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Callum Macpherson

About

I’m an AI engineer in London. At Runna, I build the ML systems that make millions of people healthier runners. Before that, I spent time at AWS helping customers ship custom AI — from post-trained LLMs and autonomous agents to computer vision pipelines — across robotics, finance, healthtech, aviation, and more. I’ve worked with every modality you can throw at a GPU: video, images, audio, text.

I write about the engineering that gets models from notebook to production: retrieval systems, voice agents, evaluation frameworks, and the deployment details nobody warns you about.

What I write about

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