The language of crypto & payments.

Paymaster

In ERC-4337, a contract that can participate in paying a UserOperation’s gas costs under its own validation and charging policy.

Also known as paymasters

Payment fraud prevention

The controls used to reduce unauthorized, deceptive or abusive payment activity through prevention, detection and review.

Also known as fraud prevention

Payment gateway

Technology that connects a merchant’s checkout or payment request to the systems used to accept and process a payment.

Also known as payment gateways

Payment monitoring

The ongoing observation of payment operations and supporting systems to identify status changes, failures or deviations from expected behavior.

Payment reconciliation

The process of matching payment and accounting records across systems, explaining differences and documenting corrections or unresolved exceptions.

Also known as reconciliation

Payment service provider

An individual or organization providing payment services, with its exact role and regulatory status determined by its activities and the applicable framework.

Also known as PSP

Payment settlement

The completion of a transaction or processing stage through a transfer of funds or assets intended to discharge the relevant obligations.

Also known as settlement

Payout

A disbursement of funds to an intended recipient, such as a transfer from a payment provider’s available merchant balance to a bank account.

Also known as payouts

PayPal USD

A US dollar-referenced stablecoin branded by PayPal and issued by Paxos, with backing and redemption governed by the issuer’s terms.

Also known as PYUSD

PCI DSS

The Payment Card Industry Data Security Standard: a baseline of technical and operational requirements for protecting payment account data in its defined scope.

Also known as Payment Card Industry Data Security Standard

Point of sale

The system or setting where a merchant records a sale and accepts the customer’s payment, often in person.

Also known as POS, POS system

Price volatility

The degree to which an asset’s price varies over a period, described using a chosen observation interval and measurement method.

Also known as volatility

Purchase order

A buyer-issued commercial document describing the goods or services being ordered and the agreed or proposed purchasing details.

Also known as PO, purchase orders

QR code

A two-dimensional machine-readable code that encodes information such as text, a URL or a structured payment request.

Also known as QR codes

Rate limiting

A mechanism that restricts how much activity a client, account or resource may perform during a defined period or under another usage policy.

Also known as API rate limit, rate limits

Recurring payment

A payment made repeatedly under an ongoing arrangement, with timing, amount and authorization determined by that arrangement.

Also known as recurring payments

Refund

A return of money or value to a customer in connection with an earlier payment, usually initiated under the merchant’s or provider’s refund process.

Also known as refunds

REST API

An application interface designed using Representational State Transfer principles, including a uniform interface and stateless client-server interactions.

Also known as RESTful API

Retainer fee

A professional-service fee arrangement whose meaning depends on the engagement: it may secure availability or describe an advance applied to future work.

Also known as retainer

Revenue recognition

The accounting determination of when and in what amount revenue is recorded under the applicable reporting framework.

Rollup

A blockchain scaling design that executes transactions outside a base layer and submits the information required by its settlement and verification mechanism to that layer.

Also known as rollups

Security deposit

Money or value held as security for specified obligations, with any permitted deductions and return conditions determined by the agreement and applicable law.

Also known as security deposits

Service-level agreement

An agreement defining measurable service commitments, their scope and the remedies or procedures that apply when those commitments are not met.

Also known as SLA

Smart contract

A program deployed to a blockchain that applies its code and state-transition rules when invoked under that network’s execution model.

Also known as smart contracts