Fastest LLM API — Speed Comparison

LLM API speed is measured by two key metrics: Time to First Token (TTFT) and throughput (tokens per second). Here's how all models compare:

Fastest by TTFT (time to first token):

Fastest by throughput (tokens/second):

When speed matters most: Real-time chat interfaces, autocomplete, streaming code generation, and any application where users are waiting for a response. For background processing and batch jobs, throughput matters more than TTFT.

Tip: Smaller models are generally faster. If your task doesn't require top-tier reasoning, a model like GPT-4.1 Mini or Gemini Flash will give you much better latency.