Lexi: write well by talking

GPT-4 is a large language model developed by OpenAI and released in March 2023 as part of the Generative Pre-trained Transformer series. It accepts text input and produces text output, with a context window of 8,192 tokens, and its training data has a knowledge cutoff of April 2023. GPT-4 was designed to improve on earlier GPT models in areas such as instruction following, contextual understanding, and factual accuracy across a wide range of topics.

Whisper is a general-purpose speech recognition model developed by OpenAI and made available via the OpenAI API under the model ID whisper-1. It was trained on a large dataset of diverse audio, enabling it to handle a wide range of accents, background noise conditions, and technical vocabulary. What distinguishes Whisper is its multitask design: it can perform not only speech-to-text transcription but also speech translation into English and automatic language identification within a single model.

GPT-5.4 is a text generation model developed by OpenAI, released in March 2026 as their flagship model for professional and enterprise use. It is available in three variants — standard, Thinking, and Pro — and features a context window of 1 million tokens, the largest OpenAI has offered. The model is designed not only to plan complex tasks but to complete them reliably, with built-in computer use capabilities for orchestrating multi-step agentic workflows.

GPT-5.4 Pro is a text generation model developed by OpenAI, released in March 2026 as part of the GPT-5.4 family. It is one of three variants in that family — alongside the standard GPT-5.4 and GPT-5.4 Thinking — and is specifically optimized for deep analytical work through multi-path reasoning evaluation. The model supports a context window of 1 million tokens, the largest OpenAI has offered, enabling it to process extensive documents, codebases, and multi-step workflows within a single session.

Compare GPT 5.4 and GPT 5.4 Pro across pricing, context window, capabilities, benchmarks, and API access to choose the better fit for long-context workloads versus long-context workloads.

Compare GPT 5.5 and GPT 5.4 across pricing, context window, capabilities, benchmarks, and API access to choose the better fit for long-context workloads versus long-context workloads.