Building a Transformer LLM from Scratch using Low-Level PyTorch — PickAClass
⏱ 2h 42m 📚 27 lessons

Building a Transformer LLM from Scratch using Low-Level PyTorch

Master the core mechanics of Large Language Models by implementing the full Transformer architecture, including BPE tokenization and self-attention, using pure Python and PyTorch.

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About this course

The complexity of modern Large Language Models (LLMs) can feel like a black box, making it difficult to truly grasp how they function. This course strips away the high-level frameworks to reveal the fundamental mechanisms powering models like GPT. By the end of this course, you will have implemented the entire core Transformer architecture from scratch, gaining a deep, practical understanding of every layer, from raw text input to generated output. This hands-on, low-level approach ensures you gain the architectural knowledge required to debug, optimize, and innovate future models. What you'll learn: * Understand the mathematical foundations of the self-attention mechanism, multi-head attention, and positional encoding. * Implement Byte Pair Encoding (BPE) for efficient text tokenization and vocabulary management from raw data. * Build the full Decoder-only Transformer stack (like GPT) using only low-level PyTorch primitives and modules. * Practice modern Python and PyTorch conventions, including effective device management and robust implementation using static type hinting. * Apply techniques for text generation, including sampling and greedy decoding, to perform inference with your custom model. * Configure basic training loops and understand the crucial gradient flow necessary for optimizing large language models. The course begins with foundational concepts of sequence modeling and attention, then systematically guides you through implementing each component of the Transformer layer-by-layer in Python and PyTorch. You will connect these parts to form a functional, trainable LLM architecture ready for experimentation. This course is designed for beginner and intermediate developers familiar with basic Python syntax who want to transition into deep learning and AI engineering. No prior experience with PyTorch or neural network architectures is required. Start building your foundational knowledge in generative AI today.

What you'll get

  • 📜 Certificate of completion
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  • 💬 Personal AI tutor
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  • ♾️ Lifetime access
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  • 📱 Phone or computer
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  • 💸 14-day refund
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  • Short & focused
    2h 42m of practical content

Certificate of completion

Every course you complete on PickAClass issues a credential like this — original, with its own code, verifiable by URL, and detailed about what was actually demonstrated.

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Certificate of Mastery
This certifies that
Name Surname
has successfully demonstrated mastery of
Building a Transformer LLM from Scratch using Low-Level PyTorch
Skills demonstrated
Behavioral pattern analysis
Foundational
1.2 hrs
Decision-architecture frameworks
Proficient
1.4 hrs
A/B test design
Proficient
1.7 hrs
Behavioral copywriting
Advanced
1.9 hrs
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PickAClass — Name Surname
Building a Transformer LLM from Scratch using Low-Level PyTorch
Page 2 of 2
Performance detail
Coursework summary
Lessons completed 14 / 14
Practice questions 26 / 28
Assignments submitted 4 (avg 4.5 / 5)
Capstone project Reviewed — 4.6 / 5
Total practice 6.2 hrs
Performance benchmark
Cohort rank Top 12% of 1,625
Time to completion 11 days (median: 22)
Mastery score 91 / 100
Practice-question score 94%
Skill verification Verified Skill Path
Verify this credential
pickaclass.com/certificates/PCC-2026-X4F7-AP19
Issued under the academic standards of PickAClass. Skill levels reflect assessed performance against the course's competency rubric. This is an original credential of this platform.

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Frequently asked

What do I need to take this course? +

Just a phone or computer with internet. No installs, no special hardware.

How do I pay? +

By card via Stripe. We don’t store card details — Stripe handles them securely.

Can I get a refund? +

Yes — full refund within 14 days, no questions asked.

How long will I have access? +

Forever. Once you purchase, the course is yours to revisit anytime.

Will I get a certificate? +

Yes. On completion you'll receive a certificate you can add to your LinkedIn profile.

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