GPT-5.5 vs Grok 4.3

Pick two tools from the same category to compare side-by-side.

	GPT-5.5 OpenAI's flagship frontier model, positioned as a new class of intelligence for coding and professional work.	Grok 4.3 xAI's flagship API model, billed as its most intelligent and fastest, with strong agentic tool calling.
Category	model	model
Vendor type	commercial	commercial
Pricing	usage	usage
Strengths	+ OpenAI's recommended model for complex reasoning and coding + 1M-token context window with up to 128K output tokens + Generally available via the OpenAI API with listed pricing of $5 input / $30 output per million tokens	+ Aggressive pricing ($1.25 input / $2.50 output per million tokens) for a 1M-context flagship + Vendor-reported leadership in agentic tool calling and instruction following + Companion multi-agent variant (grok-4.20-multi-agent) targeted at agentic workloads
Tradeoffs	− Most expensive tier in OpenAI's lineup; GPT-5.4 is positioned as the more affordable option for similar work − API-only commercial model; no open weights	− Stated knowledge cutoff of November 2024 is older than competing flagships − Rapid model churn; xAI retired eight legacy models (including grok-3) in May 2026, so pinned integrations need active migration
Used in stacks	0	0