Arbitrum Sepolia RPC Endpoints & API | OnFinality

Arbitrum’s Sepolia Testnet

Connect to Arbitrum Sepolia in seconds with OnFinality RPC endpoints, request analytics, scalable rate limits, and 99.99% uptime for production Web3 apps.

Arbitrum’s Sepolia Testnet

Create RPC Endpoint

Arbitrum Sepolia RPC Endpoint

The below example uses the public API endpoint*. This endpoint is only suitable for testing. To avoid rate limiting and service interruption, sign up now to get your own API key.

* The public endpoint is rate limited

RPC API Service

RPC API Features

ArchiveTrace

Build on Arbitrum Sepolia with OnFinality RPC Endpoints

Arbitrum Sepolia is the official testnet for Arbitrum One, an Ethereum Layer 2 optimistic rollup. It provides a safe environment for developers to test smart contracts, dApps, and cross-chain interactions before deploying to mainnet. OnFinality offers managed RPC endpoints for Arbitrum Sepolia, giving you reliable access to the testnet without running your own node.

What is Arbitrum Sepolia?

Arbitrum Sepolia is a testnet that mirrors the functionality of Arbitrum One. It uses the same Nitro technology stack and is connected to Ethereum's Sepolia testnet. Developers use it for:

Smart contract testing and debugging
QA and staging releases
Wallet integration testing
Backend validation
Cross-chain interaction experiments

Why Use OnFinality for Arbitrum Sepolia RPC?

OnFinality provides authenticated RPC endpoints for Arbitrum Sepolia, offering:

Stable access: Dedicated endpoints with clearer usage limits compared to public RPCs.
Advanced features: Support for archive data and trace API, enabling deep historical queries and debugging.
Observability: Request analytics and usage visibility through the OnFinality dashboard.
Scaling path: Upgrade to higher-capacity plans or dedicated nodes as your project grows.

Key Facts About Arbitrum Sepolia on OnFinality

Network environment: Testnet
RPC protocol: EVM JSON-RPC
Transport: HTTP and WebSocket
Advanced access: Archive and trace available
Common users: Contract testing, QA, staging, wallet integration, backend validation
Regions: Available through OnFinality global infrastructure

How to Connect to Arbitrum Sepolia with OnFinality

Create or sign in to your OnFinality account.
Select Arbitrum Sepolia from the supported networks list.
Create an API endpoint or deploy a dedicated node (if supported).
Test the endpoint using eth_blockNumber.
Monitor request usage, errors, and limits before moving critical traffic.

When to Use Private RPC Instead of Public

Public Arbitrum Sepolia RPC endpoints (like https://sepolia-rollup.arbitrum.io/rpc) are suitable for quick tests. However, for team projects, backend services, or higher-volume workloads, authenticated OnFinality endpoints provide better reliability, analytics, and support.