Quotes

Every order is created against a quote. You cannot create one at "the current rate" — the rate has to be locked first, and the quote is the lock.

Taking a quote

POST /v1/quotes with a side and one of the two legs. The other is derived:

{
  "side": "sell",
  "usdtAmount": "250.000000"
}

side is sell (USDT in, KES out) or buy (KES in, USDT out). Whichever leg you did not supply is the computed one, and it rounds in OnLink's favour — which is why you should always display the amounts from the response rather than your own multiplication.

What comes back

{
  "quoteId": "f1c0a5d2-3b4e-4a71-9c8d-0e1f2a3b4c5d",
  "side": "sell",
  "kesAmount": "32025.00",
  "usdtAmount": "250.000000",
  "rate": "128.10",
  "expiresAt": "2026-09-04T09:31:30.000Z",
  "settlementEstimateSeconds": 1800
}

• rate is KES per USDT, locked for this quote.
• kesAmount always carries 2 decimal places, usdtAmount always 6. Both are strings. See Money.
• expiresAt is when the lock stops being executable.
• settlementEstimateSeconds is a coarse band, not a commitment. Use it to set your user's expectation; do not build a timeout around it.

Single-use, and short-lived

A quote is consumed by the order that uses it. Presenting a spent or expired quote is a 409 with QUOTE_EXPIRED_OR_CONSUMED in the message — not a silent re-quote, because a re-quote would execute at a rate you never saw.

The default window is 90 seconds. It can be configured per partner, so read expiresAt rather than assuming the default; a quote you took under one setting is not proof of the next.

A quote is also side-specific. A buy quote presented to POST /v1/orders/sell is refused with QUOTE_SIDE_MISMATCH.

Practical shape

Take the quote at the moment your user is ready to commit, not when they open the screen. If they hesitate past expiresAt, take a new one and show them the new amounts — that is the whole point of a lock with an expiry.

There is no minimum beyond an amount greater than zero. Your ceilings are per-partner: see Caps and limits.