OpenAIExact tokenizer
GPT-5.4 mini API price
OpenAI charges $0.75 per 1M input tokens and $4.5 per 1M output tokens. Context window 400,000 tokens. A 10k-in / 2k-out request is about $0.0165.
Who uses GPT-5.4 mini
Catalog prompts in the same model family, plus coding agents from this provider.