diff --git a/11-payment-encoding.md b/11-payment-encoding.md
index 40d16a6d4..6a5e8f8e9 100644
--- a/11-payment-encoding.md
+++ b/11-payment-encoding.md
@@ -7,6 +7,7 @@ over Lightning.
 
   * [Encoding Overview](#encoding-overview)
   * [Human-Readable Part](#human-readable-part)
+  * [Keysend Invoice Overview](#keysend-invoice-overview)
   * [Data Part](#data-part)
     * [Tagged Fields](#tagged-fields)
     * [Feature Bits](#feature-bits)
@@ -60,6 +61,15 @@ The following `multiplier` letters are defined:
 * `n` (nano): multiply by 0.000000001
 * `p` (pico): multiply by 0.000000000001
 
+# Keysend Invoice Overview
+
+Keysend invoice is a subset of standard invoice with the following differences: 
+- prefix is set to `lnks` + BIP-0173 currency prefix (e.g. `lnksbc` for Bitcoin mainnet,
+   `lnkstb` for Bitcoin testnet, `lnkstbs` for Bitcoin signet, and `lnksbcrt` for
+   Bitcoin regtest).
+- `p` tagged field MUST NOT be included.
+- `amount` and `multiplier` MUST NOT be included.
+
 ## Requirements
 
 A writer: