Live quote, expiry, spread, slippage, basis points, depth, market maker, RFQ, pre-funding: the 40 terms behind on/off-ramp liquidity, in plain English.
On-ramp and off-ramp liquidity is a provider's ability to convert between local money and stablecoins at the size you need, at a quoted rate, without the price moving against you. This glossary defines the 40 terms behind that sentence, from live quote and expiry to spread, slippage, depth, market makers, and pre-funding.
Every other article in this series uses these definitions. Where a term maps to a field in a BlindPay quote, the field name is listed, so you can check the definition against a real API response. For blockchain basics such as wallet, finality, or gas, see the blockchain payments glossary.
Key takeaways
Nine of the terms below appear as fields in a BlindPay payout quote or payin quote. The table is the short version.
| Term | One-line definition | BlindPay quote field |
|---|---|---|
| Quote ID | The handle you execute against | id |
| Expiry window | How long the price is binding | expires_at (epoch milliseconds) |
| Market rate | The raw exchange rate before the provider's margin | commercial_quotation |
| Quoted rate | The rate after the provider's margin | blindpay_quotation |
| Sender amount | What leaves the paying side | sender_amount |
| Receiver amount | What lands on the receiving side | receiver_amount |
| Request side | Which side the amount you typed is in | currency_type |
| Fee direction | Who absorbs the fee | cover_fees |
| Fee lines | Fees listed apart from the rate | flat_fee, partner_fee_amount, billing_fee_amount |
On-ramp. A service that converts fiat money into stablecoins. Dollars, reais, or pesos go in, and USDC or USDT lands in a wallet. What is a crypto on-ramp and off-ramp covers the basics.
Off-ramp. The reverse: stablecoins go in, and local currency lands in a bank account over a local rail.
Liquidity. The ability to convert at the size you need, at a quoted rate, without moving the price. It is a capability, not a pile of money.
Liquidity depth. How much a provider can convert on one corridor before its rate degrades. Deep means a $50,000 quote prices close to a $500 quote.
Corridor. A currency pair plus a direction, such as USDC to BRL. Depth, spread, and speed are properties of a corridor, not of a provider as a whole.
Payout rail. The local payment system that delivers the money at the end, such as Pix in Brazil, SPEI in Mexico, ACH in the US, or SEPA in Europe.
Payin and payout. A payin is money coming in, a bank transfer converted into stablecoins (the on-ramp side). A payout is money going out, stablecoins converted into fiat and sent to a bank account (the off-ramp side).
Live quote. A binding price for one conversion, calculated when you request it and held for a stated window. It carries an ID and an expiry time. Execute inside the window and you get the quoted numbers.
Quote ID. The identifier you pass when you execute. BlindPay payout quotes start with qu_. Payin quote IDs are passed as payin_quote_id.
Expiry window. How long the quote stays binding. At BlindPay, payout, payin, and transfer quotes expire 5 minutes after creation by default, OTC payin quotes expire in 10 seconds, and SEPA payout quotes can be shorter. The expires_at field holds the deadline in epoch milliseconds, so read it from each response instead of hardcoding a window. The cut-off times reference lists every default.
Market rate. The exchange rate before the provider's margin. On a BlindPay quote this is commercial_quotation.
Quoted rate. The rate you actually convert at. On a BlindPay quote this is blindpay_quotation. The gap between the two is the provider's FX margin.
Sender amount and receiver amount. What leaves one side and what arrives on the other, both in minor units.
Minor units. Amounts written as integers in the currency's smallest unit. 10000 means 100.00. Integers avoid floating point rounding errors.
Request side. Which side of the conversion the amount you send in the request is denominated in. On a BlindPay payout quote, currency_type: "sender" means the stablecoin side and "receiver" means the fiat side. On a payin quote the meaning flips. Stablecoin API quotes explained walks through it.
Fee direction. Who absorbs the fee. With cover_fees: false the fee comes out of what the recipient gets. With cover_fees: true the sender pays it on top.
Firm quote (binding quote). A price the provider commits to execute at, for a stated window. A live quote is a firm quote.
Indicative rate. A price shown for information. The provider does not commit to it, and the conversion settles at whatever the market says later.
Stale quote. A rate calculated some time ago and still on display. The older it is, the further the market has moved, and someone absorbs that move.
Re-quote. A fresh quote requested after the previous one expired. The new numbers can differ, because the market moved in between.
Re-quote delta. The change between an expired quote and its replacement. Large deltas on one corridor are a volatility signal.
