Videos for developers

Three and a half hours that replace a shelf of blog posts. Karpathy walks the whole training stack, pretraining through post training, and explains why models hallucinate, why they are bad at counting letters, and what a token really is. If you build on top of models, this is the clearest explanation of what is underneath.

Short videos where university researchers explain computer science topics properly, from hashing and compression to cryptography and floating point. Casual viewing that quietly fills in real gaps.

A long running podcast answering listener questions about the non technical side of engineering: bad managers, awkward teammates, promotions, quitting and negotiating. The closest thing to a free mentor answering the questions you cannot ask at work.

Conference talks and writing on engineering leadership, covering team health, technical strategy, incident culture and the practical mechanics of leading engineers. A large free archive of talks from people doing the job.

Thirty small projects in thirty days, built in plain JavaScript with no frameworks, libraries or build tools. The fastest cure for framework dependence.

Algorithm explanations that spend the time on why a solution is correct rather than racing to the code, which is the part most walkthroughs skip. Free, and unusually good at the hard topics.

Builds neural networks and then a working language model from scratch in Python, one line at a time, with nothing hidden behind a framework. The clearest available answer to the question of what a model is actually doing.

Visual explanations of what a neural network is, how gradient descent works and what backpropagation is doing, plus later episodes on transformers and attention. The mathematics stops being intimidating when you can see it move.

Deep, unhurried explanations of the layers most engineers treat as opaque: TCP and HTTP behaviour, connection pooling, database internals, indexing and proxying. Practical knowledge that makes design answers concrete rather than abstract.

One of the first channels to make system design interviews approachable, with whiteboard walkthroughs of scaling problems, sharding, consistent hashing and message queues. A good free starting point before committing money.

A full Cambridge undergraduate distributed systems course, recorded and free, covering logical clocks, broadcast, replication and consensus with actual rigour. Free university material of this quality is rare.