Service Tiers — ML Junction docs

Set one canonical service_tier on routing and the gateway translates it to each provider’s native shape. Tiers are a queue-position lever, not a quality lever - the model is identical. If a route can’t serve the requested tier, the request runs on standard and a warning is returned instead of silently downgrading.

Tier · Meaning · Use for
auto · Let the provider pick its best available lane · Default; balanced
standard · Normal shared serving · Most production traffic
priority · Higher scheduling priority, lower tail latency, higher price · Paid users, live UX, checkout
flex · Cheaper, slower, lower priority · Evals, enrichment, background agents

{
  "model": "gpt-5.5",
  "messages": [{ "role": "user", "content": "The user is waiting." }],
  "routing": { "service_tier": "priority" }
}

Pricing is published per tier - flex is cheaper, priority costs more - and the model detail page shows a tier switcher so you can compare before you commit. Tiers do not apply to batch jobs.

Canonical URL: https://mljunction.com/docs/service-tiers