> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ratiofx.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Key Concepts

> Core terminology and concepts used across Ratio's documentation

Use this page as a quick reference for Ratio-specific terms. Each concept links to the relevant documentation section for deeper detail.

<AccordionGroup>
  <Accordion title="Stablecoin Orchestration Layer (SOL)">
    Ratio's complete middleware stack. The SOL abstracts stablecoin FX, liquidity management, and cross-border settlement into a single API integration. It consists of six components: On-Ramp, FX Engine, Liquidity Hub, Yield Engine, Off-Ramp, and Communication Layer.

    See [How It Works](/how-it-works) for the full architecture.
  </Accordion>

  <Accordion title="Corridor">
    A currency pair that Ratio supports for FX conversion. Each corridor connects two stablecoins — for example, the USD-IDR corridor converts between USDT and IDRX. Corridors are configured independently with their own oracle feeds, fee schedules, and liquidity pools.

    See [Corridors](/corridors) for available corridors.
  </Accordion>

  <Accordion title="FX Engine">
    The core execution component of Ratio. The FX Engine takes a swap request, fetches real-time oracle prices, constructs a quote with the appropriate spread, and executes the atomic swap on-chain. It mirrors how institutional FX dealer desks operate — using real market data and rules-based pricing rather than AMM bonding curves.

    See [Oracle-based pricing](/features/oracle-pricing) for how pricing works.
  </Accordion>

  <Accordion title="Oracle">
    An external price feed that provides real-time FX rates to the protocol. Ratio uses Pyth Network as its primary oracle source, with Web2 FX API fallbacks for redundancy. Oracle prices anchor every quote to real market rates.
  </Accordion>

  <Accordion title="Liquidity pool">
    A single-sided, per-currency pool of stablecoins that provides depth for FX execution. Each supported stablecoin (USDT, IDRX, tnSGD, MYRC) has its own dedicated pool. Pools are funded by Liquidity Providers (LPs) and managed by the Liquidity Hub.

    See [Liquidity and pools](/features/liquidity-and-pools) for pool architecture.
  </Accordion>

  <Accordion title="Liquidity Provider (LP)">
    An entity that deposits stablecoins into Ratio's liquidity pools. LPs earn a share of FX swap fees proportional to their deposit. Ratio supports both institutional LPs (stablecoin issuers, market makers) and strategic capital providers.

    See [LP participation](/partners/lp-participation) for details on becoming an LP.
  </Accordion>

  <Accordion title="kToken">
    A receipt token issued to LPs when they deposit stablecoins. kTokens (e.g., kUSD, kIDR) represent the LP's share of the pool and automatically accrue swap fee revenue. kToken balances increase over time as the pool earns fees — no manual claiming required.
  </Accordion>

  <Accordion title="Spread">
    The difference between the buy and sell price on a quote. Ratio's spread is constructed dynamically based on market conditions. It reflects the cost of providing instant execution while maintaining pool health. Spreads are typically in the single-digit basis points range for major corridors.

    See [Fee Structure](/features/fee-and-revenue) for fee and spread details.
  </Accordion>

  <Accordion title="Atomic settlement">
    Every FX swap on Ratio settles in a single on-chain transaction on the Kaia blockchain. There is no counterparty risk, no T+ delay, and no possibility of partial settlement — either the full swap executes or nothing happens.

    See [Atomic settlement](/features/atomic-settlement) for technical details.
  </Accordion>

  <Accordion title="Circuit breaker">
    An automated safety mechanism that adjusts or restricts trading when market conditions deteriorate. Circuit breakers widen spreads, limit trade direction, or pause trading entirely based on oracle health and pool conditions — protecting both LP capital and partner execution quality.

    See [Risk management](/features/risk-management) for how circuit breakers work.
  </Accordion>

  <Accordion title="Rebalancing">
    The process by which Ratio maintains healthy inventory levels across its pools. When FX flows create imbalances (e.g., too many sells of USDT deplete the USDT pool), the protocol coordinates rebalancing via external market makers and OTC partners to restore target levels.

    See [Risk Management](/features/risk-management) for how rebalancing works.
  </Accordion>

  <Accordion title="Partner">
    A business entity integrated with Ratio's API. Partners include PSPs, banks, remittance operators, stablecoin issuers, exchanges, and e-wallet providers. Each partner goes through a structured onboarding process including KYB verification, sandbox testing, and production certification.

    See [Partner types](/partners/partner-types) for the partner ecosystem.
  </Accordion>

  <Accordion title="Quote">
    A price offer returned by the FX Engine for a swap request. Ratio supports two quote types:

    * **Indicative quote** — A reference price for display or planning. No commitment, no reservation.
    * **Firm quote** — A binding, executable price with a short expiry window. Accepting a firm quote triggers the atomic swap.

    See [Integration guide](/integration/overview) for the quote-to-execution flow.
  </Accordion>

  <Accordion title="Webhook">
    An HTTP callback that Ratio sends to your server when an event occurs — such as a swap completing, a settlement confirming, or a quote expiring. Webhooks enable real-time event-driven integration without polling.

    See [Webhooks](/api-reference/webhooks) for event types and payload formats.
  </Accordion>
</AccordionGroup>