WHO I AM

Tobias Lettenmeier

Freelance Developer

I don't throw conceptual studies at you, but build you real, running software.

Background: Trained Carpenter

Education: High school (second-chance BOS Ansbach) & B.Sc. in Technomathematics / Mechanical Engineering (FAU Erlangen)

Research: Former Research Assistant at the Chair of Pattern Recognition

Corporate: Software Developer at IBM and the Bavarian Ministry of the Interior

Independence: Freelance Software Developer for agencies and start-ups.

Book a Consultation →

Scope of Work

My Areas
of Expertise.

API & Backend Development

Creation and integration of REST APIs, data pipelines, and microservices using Python. Reliable logic behind your business systems.

Workflow Automation

Automation of time-consuming internal processes and data flows between third-party systems using n8n and LLM APIs (OpenAI, Anthropic).

Serverless Cloud Deployment

Setup and management of cost-efficient, automated hosting environments on Google Cloud (Cloud Run) with CI/CD via GitHub.

Prototype Development

Fast technical implementation of functional web applications (backend + pragmatical frontend). Your MVP up and running in record time.

Emergency Fixes

Something isn't working in code or on the server and needs immediate attention? I quickly analyze and resolve bugs in live environments.

Technical Stack

Focus & Expertise

Daily Practice

Backend: Python (Flask)

Automation: n8n

AI: LLM APIs (OpenAI, Anthropic)

Frontend: HTML / JavaScript

Cloud: GCP (Cloud Run, Serverless)

Databases & Cloud

PostgreSQL / MySQL

SQLite / Redis

Google Cloud Storage

AWS Basic Infrastructure

Self-Hosting: Local Self-Hosting of Open-Source LLMs & Vector Databases (Pinecone, Qdrant)

Frameworks & Libraries

Version Control: GitHub

Computer Vision: YOLO

Deep Learning: PyTorch

PDF/Doc Parsing: Docling

Media Processing: ffmpeg

Math/AI: scikit-learn, DeepXDE

Successful API Integrations

Stripe, YouTube, WhatsApp, Telegram, Calendly, Apaleo, Apify, VertexAI, OpenAI, Anthropic, Elevenlabs, Marketstack, LinkedIn, Instagram, everything in the Google universe and more.

Legal & Data Privacy (GDPR)

EU Hosting & Data Agreements (AVV)

Data processing agreements (AVV) are signed and present for all infrastructure providers. All deployments default to GDPR-compliant servers located within the European Union (EU).

Cloud & Hosting Experience

Provider	Rating	AVV
Railway	excellent	present
Google Cloud (GCP)	good	present
Hetzner (own server)	good	-
AWS	medium	-
Vercel	medium	-

PROJECT OUTLINE

Successful
Reference Projects

MOBILE & WEB

SpeedOff

The lightning-fast quoting tool that saves craftsmen hours of tedious office work after hours. Works offline in the basement or on-site.

Challenge: Paper chaos on the construction site, unclear notes, and hours of manual typing of quotes in the office delay processes and cost craftsmen valuable free time after hours.

Solution: A cross-platform offline-first application. SpeedOff allows craftsmen to create a perfectly calculated quote directly at the customer's site on a tablet or smartphone in under 5 minutes.

Result: Customers receive quotes immediately by email as a fully automated PDF. The administrative effort after hours was reduced by over 80% for participating businesses.

HTML5

JavaScript

Google Cloud

Firebase

Railway

Redis

Python

Learn more about SpeedOff →

WEB INTEGRATION

FuBoMat

An interactive floor visualizer for craftsmen and retailers. Easily embeddable into any website as a lightweight widget.

Challenge: Customers struggle to visualize floor samples in their own rooms. Retailers and flooring businesses face high sample return rates and long consulting cycles due to customer uncertainty.

Solution: A high-performance web application utilizing modern rendering technologies. FuBoMat enables end-users to visualize various flooring designs (hardwood, laminate, vinyl, tiles) in photorealistic room scenes directly on the business's website.

Result: Increased conversion rates, reduced consultation times, and significantly fewer physical sample requests. FuBoMat is built as a universal widget and can be embedded in under 5 minutes into any existing website (WordPress, Webflow, Custom HTML). Try it in the live demo.

HTML5

JavaScript

Python

Google Cloud

Railway

Redis

View Live Demo →

WEB APP

HeyBoss

Employee survey tool for start-ups and businesses.

Challenge: Employee surveys are usually still conducted analogously. The reason is simple: employees can never be absolutely sure that their criticism really stays confidential when the survey is done via email or link, because they can never be certain that the link isn't tied to their device or account.

Solution: With HeyBoss, the link comes from an external company and the evaluation follows the so-called ballot box principle. This means the survey result is 'dropped in' without storing the sender of the response.

Result: Employees receive a link or QR code weekly or monthly and can answer the survey anonymously. The employer receives the survey results presented in a dashboard and can track desired metrics over time like a stock chart.

HTML5

JavaScript

Firebase

Stripe

Python

IOS APP

Lager-Scanner

A native iOS app that records inventory via camera scan and synchronizes the data error-free in real-time with the business's ERP system.

Challenge: Manual inventory taking with clipboards and pens is extremely error-prone, takes days, and leads to discrepancies in the ERP system.

Solution: A native, extremely high-performance iOS app that uses the camera and Apple Vision API to read barcodes in milliseconds. The app immediately reconciles inventory with the database.

Result: Error-free inventory recording in real-time. The time required for the annual inventory was shortened from 3 days to a few hours.

