OpenAI vs Anthropic vs Google Gemini: Which LLM API Is Best?
Published: November 1, 2026 · 6 min read
Pricing data as of Nov 4, 2026 - verify current rates on the official site before purchase
If you're building an AI app, choosing the right LLM API is one of the biggest decisions you'll make. We tested GPT-5.4, Claude Sonnet 5.5, and Gemini 2.5 Flash on coding, reasoning, and cost, here's what we found.
Quick Comparison
| Feature | OpenAI GPT-5.4 | Anthropic Claude Sonnet 5.5 | Google Gemini 2.5 Flash |
|---|---|---|---|
| Input Price (1M tokens) | $2.50 | $2.00 | $0.30 |
| Output Price (1M tokens) | $15.00 | $10.00 | $2.50 |
| Context Window | 272K standard (1.05M max) | 1M tokens | 1M tokens |
| Best At | General purpose, fast | Writing, code, long context | Cheap, very long context |
OpenAI GPT-5.4: The Safe Default
GPT-5.4 is OpenAI's workhorse model for production apps: it's fast, well-documented, and works for almost every use case, with a 272K token context window (requests beyond that are billed at twice the standard rate). The ecosystem of SDKs, tutorials, and third-party tools around OpenAI is unmatched.
Pros: Best tool calling, fastest ecosystem, great out-of-the-box results.
Cons: Not the cheapest, and context window is smaller than competitors.
Anthropic Claude Sonnet 5.5: Best for Code & Writing
Claude Sonnet 5.5 (Anthropic's latest, announced September 2026) leads on coding and long-form writing — $2 per 1M input tokens and $10 per 1M output tokens, with a 1M token context window. If you're building a code assistant, writing long documents, or working with long context, Claude is the best choice.
Pros: Best code quality, long context, very reliable.
Cons: Output still costs about 4x Gemini 2.5 Flash ($10 vs $2.50 per 1M tokens).
Google Gemini 2.5 Flash: Best Cheap Long Context
Gemini 2.5 Flash offers a 1M token context window at a fraction of the price of OpenAI and Claude. If you need to process huge documents, entire codebases, or video/audio inputs, Gemini is the clear value choice.
Pros: Cheapest, 1M token context, great for multimodal.
Cons: Code quality is slightly behind GPT and Claude.
Who Should Pick Which?
- If you want the safe, well-documented default: Choose OpenAI
- If you build coding/writing apps and want the best quality: Choose Anthropic Claude
- If you need long context on a budget: Choose Google Gemini
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