Weekend Project: Training a GPT-2-Level Model from Scratch

X post0xSeroResource

In a post on X, 0xSero outlines a weekend project aimed at training a GPT-2-level language model using Python. According to the author, the setup requires around 4 to 8 hours and roughly $50 in compute costs, leveraging Andrej Karpathy's educational resources.

Key points

  1. Key topics covered include datasets, Chinchilla scaling laws, compute provisioning, training runs, Supervised Fine-Tuning (SFT), and benchmarks.
  2. Estimated commitment is 4 to 8 hours with compute costs of approximately $50.
  3. The post recommends Andrej Karpathy's YouTube tutorials alongside the nanoGPT repository (which notes nanochat as its newer successor).
  4. In the thread, 0xSero announced an upcoming bounty for adapting nanochat to reinforcement learning (RL) and offered to sponsor GPU costs for up to four people.

Why it matters

Many software engineers interact with AI strictly via high-level APIs. Training a medium-sized model from scratch demystifies compute requirements, data tokenisation, and architectural scaling without enterprise-level infrastructure.

Analysis

Karpathy's nanoGPT repository provides a lightweight codebase to experiment with training loops. While 0xSero cites a 4 to 8 hour timeframe for the project, full training runs can take considerably longer—0xSero's own previous logs reported around 55 hours across four RTX 3090 GPUs. Nonetheless, it represents an accessible starting point for developers looking to understand the fundamentals of training modern transformer models.

Original post

0xSero

@0xSero · 22 August 2026

Weekend project to level you up. Cost: 50$~ Time: 4-8 hours Goal: Train GPT2 level model Language: Python You'll learn: 1. Datasets 2. Chinchilla 3. Provisioning Compute 4. Training 5. SFT 6. Benchmarks Karpathy's YouTube series is excellent alongside t.co/Ts4iGGYR6Z t.co/20UYEnQdT9

1.1k likes19 replies1.2k bookmarks69.1k views

View on X
More posts in the thread (6)
  1. Next week I will put up a bounty for doing nanochat but for RL
  2. I'm open to paying for your gpu hours on this if you don't have the means, I can maybe pay for 4 people. DM or comment
  3. @orionmaximalist you need curiosity and a model to prompt
  4. @sachindetrax my account shows what i'm doing
  5. @vstalingrady how many gpus and for how long
  6. @vstalingrady i'll get back to you
Selected replies (5)
  • @vstalingrady @0xSero Hi Sero, I'm currently training an open source on-device AI slop detector inspired by your image slop detector extension t.co/JesPQmFBvT currently renting gpus and it's eating my wallet. Appreciate any help!
  • @vstalingrady @0xSero one 4070ti super equivalent to finetune liquid 2.5 350m encoder. training will only take 12 hours but trial and error could be 2-3 days
  • @orionmaximalist @0xSero Do we need coding experience for this?
  • @sachindetrax @0xSero Why dont you try to build or tinker new architecture? If i gad a setup like yours then i would have tried tinkering or trying new architectures and benchmarks them
  • @vstalingrady @0xSero Thank you!

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Summary generated by AI (Gemini 3.8 Flash, 27 September 2026). It may contain errors – the original source is authoritative.

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