Swift

Vision API

Python

Google Cloud

AUTOMATION

KI-Support-Agent

An intelligent email agent that reads, categorizes, and automatically drafts precise response emails to customer requests based on the company knowledge base.

Challenge: Customer support spends hours answering the same standard questions by email. Complex inquiries get lost in the crowd.

Solution: An intelligent mail agent that semantically analyzes customer inquiries based on LangChain and OpenAI GPT-4, searches the company knowledge base for answers, and automatically drafts precise responses in the inbox.

Result: Support agents only need to briefly check and send replies. Standard response times dropped from 8 hours to under 5 minutes, drastically increasing customer satisfaction.

Python

OpenAI

LangChain

n8n

Qdrant

Ollama

MACOS APP

playSom

A native, resource-friendly macOS menu bar app for streaming SomaFM radio. Seamlessly integrated into the system and fully controllable via media keys.

Challenge: Many radio streaming solutions for macOS are bloated, resource-heavy, or hidden deep inside browser tabs. What was missing was a slim, native app that stays subtly in the background, is quickly accessible, and consumes almost no memory.

Solution: A native macOS menu bar app written in pure Swift 6.0 and SwiftUI. playSom integrates seamlessly into the system, streams 30+ SomaFM channels, supports keyboard media keys, and consumes under 5 MB RAM at idle.

Result: A lightning-fast, minimalist open-source solution for music lovers that integrates inconspicuously into the macOS menu bar, supports native media widgets, and can be controlled directly via keyboard.

Swift

SwiftUI

AppKit

View code on GitHub →

BROWSER APP

Samplify

A simple web app to download audio tracks from videos. Includes MPC-style audio editing.

Challenge: Time is money, even in the music business. Hip-hop production frequently relies on sampling—taking short snippets of audio from existing songs. Extracting these and importing them into a DAW conventionally is cumbersome and time-consuming.

Solution: A browser-accessible tool matching the workflow and style of an analog MPC. Simply paste the link to the song, highlight the desired segments of the audio track, play them live via external MIDI controllers (such as the Novation Launchpad X), and export them as WAV. Every progress step is auto-saved in the browser. It doesn't get any easier.

Result: Sample extraction in seconds. No more tedious clicking back and forth. Highly automated and scalable to thousands of songs.

HTML5

JavaScript

Python

WORKSHOP // TRAINING

n8n AI-Workshop

Hands-on n8n training for employees. Participants learned how to build their own AI agents and automation workflows without any programming knowledge.

Challenge: Many companies want to leverage AI potential, but employees often face programming barriers. Manual workflows in daily business remain time-consuming due to a lack of automation know-how.

Solution: A tailored, interactive in-house workshop. Employees learned the fundamentals of n8n and built step-by-step their own AI agents to process customer data, reply to emails, and automate routine tasks.

Result: Over 15 independently developed AI agents in the company. Participating departments immediately automated manual data-entry workflows and gained a deep understanding of practical AI use cases.

n8n

OpenAI

Anthropic

AI AUTOMATION

KI-Video-Creator

A fully automated AI agent that generates complete videos (story, voiceover, image & sound) for children via WhatsApp and uploads them to YouTube.

Challenge: Whether we like it or not: More and more children are growing up with smartphones, and video consumption will continue to rise. Why not use technology to create meaningful videos? That is exactly what I implemented for a YouTube channel in this project.

Solution: A fully automated workflow powered by n8n. The channel operator can request a video via WhatsApp or a dedicated web interface (e.g. 'Create a video about being strong in life'). The pipeline autonomously generates the story, matching images, animations, voiceover, and compiles everything into a finished 60-second video.

Result: After a quick manual approval by the operator, the system uploads the video fully automatically via the YouTube API. The result is 60-second videos. Here is an example video.

n8n

OpenAI

Python

YouTube API

Watch Example Video →

FAQ

Frequently Asked Questions

How does the collaboration work? +

1. Getting to know each other: We start with a brief, free call to outline your requirements and goals.

2. Proposal: After that, I will provide you with a concrete proposal. This can be either on an hourly rate basis for ongoing support or as a fixed price for a clearly defined work package (e.g., a prototype).

3. Development & Feedback: During development, you will receive regular updates (e.g., access to a staging environment) so we can quickly incorporate your feedback.

What is your hourly rate? +

It is my personal experience—and studies back this up—that billing purely by time often works against the project's success (providing little incentive for efficiency).

That's why I prefer working on a performance/value basis (e.g., a fixed price for a clearly defined work package). This encourages both of us to clearly define the desired outcome upfront and ensures maximum efficiency.

If hourly billing is unavoidable, my rate ranges between 50 € and 100 €, depending on the duration, urgency, and complexity of the project.

CONTACT

LET'S WORK TOGETHER.

Do you have a specific project, a bottleneck in your team, or need a fast prototype? Book a short, hassle-free conversation.

Book a Call Now → Or write me an email →

🍪 Cookie-Einstellungen

Tobias Lettenmeier

Freelance Developer

My Areasof Expertise.

API & Backend Development

Workflow Automation

Serverless Cloud Deployment

Prototype Development

Emergency Fixes

Focus & Expertise

Daily Practice

Databases & Cloud

Frameworks & Libraries

EU Hosting & Data Agreements (AVV)

Cloud & Hosting Experience

SuccessfulReference Projects

SpeedOff

FuBoMat

HeyBoss

Lager-Scanner

KI-Support-Agent

playSom

Samplify

n8n AI-Workshop

KI-Video-Creator

Frequently Asked Questions

LET'S WORK TOGETHER.

Free Consultation

SUCCESS! WE GOT YOU.

My Areas
of Expertise.

Successful
Reference Projects