Milestones timeline
How did we get to today's chatbots?
From 2020 onward, scaling the transformer produced GPT-3, then ChatGPT brought it to the public, GPT-4 added images, and frontier models turned toward coding and agents.
Once the transformer existed, the recipe for a few years was largely to make the models bigger and train them on more text. That scaling is what produced the chatbots most people now use.
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2020 — GPT-3. OpenAI described GPT-3 in a preprint dated 28 May 2020 and opened API access the following month. With 175 billion parameters, it showed that a single large model could handle many language tasks from a prompt alone, without task-specific retraining.[1]
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2022 — ChatGPT. OpenAI released ChatGPT on 30 November 2022. Wrapping a capable model in a simple chat interface brought the technology to a general audience and set off the current wave of interest.[2]
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2023 — GPT-4. OpenAI released GPT-4 on 14 March 2023. Unlike its predecessors it was multimodal, accepting images as well as text as input.[3]
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2025 — Coding and agent models. Frontier releases shifted toward software development and tool use. Anthropic announced Claude Opus 4.5 on 24 November 2025, positioning it for coding, agents, and computer use.[4]
Version numbers in this list will keep changing. What is steadier is the direction: bigger trained models, then a usable interface, then models aimed at acting through tools rather than just answering.
References
- GPT-3 — Wikipedia
- ChatGPT — Wikipedia
- GPT-4 — Wikipedia
- Introducing Claude Opus 4.5 — Anthropic