What is a Transformer (AI architecture)?

A Transformer is a computer model that reads all words in a sentence at once and figures out which ones matter most to each other. It helps AI write or understand text much faster than older methods.

7 min read min de lecture

~$ man transformer

What is a Transformer (AI architecture)?

Machine & Deep Learning gneurone encyclopedia
A Transformer is a computer model that reads all words in a sentence at once and figures out which ones matter most to each other. It helps AI write or understand text much faster than older methods.

definition

A Transformer is a neural network design introduced in 2017 that processes entire sequences of data using self-attention instead of step-by-step recurrence.

It consists of stacked encoder and decoder layers, each containing multi-head attention and feed-forward networks with residual connections and normalization.

The architecture enables efficient parallel training and captures long-range dependencies in text, images, and other sequential inputs.

Imagine a classroom where every student can instantly read every other student's notes on a shared page instead of waiting for one person to pass information down a line; the class finishes the assignment much quicker and spots connections across the whole page.

key takeaways

  • Self-attention lets each token directly compare itself to every other token in one step.
  • Multi-head attention runs several attention calculations in parallel to capture different relationship types.
  • Positional encodings add order information because the model has no built-in sense of sequence.
  • Transformers scale well to billions of parameters, enabling large language models.
  • The same core blocks are now used for text, images, audio, and protein sequences.

the 2026 job market

By 2026 most production NLP, search, and code-generation systems rely on Transformer variants, so employers seek engineers who can fine-tune, compress, and serve these models at scale in roles such as ML platform engineer and applied research scientist.

Machine Learning Engineer · $135000-195000 USD / $125000-175000 CAD / £95000-145000 GBPNLP Research Scientist · $150000-220000 USD / $140000-195000 CAD / £105000-160000 GBPAI Infrastructure Engineer · $140000-200000 USD / $130000-180000 CAD / £100000-150000 GBP

frequently asked questions

How does self-attention differ from recurrent layers?

Self-attention computes relationships between all tokens simultaneously without sequential steps. Recurrent layers process tokens one after another and struggle with long distances. This parallel design speeds up both training and inference.

What tasks can Transformers handle besides language?

The same architecture works on images in vision transformers, audio waveforms, protein folding, and time-series data. Only the input embedding and output head change for each domain.

Why do Transformers need positional encodings?

Attention itself has no notion of order, so sine or learned positional vectors are added to token embeddings. These vectors let the model distinguish word positions and preserve sequence structure.

How many parameters do typical production Transformers contain?

Base models start around 100 million parameters while large deployed systems range from 1 billion to over 100 billion. Size depends on task accuracy needs and available compute budget.

courses to go further

$ cat ./full-guide.mdTransformers Deep Learning en pratique : le code et les commandes qui comptent vraimentread the guide →

related terms

< back to the encyclopedia

Auteur(s)

R

REHOUMA Haythem

Haythem Rehouma est un ingénieur et architecte IA et cloud, formateur et enseignant technique, avec un profil orienté IA médicale, AWS, MLOps, LLM/RAG et vision par ordinateur.