that matters.

A child smiling while using an accessible learning app on a tablet

Accessibility & Special Needs

Inclusive software for children and learners with special needs - adaptive interfaces, therapeutic engagement, and respectful, evidence-informed design.

A custom PCB schematic and a soldered prototype board on a desk

Circuit Design & Prototyping

Electronic circuit design, PCB layout, and Arduino / Raspberry Pi prototyping for IoT and embedded applications - from breadboard to production.

Two engineers reviewing architecture diagrams on a whiteboard

Technical Consulting

Strategic technology guidance, architecture planning, and a frank second opinion on platform choices, build-vs-buy, and risk - backed by 30 years of scars.

Kind Words

What clients say

Selected feedback from people I've shipped software with.

★★★★★

"Danny's special needs software transformed how our students engage with learning. The adaptive interfaces and multi-sensory design are incredible. His understanding of accessibility is unmatched."

Portrait of Maria S., Educational Technology Director
Maria S.

Educational Technology Director

★★★★★

"From hardware design to full-stack implementation, Danny delivered our entire IoT solution. His ability to bridge embedded systems and web platforms saved us months of development."

Portrait of John M., IoT Startup Founder
John M.

IoT Startup Founder

★★★★★

"The mainframe-to-modern migration was flawless. Zero data loss, smooth transition, and the new system runs faster. Incredibly professional work with deep technical expertise."

Portrait of Robert C., Legacy Systems Manager
Robert C.

Legacy Systems Manager

★★★★★

"Our shopping platform scaled perfectly. Danny's attention to performance and security is exceptional. We've grown 10× and the system handles it effortlessly."

Portrait of Sarah L., E-Commerce CEO
Sarah L.

E-Commerce CEO

★★★★★

"The iOS health app Danny built is now used by thousands of patients. The synchronization is seamless, and the interface is intuitive. True craftsmanship."

Portrait of Tom C., Healthcare CTO
Tom C.

Healthcare CTO

★★★★★

"Danny's monitoring network has revolutionized our air quality tracking. The Raspberry Pi-based solution is cost-effective, reliable, and provides real-time insights we never had before."

Portrait of Patricia K., Environmental Agency Director
Patricia K.

Environmental Agency Director

Ready to build something exceptional?

Tell me about your idea and I'll tell you, honestly, how to make it real — no sales fluff, just straight talk and a clear next step.

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