// one key, every model

Using every AI, from one key.

One API key. One endpoint. Swap between 15 models -- haiku-4.5-agentic to opus-4.5 -- by changing a single string.

terminal

curl https://api.using.ai/v1/chat/completions \
  -H "Authorization: Bearer $USING_AI_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "sonnet-4.5-thinking",
    "messages": [{"role": "user", "content": "Explain quicksort in one sentence."}]
  }'

Every tier, one call away

A sample of the 15 models in the catalog. Full specs on the models page.

See all models →

haiku-4.5-agentic

Standard

Low-latency agentic model tuned for fast tool-calling loops.

minimax-m2.1

Donator

Balanced general-purpose model for production workloads.

sonnet-4.5-thinking

SuperMaxes

Flagship extended-reasoning model tuned for agentic coding.

opus-4.5

SuperMaxes

Top-tier flagship model for the hardest reasoning tasks.

how it works

One endpoint. Any model.

Every model in the catalog answers to the same request shape. Change the `model` field, keep everything else -- no per-provider client, no separate auth, no rewritten payloads.

swap-models.js

const models = ["haiku-4.5-agentic", "deepseek-r2", "opus-4.5"];

for (const model of models) {
  const res = await using.chat({ model, messages });
  console.log(model, "->", res.choices[0].message.content);
}

pricing

Three tiers, no surprises

See full pricing →

Standard

$3/mo

Fast, cheap models for everyday app traffic.

Donator

$1/mo · promo, then $4/mo

Mid-tier models plus community perks.

SuperMaxes

$10/mo · 7-day free trial

Flagship thinking and agentic models.

using.ai signup

Start free on Standard, or trial SuperMaxes for 7 days. No per-provider contracts, no separate keys.

Start free trial View docs