Comprehensive developer-focused chronicle of LLM evolution from foundational research to production APIs
54 Major Milestones • 2015-2025 • Detailed Technical Specifications
Bahdanau et al. introduce attention mechanism for neural machine translation
Vaswani et al. introduce the transformer architecture
Universal Language Model Fine-tuning introduces transfer learning to NLP
Embeddings from Language Models - first major contextual word embeddings
First GPT model - proves generative pre-training works
Bidirectional Encoder Representations from Transformers
Smallest GPT-2 variant released
Full GPT-2 released after staged rollout due to safety concerns
Transfer Text-to-Text Transformer - unified framework
Largest language model, API-only access, few-shot learning breakthrough
More affordable GPT-3 variant for simpler tasks
GPT-3 fine-tuned on code, powers GitHub Copilot
First instruction-tuned GPT-3 model using RLHF
Production instruction-tuned model with extended context
Improved instruction following and reduced harmful content
Chat-optimized model, 100M users in 2 months
High-performance open research model
First major multimodal LLM with vision capabilities
Extended context variant of GPT-4
Extended context for GPT-3.5 at accessible pricing
First production model with 100K context window
First major open-source model with commercial license
GPT-3.5 in completions format for backwards compatibility
Massive context increase and cost reduction
Updated GPT-3.5 with better accuracy and 50% cost reduction
Google's first production LLM API
Fastest Claude model with instant responses
Mid-tier Claude with excellent balance
Matches or exceeds GPT-4 on many benchmarks
Updated GPT-4 Turbo with improved performance
Native audio, vision, and text in single model
Unprecedented context window breakthrough
Fast, affordable model with 1M context
Best coding model, beats GPT-4o on many benchmarks
Most cost-efficient small model
Largest open source model, rivals closed-source leaders
Chain-of-thought reasoning for complex problems
Faster, cheaper reasoning model for STEM
Adds computer use capabilities - can control desktop
First model with native image and audio generation
Exceptional coding and math at breakthrough low pricing
Introduces Deep Think mode for complex reasoning
Major architectural improvements and reasoning advances
Third generation with multilingual excellence
World record 2M token context with fast inference
Improved mixture-of-experts for better efficiency
Dynamically adjusts thinking time based on complexity
First model to break 1500 LMArena Elo barrier
Tops real-world GitHub issue resolution at 77.2%
Optimized for long-running agents and complex workflows
Fastest Claude 4.5 with excellent value
Released during intense 6-day November competition
Released after internal "code red" to reclaim leadership
Frontier intelligence built for speed at exceptional value
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