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What Is the Interledger Protocol?
The Interledger Protocol (ILP) is an open protocol developed originally by Ripple for transferring value across different payment networks and ledgers. Think of ILP as the internet protocol for money — just as HTTP connects different computer networks into a single global web, ILP aims to connect different payment systems (banks, blockchains, mobile money) into a single interoperable payment layer.
ILP is not a blockchain itself. It’s a protocol layer that sits above individual ledgers and enables value to flow between them without requiring each network to directly integrate with every other network.
How ILP Works
ILP uses a system of connectors and conditional transfers to route payments across multiple ledgers:
The Routing Process
- Sender initiates a payment on their local ledger (e.g., a bank account)
- Connectors route the payment across one or more intermediate ledgers, each performing a local transfer
- Receiver receives the payment on their destination ledger (e.g., a different bank, blockchain, or mobile wallet)
Conditional Transfers (Cryptographic Escrow)
ILP secures multi-hop payments using conditional transfers based on cryptographic hash-time-lock contracts (HTLCs). Each connector along the route escrows funds locally, and the payment only completes when the receiver provides a cryptographic proof. If the payment fails at any point, all escrows expire and funds are returned — no party takes on counterparty risk.
ILP’s Role in Ripple’s Enterprise Solutions
While ILP operates independently from Ripple’s products, its architecture directly informs several key enterprise solutions:
- Ripple Liquidity Hub leverages ILP concepts to source crypto liquidity from multiple exchanges while maintaining a single API interface for institutional clients
- RippleNet uses ILP-inspired routing for cross-border payments between partner banks and financial institutions, though it implements proprietary optimizations
- CBDC interoperability — As detailed in our CBDC guide, ILP provides a framework for different central bank digital currencies to interoperate without requiring a common technical standard
Technical Deep Dive: ILP Packet Structure
ILP transactions follow a standardized packet format that enables interoperability between different ledgers:
Core Components
- ILP Address — A hierarchical identifier (e.g., “g.example.alice”) that routes payments across connectors
- Amount — Precise value being transferred, including currency code and amount
- Execution Condition — The SHA-256 hash that must be fulfilled to release funds
- Expiry — Time window for the payment to complete before automatic refund
The packet structure allows connectors to process transfers without needing to understand the underlying ledger’s native transaction format. This abstraction layer is key to ILP’s ledger-agnostic design.
ILP vs XRPL: What’s the Difference?
ILP and the XRPL are separate but complementary:
| Feature | XRPL | ILP |
|---|---|---|
| What it is | A blockchain (distributed ledger) | A protocol (routing layer) |
| Purpose | Store and transfer XRP and tokens | Route payments across any ledger |
| Consensus | RPCA (federated consensus) | No consensus (uses cryptographic escrow) |
| Native asset | XRP | None (ledger-agnostic) |
XRP can serve as a bridge asset within ILP flows — a connector might use XRP to bridge between two fiat currencies — but ILP does not require XRP. This design choice makes ILP maximally flexible and adoptable by institutions that may not want to use cryptocurrency.
Real-World Applications of ILP
- Web Monetization — ILP powers the Web Monetization standard, enabling websites to receive micropayments from visitors as an alternative to ads. The Coil platform used ILP for streaming micropayments to content creators.
- Cross-border payments — ILP can route payments between different banking networks without requiring direct correspondent banking relationships
- Blockchain interoperability — ILP can bridge payments between different blockchains (XRPL, Ethereum, Bitcoin) through connectors
- Mobile money interoperability — connecting different mobile money systems (M-Pesa, GCash) in developing markets
ILP and the W3C
The Interledger Protocol was contributed to the World Wide Web Consortium (W3C) as an open standard. This is significant because it means ILP is not proprietary Ripple technology — it’s an open protocol that anyone can implement, similar to how HTTP is an open standard for the web.
Current Status and Future
ILP development continues through the Interledger Foundation, an independent organization. While consumer-facing adoption has been slower than initially hoped, ILP’s architecture remains influential in payment interoperability discussions. The protocol’s design principles — ledger-agnostic routing, cryptographic security, no central authority — continue to inform how the industry thinks about connecting disparate payment systems.
Conclusion
The Interledger Protocol represents one of Ripple’s most ambitious contributions to financial technology — an open protocol for connecting any payment network to any other. While ILP and XRP are separate (ILP doesn’t require XRP), they complement each other: ILP provides the routing layer, and XRP provides instant liquidity for bridging between currencies. Together, they form a vision for a truly interconnected global payment system.
This article is for informational purposes only and does not constitute financial advice. Always do your own research before making investment decisions.