Claude Opus 4.8 vs GPT-5.4

Claude Opus 4.8 and GPT-5.4 are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Claude Opus 4.8, from Anthropic, has a 1,000,000-token context window, costs from $5.00/1M input and $25.00/1M output tokens across 3 providers and scores 41.8 on the Artificial Analysis Intelligence Index.

GPT-5.4, from OpenAI, has a 1,050,000-token context window, costs from $2.50/1M input and $15.00/1M output tokens across 2 providers and scores 39.0 on the Artificial Analysis Intelligence Index.

GPT-5.4 is the cheapest on input, 2× cheaper than the next model, GPT-5.4 has the largest context window, Claude Opus 4.8 scores highest for intelligence, Claude Opus 4.8 leads on coding and GPT-5.4 has the highest throughput.