GPT (Generative Pre-trained Transformer) by OpenAI
OpenAI’s GPT series has continued to advance rapidly, with new releases now arriving every few weeks. The current flagship is GPT-5.5, released in April 2026.
GPT-5.5 GPT-5.5 is OpenAI’s most capable model, built for long-horizon agentic tasks — multi-step workflows involving research, tool use, and complex execution that previously required human supervision. It excels at writing and debugging code, analysing data, creating documents and spreadsheets, operating software, and moving across tools until a task is finished. It is available in standard, Thinking, and Pro variants for paid subscribers.
GPT-5.5 Instant Released as the default ChatGPT model in May 2026, GPT-5.5 Instant prioritises low latency for general conversational use while reducing hallucination in sensitive areas like law, medicine, and finance.
Llama by Meta
Llama is Meta’s family of open-weight large language models, available for self-hosting and on-premise deployment — a key advantage for organisations with data sovereignty, cost, or customisation requirements.
The current generation, Llama 4, was released in April 2025 and introduced a Mixture-of-Experts architecture with native multimodal training. Two variants are publicly available: Llama 4 Scout (17B active / 109B total parameters) ships with a 10-million-token context window — the largest of any open-weight model — making it suitable for processing entire codebases, document corpora, or multi-year archives in a single context. Llama 4 Maverick (17B active / 400B total) trades context window for raw capability, competing meaningfully with proprietary models on coding and reasoning benchmarks.
In April 2026, Meta Superintelligence Labs released Muse Spark, the company’s first proprietary closed-weight model, signalling a new strategic direction alongside the open-weight Llama line.








