Comprehensive side-by-side LLM comparison
. Both models have their strengths depending on your specific coding needs.
OpenAI
GPT-5.1 Instant, released by OpenAI in November 2025, is a low-latency variant from the GPT-5.1 family optimized for fast response times and high-throughput workloads. It targets real-time applications, conversational assistants, and production APIs where response speed is a primary requirement alongside GPT-5.1-generation reasoning quality.
OpenAI
OpenAI o3-pro, released by OpenAI in June 2025, is an extended reasoning model from the o3 family that applies more compute per response to deliver deeper, more thorough answers on complex problems. It features a 200K token context window, 100K maximum output tokens, and vision capabilities. o3-pro targets research-grade reasoning tasks, extended coding sessions, and applications where accuracy on difficult problems justifies higher inference cost and latency.
4 months newer

o3 Pro
OpenAI
2025-06-10

GPT-5.1 Instant
OpenAI
2025-11
Context window and performance specifications
Available providers and their performance metrics
GPT-5.1 Instant
o3 Pro
OpenAI
GPT-5.1 Instant
o3 Pro
GPT-5.1 Instant
o3 Pro