GPT

GPT-6.1 Sol (September 29, 2026) is OpenAIs low-cost coding and agentic model — the successor to GPT-6 Sol after just seven days, with near GPT-6 Astra intelligence at roughly a fifth of the price. Available via boostN.

GPT-6 Astra is OpenAIs flagship from September 2026 — the first model at the Critical Preparedness tier, focused on computer use and cybersecurity.

GPT Luna (GPT-5.6 Luna) is the smallest, fastest and most affordable model of OpenAIs GPT-5.6 family, released in July 2026. It is built for cost-sensitive, high-volume workloads and offers a context window of roughly 1.05 million tokens.

GPT-5.6 Sol is OpenAIs flagship from July 2026 — the top model of a new solar-system family (Sol, Terra, Luna) focused on coding, science and cybersecurity.

GPT Terra is the middle tier of OpenAIs GPT-5.6 family (July 2026), sitting between the efficient Luna and the flagship Sol — built for a strong price-performance balance with a 1M-token context.

OpenAI's real-time voice model, the default voice experience in ChatGPT since 8 July 2026. It listens and speaks at the same time (bidirectional), allows interruptions, and hands complex questions off to a stronger text model. Proprietary access via ChatGPT.

GPT-4o (May 2024) was OpenAI's first natively multimodal model — text, audio and image in a single model, with a real-time voice mode and substantially lower cost than GPT-4 Turbo.

GPT-4o mini (July 2024) is OpenAI's small, low-cost variant of GPT-4o — positioned as the successor to GPT-3.5 Turbo, clearly stronger at a much lower price per token.

GPT-5.2 is OpenAI's model generation from December 2025 — three variants (instant, thinking, Pro), a 400k context window and new state-of-the-art on professional knowledge work.

GPT-5.3 is an iteration of OpenAI's GPT-5 line — the Instant variant launched on March 3, 2026 with a focus on factual accuracy, shorter preambles and a more natural conversational flow.

GPT-5.3-Codex is OpenAI's specialized agentic coding model (February 2026), the successor to GPT-5.2-Codex — 25% faster, with substantial gains on Terminal-Bench and OSWorld.

GPT-5.3-Codex-Spark is OpenAI's coding model from February 2026 — a smaller, real-time-optimized variant of GPT-5.3-Codex delivering over 1000 tokens per second on Cerebras hardware.

GPT-5.4 is OpenAI's reasoning model from March 5, 2026 — the first mainline model with the coding capabilities of GPT-5.3-codex, native computer-use controls and 1M-token context.

GPT-5.5 is OpenAI's flagship from April 23, 2026 — positioned as its "smartest and most intuitive model" and pitched as a step toward AI that works across tools on its own.