Real-Time Guitar Chord & Note Recognition — On-Device Audio ML (Proof of Concept to Start)

I'm the founder of FretFlow, a guitar-learning app for beginners — a flowing, color-coded fretboard that shows you how to play the songs you love and slows down when you fall behind. The app is built and running on iPhone. I'm now building the feature at the heart of it, and I need a specialist for the one piece I can't build myself. THE WORK Build FretFlow's real-time audio recognition engine: it hears a guitar through the phone's microphone and identifies the chords and notes being played, live, on the device. I want to start with a small, paid PROOF OF CONCEPT — a working demo that recognizes guitar chords (and ideally individual notes) in real time from mic input. If it works and we work well together, it grows into the full engine and a longer contract. WHAT THE PROOF OF CONCEPT SHOULD SHOW - Live chord recognition from a guitar through a microphone, in real time - A clear path to running on-device on a phone (Core ML / TensorFlow Lite), low latency — not server-dependent YOU'RE A FIT IF YOU'VE: - Built audio/music ML focused on RECOGNITION — chord detection, pitch/note detection, music information retrieval (NOT music generation) - Run audio ML models ON a mobile device (Core ML, TensorFlow Lite, or ONNX) - Worked with real-time, low-latency audio NICE TO HAVE: React Native / Expo familiarity; tools like Essentia, librosa, CREPE, or basic-pitch; you play guitar. ABOUT THE STAGE Early-stage, founder-led, pre-launch. This is a paid contract starting with the proof-of-concept, with real room to continue. I'm looking for someone excited to build the brain of a product from the ground up. Please answer the screening questions below — proposals that show specific chord/pitch-recognition and on-device work go to the top of my list. 1. Have you built a chord or note/pitch recognition system before? Briefly describe it and share a link if you can. 2. Have you run an audio ML model on a mobile device (Core ML, TensorFlow Lite, or ONNX)? Which one, and roughly what latency did you get? 3. In a sentence or two, how would you approach real-time chord recognition from a phone's microphone?