Axis routing

Add a word to the model name to choose how the exchange ranks the offers. The word is smartest, fastest, cheapest, premium, balanced or economy.

deepseek-v4.1-flash:fastest
deepseek:cheapest
liquid.auto:smartest

The name before the colon is the scope: the models that compete. The word after it is the axis: the ranking. An axis changes only the order. Every offer must still pass your cap, limits and key.

Axis	The offer that wins
`smartest`	The highest published score, whatever the charge.
`fastest`	The highest median output speed that the exchange measured. The charge breaks a tie.
`cheapest`	The lowest estimated charge plus the cost of the predicted wait.
`premium`	Auto: a doubling of the charge must buy 0.5 points.
`balanced`	Auto: a doubling of the charge must buy 2 points.
`economy`	Auto: a doubling of the charge must buy 5 points.

Send a request

from openai import OpenAI

client = OpenAI(base_url="https://router.inference.ai.exchange/v1", api_key="...")

response = client.chat.completions.create(
    model="liquid.auto:smartest",
    messages=[{"role": "user", "content": "Hello"}],
    extra_body={"exchange": {"cap_usd": 0.5}},
)

smartest and the Auto words pay more for a better score, so they need a price bound, such as the cap_usd above. With the CLI, write liquid claude --model liquid/auto:fastest.

Choose the scope

Name before the colon	Models that compete
`architect.basket`, a router model such as `liquid.auto`, a preset	The models that the name has without the axis. The axis sets the ranking.
A served model name, such as `deepseek-v4.1-flash`	That model, across all of its offers.
A creator name, such as `deepseek`	Each model of that creator.

smartest and the Auto words need more than one model, because one model has one score.

Web search

Beta. :web can change without notice, including its price and search services.

web is not an axis. It turns on a web search for the request and combines with any axis. Join the words with +, in any order:

deepseek-v4.1-flash:web
liquid.auto:smartest+web

Only an exchange with a search service key has web search. GET /v1/exchange/features says whether it does. For a request with web, the exchange:

Searches once, for the last user message, before it ranks the offers. It tries TinyFish first, then Exa once.
Puts the results in a system message before the last user message, marked as untrusted text. The earlier messages do not change, so a prompt cache still reads them.
Holds the price of the search with the tokens.
Adds the price of the search to fee_usd and buyer_charge_usd when the job settles with a charge. A referral discount does not reduce it.
Reuses the results, free, when the same workspace repeats the query within five minutes. A tool loop, such as Claude Code or Codex, pays for one search.

Status	Code	When
400	`web_search_needs_text`	The request has no user message with text to search for.
400	`web_search_exceeds_cap`	The cap is not more than the price of the search.
402	`insufficient_balance`	The balance cannot pay for the search and an answer.
503	`web_search_unavailable`	No search service answered. Nothing is charged.

Reference

Same request, two forms

{ "model": "deepseek-v4.1-flash:fastest" }

{
  "model": "deepseek-v4.1-flash",
  "exchange": { "rank": { "strategy": { "kind": "fastest" } } }
}

Axis	`exchange.rank.strategy`
`smartest`	`{"kind":"smartest"}`
`fastest`	`{"kind":"fastest"}`
`cheapest`	`{"kind":"price"}`
`premium`	`{"kind":"auto","preference":"premium"}`
`balanced`	`{"kind":"auto","preference":"balanced"}`
`economy`	`{"kind":"auto","preference":"economy"}`

The word counts as an axis only when the text after the last colon is exactly one of the six words, with a name before it. Otherwise the colon belongs to the model name: llama3:8b is one model name.

How each axis ranks

cheapest is the default ranking of a model and a basket. A wait value of zero ranks on charge alone. See Price and wait.
fastest uses the median output speed over the last 7 days, counted after 5 timed jobs. A difference under 1 token per second is a tie, and the charge decides. An offer with no counted speed ranks last. See How the exchange measures performance.
premium, balanced, economy and smartest rank by Auto Router. smartest is mode version 4 and uses the general score when no offer has a coding score.

Refusals

Status and code	Cause
`400 smartest_needs_several_models`	`smartest` with one model. Use a creator, a router model, a basket or a preset.
`400 strategy_conflicts_with_address`	`premium`, `balanced` or `economy` with one model.
`400 auto_requires_price_bound`	`smartest` or an Auto word with no cap, no cost tier other than `any` and no output-rate ceiling. A router model with a cap of its own does not need one.
`400 axis_conflict`	Another ranking in the same request: another `exchange.rank.strategy` kind, another Auto version, the `x-liquid-policy` header, or `exchange.candidates.creators.allow` with a creator name.
`400 ambiguous_scope`	A name that is both a served model and a creator. Send `architect.basket` with a pattern in `exchange.candidates.models.allow`, such as `deepseek-*`.

See Errors for every code.