Sei RPC
Sei Overview
Sei is a high-performance Layer 1 blockchain with a focus on speed and efficiency to achieve a Web2-like experience. It runs transactions in parallel and uses an efficient consensus design to handle up to 200,000 TPS, with finality under 400 ms. It's fully EVM-compatible and processes transactions at sub-cent costs.
Interacting With Sei APIs
Sei exposes Ethereum-compatible JSON-RPC methods that allow developers to interact with the network programmatically. You can query blockchain state, send transactions, deploy and interact with smart contracts, and subscribe to real-time events via WebSocket.
You can connect by running your own node or by using a hosted provider such as Quicknode, which offers reliable, low-latency access without the need to manage infrastructure.
The Quicknode Sei documentation is continuously updated, but we recommend cross-referencing with the official Sei documentation for the latest API details.
Make Sei API Calls
The quickest way to start building on Sei is to create a Quicknode endpoint and send your first request. Quicknode provides managed Sei endpoints, offering:
- High reliability — globally distributed infrastructure designed to minimize downtime
- Enhanced performance — optimized latency and request handling for production-grade apps
Visit the QuickStart page to create your endpoint and send your first request.
Supported Networks
Quicknode provides access to the following Sei networks:
Quicknode's Sei Pacific endpoints provide full archive data access starting from block height 1 (genesis).
For blocks >= 78309999:
Use the x-cosmos-block-height header with REST API requests or specify the height parameter with Tendermint API requests:
Cosmos REST API Example:
curl --location 'https://docs-demo.sei-pacific.quiknode.pro/cosmos/distribution/v1beta1/delegators/sei1xyp8xxely9txewfe7nes2nxrzr0qyrfghrj5cs/rewards' \
--header 'x-cosmos-block-height: 78309999'
Tendermint API Example:
curl --location 'https://docs-demo.sei-pacific.quiknode.pro/block?height=78309999'
For blocks < 78309999:
Use the x-qn-height header for COSMOS SDK APIs and TENDERMINT APIs. If you need to query at a specific historical block, use both x-qn-height and x-cosmos-block-height headers:
Transaction Query Example (block < 78309999):
curl -H 'x-qn-height: 73104809' 'https://docs-demo.sei-pacific.quiknode.pro/cosmos/tx/v1beta1/txs/7E84D96044AB1E382C0CDFAFF85067D1742D69FD8D5010350C87890D9E95C193'
Historical Balance Query Example (specific block < 78309999):
curl 'https://docs-demo.sei-pacific.quiknode.pro/cosmos/bank/v1beta1/balances/sei1vfxlpud2txs7en5z7qgf4qk93e64p7r3qlqjpn' \
-H 'x-qn-height: 73104809' \
-H 'x-cosmos-block-height: 73104809'
For Sei EVM methods:
No special headers are required. The earliest block number for EVM methods is 79123881 (Sei V2 upgrade block).
Complete reference for developers building on Sei with Quicknode:
QuickStart
Get started with Sei quickly. Follow our step-by-step quickstart to set up your endpoint and make your first API request.
Provider Endpoints
Learn how to configure and manage your Sei endpoints for optimal performance and reliability.
API Overview
Explore supported APIs, networks, Quicknode products, and enhanced API features for building powerful applications.
Marketplace
Discover and integrate powerful add-ons and tools from the Quicknode Marketplace to enhance your web3 applications.
Endpoint Security
Secure your endpoints with authentication, whitelisting, and best security practices.
Error Codes
Understand common error codes and troubleshooting steps for Sei API requests.