Mid-market rate. The midpoint between the price buyers bid and sellers ask in the wholesale market. Public reference rates are a slower version of it: the ECB says its euro reference rates are published around 16:00 CET for information purposes only, and strongly discourages using them for transactions.
Bid and ask. The bid is what a dealer pays to buy a currency from you. The ask is what it charges to sell it to you. The ask is always higher.
Spread. The gap between the market rate and the rate you are quoted, usually written as a percentage or in basis points. You see it before you send.
Slippage. The gap between the rate you were shown and the rate that settled. You see it only after. On a binding quote executed inside its window, slippage is zero.
Basis point (bps). One hundredth of one percent. 50 bps is 0.50%. On $10,000, each basis point is $1.
Flat fee and percentage fee. A flat fee is a fixed charge per transaction. A percentage fee scales with the amount and is usually quoted in basis points.
Partner fee. A markup a platform adds on top of the provider's price. At BlindPay it shows as partner_fee_amount on the quote. See partner fees.
Delivered amount. What actually lands in the recipient's account after the rate and every fee. The only number the recipient cares about.
Liquidity provider. Any party that converts between stablecoins and local currency on demand and delivers the result. What is a liquidity market explains how the role is changing.
Market maker. A firm that continuously quotes both a buy and a sell price and earns the spread between them. Market makers carry inventory and hedge the risk of holding it.
Inventory. Balances of local currency and stablecoins a provider holds ready to fill orders. Inventory is what lets a provider bind a quote on demand.
RFQ (request for quote). A pricing model where a buyer asks several approved liquidity providers for executable prices and picks the best one.
OTC desk. An over-the-counter desk that prices large conversions directly instead of through a public order book. At BlindPay, OTC payin quotes cover BRL to USDT from $5,000 USD equivalent and expire in 10 seconds.
Pre-funding. Parking money in destination-country accounts before you can pay out. It ties up working capital and adds FX risk. No pre-funding in a stablecoin API shows the alternative.
Nostro account. A bank's account held at a foreign bank, in that bank's currency. Correspondent banking runs on them, and they are why the old model needs pre-funding. See correspondent banking vs stablecoin liquidity.
Funding at execution. Paying for each payout from stablecoins at the moment it executes. With a BlindPay payout from your own EVM wallet, you approve the quoted amount and BlindPay pulls it when the payout is created.
Float. The stablecoin balance a business keeps ready to fund upcoming payouts. Smaller than country-by-country pre-funding, because one dollar balance serves every corridor.
Settlement. The moment the recipient has the money with no further steps. For a payout that is when the local rail credits the bank account.
Refund wallet. Where stablecoins go back if a payout cannot be delivered after they were collected. BlindPay refunds to the quote's refund wallet, or to the sending wallet when none is set. On Pix and other non-USD local rails the refund is automatic; USD payouts are refunded after an operator review.
One quote uses most of the glossary at once.
Illustrative example. A company sends 10,000 USDC to a supplier in Brazil. The numbers are made up for the arithmetic, not BlindPay pricing.
| Item | Value | How it is calculated |
|---|---|---|
Market rate (commercial_quotation) | 5.40 BRL per USDC | From the market at request time |
Quoted rate (blindpay_quotation) | 5.373 BRL per USDC | Market rate minus the margin |
| Spread | 0.50%, or 50 bps | (5.40 - 5.373) / 5.40 |
| Spread in money | 270 BRL, about 50 USDC | 10,000 x (5.40 - 5.373) |
| Receiver amount before flat fee | 53,730 BRL | 10,000 x 5.373 |
| Slippage | 0 bps | Executed inside the 5-minute window |
Now change one thing. Say a provider had shown 5.373 as an indicative rate and settled later at 5.370. Slippage would be (5.373 - 5.370) / 5.373 x 10,000, about 5.6 bps, or 30 BRL the supplier never agreed to lose.
Small on one payment. On $2 million a month it is about $1,100, and nobody sees it on the quote screen.
The wholesale market behind these numbers is enormous: the BIS 2025 Triennial Survey measured $9.6 trillion of FX trading per day. Depth on one emerging-market corridor is a much smaller pool, which is why it is worth testing. On/off ramp liquidity with live quotes shows how depth changes quotes by size, and USDC itself is designed to be redeemable 1:1 for US dollars, so the FX question sits on the local-currency side.
Pull one real quote and match each field to the definitions above. The payout quotes docs show a full response, field by field.
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