---
title: Overview
description: Understanding the Kora fee abstraction layer for Solana
---

## What is Kora?

Kora is a **fee abstraction layer** for Solana that lets users pay transaction
fees with SPL tokens instead of SOL (or avoid transaction fees altogether). It's
a JSON-RPC server that acts as a paymaster, sponsoring Solana network
transaction fees while accepting payment in tokens your application supports.

**The Problem**: Users need SOL to pay transaction fees on Solana, creating
friction for apps where users primarily hold other tokens (e.g., a Payments
wallet that only uses USDC or a Game that only transacts in BONK, etc.).

**The Solution**: Kora node operators accept fee payments in SPL tokens, verify
& sign transactions, and pay network fees with their own SOL—creating a gasless
experience for users.

### Example Use Cases

- **Neobanks**: Let users send USDC without needing SOL for fees
- **Gaming**: Players spend in-game tokens for all transactions
- **Liquid Staking**: Enable users of your dApp to hold/use your liquid staking
  tokens rather than Native SOL
- **Loyalty Rewards**: Reward users with a certain number of subsidized fees
  based on their loyalty level

### Key Features

- **Secure**: Configurable validation rules for programs, tokens, and accounts
- **Flexible Pricing**: Support multiple fee payment tokens with real-time
  pricing
- **Easy Deployment**: Ready-to-deploy
  [Kora CLI crate](https://crates.io/crates/kora-cli)
- **Developer Friendly**: JSON-RPC API with CLI and TypeScript SDK for seamless
  interaction with Solana Kit
- **Production Ready**: Built-in rate limiting, monitoring, and security
  features

### How It Works

Kora nodes operate as middleware between your application and Solana. All
transactions on Solana require a fee payer to sign the transaction and cover
network transaction fees in SOL. Additionally, transactions may need signatures
from other wallets depending on the program logic (e.g., token transfers require
the token owner's signature).

Kora introspects Solana transactions before they are sent to the network,
ensures they meet the node's configured security requirements, and verifies the
transaction includes an adequate SPL token payment instruction to the node
operator. Once verified, Kora co-signs the transaction as the fee payer and
returns the fully-signed transaction to the application for network submission.

### Kora Transaction Flow

1. **User initiates** a transaction
2. **App builds** a transaction (with a token payment instruction to the Kora
   node operator)
3. **User signs** the transaction
4. **App sends** the signed transaction to a Kora node operator
5. **Kora validates** the transaction against configured rules (allowed
   programs, tokens, etc.) and verifies that the payment is adequate to cover
   network fees (based on current market prices via an Oracle)
6. **Kora signs** the validated transaction as fee payer and returns it to the
   App
7. **App sends** the Kora-signed transaction to Solana for processing
8. **Solana processes** the transaction: SPL tokens flow to the node operator,
   SOL fees are paid by Kora, and the user's transaction is processed
9. **App confirms** the transaction landed successfully and notifies the user

The user successfully completes their transaction using only SPL tokens, while
Kora handled all SOL-denominated network fees.

![Kora Transaction Flow](/assets/docs/tools/kora/kora.svg)

## Key Terminology

- **Fee payer**: The signer account of a Solana transaction that covers the
  network costs associated with processing the transaction on-chain.
- **Gas** (or gas fees): Costs associated with sending and landing transactions
  on Solana (paid in SOL).
- **Gasless Relayer**: A service that facilitates blockchain transaction on
  behalf of users without requiring them to directly pay gas fees (Kora is a
  gasless relayer).
- **JSON-RPC**: A stateless, lightweight, remote procedure call (RPC) protocol
  that uses JSON (JavaScript Object Notation) for data serialization. It enables
  communication between a client and a server by allowing the client to invoke
  methods on the server as if they were local functions.
- **Oracle**: A service that provides real-time price data for tokens.
- **Paymaster**: A service or account that pays transaction fees on behalf of
  users, typically in exchange for payment in alternative tokens or currencies
  (Kora node operators are paymaster).
- **Rent**: A deposit required by Solana to keep accounts active on the
  blockchain. Rent can be reclaimed when accounts are closed.

## Get Started

Choose your path:

### I want to try Kora quickly

**[→ Quick Start Guide](/docs/tools/kora/getting-started/quick-start)**

Get a local Kora server running and see fee abstraction in action in under 10
minutes.

---

### I want to run a Kora node

**[→ Node Operator Resources](/docs/tools/kora/operators)**

Set up and deploy your own Kora server to sponsor transactions for your
application.

---

### I want to use Kora in my app

Add fee abstraction to your Solana application using the Kora SDK. The
recommended approach is to use `createKitKoraClient()`, which integrates with
Kit's plugin architecture and handles transaction planning, fee estimation,
payment injection, and submission automatically.

**[→ Kit Client Guide](/docs/tools/kora/guides/kit-client)** - Build gasless
transactions with the Kit client

For lower-level control, see the
[Full Transaction Flow](/docs/tools/kora/guides/full-demo) guide using
`KoraClient` directly, or the [API Reference](/docs/tools/kora/json-rpc-api) for
all available client options.

---

## Need Help?

- **[Solana Stack Exchange](https://solana.stackexchange.com/)** - Ask questions
  with the `kora` tag
- **[GitHub Issues](https://github.com/solana-foundation/kora/issues)** - Report
  bugs or request features