GPT-4o vs Claude Sonnet 4

These are the two primary workhorses. GPT-4o for breadth and multimodal. Claude Sonnet for writing and long-context.

If you are picking one model for a new production system in 2025, the decision almost always comes down to one of these two. Here is the honest side-by-side.

	GPT-4o	Claude Sonnet 4
Pricing (input/output, $/1M)	$2.50 / $10.	$3 / $15.
Context window	128K tokens.	200K tokens.
Writing quality	Very good.	Slightly better on long-form, editorial tone.
Coding	Excellent for generation. Tight agent loops.	Excellent for review and editing. Great at whole-repo context.
Multimodal	Vision + native voice (Realtime API).	Vision only.
Tool / function use	Mature. Parallel function calls.	Mature. Very reliable schema adherence.
Instruction following	Strong.	Stronger on nuanced, complex instructions.
Latency	Fast.	Fast (slightly slower than 4o on short tasks).

Pick GPT-4o when

Default to GPT-4o when: you need voice or image gen, you are cost-sensitive, or you are tightly integrated with the OpenAI ecosystem.

Pick Claude Sonnet 4 when

Default to Claude Sonnet when: writing quality matters, you have long documents to process, or you need the most reliable function-calling behavior.

Bottom line

In production systems we route between both by task. GPT-4o handles classification, short tasks, and voice; Claude Sonnet handles analysis, long-context, and structured output. You do not have to pick one.

Need help picking — or stitching them together?

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Glossary