Question 1

Sepolia Testnet: How Do You Connect and Verify Your RPC Setup?

Accepted Answer

Sepolia is Ethereum's primary public testnet for application development. When developers search for "sepolia," they usually need one of three things: the correct chain settings to add the network to a wallet, a working RPC endpoint to deploy and test contracts, or a way to diagnose why a test transaction is not behaving as expected.

The essential Sepolia settings are stable and widely documented: chain ID `11155111`, currency symbol `ETH`, and block explorer `https://sepolia.etherscan.io`. What changes between setups is the RPC endpoint you point your tooling at. Public endpoints are fine for quick checks, but they can be rate-limited, inconsistent under load, or missing the method support your test suite needs.

This page focuses on the connection and verification workflow: which settings to use, how to confirm your endpoint is healthy, and when to move from a shared public URL to a managed or dedicated RPC service. For a broader endpoint reference, see the [Ethereum Sepolia RPC endpoint page](/networks/eth-sepolia).

Question 2

What Are RPC Nodes and How Do You Choose One for Production Apps?

Accepted Answer

An RPC node is a server running blockchain client software that answers Remote Procedure Call (RPC) requests from your application. Your wallet, dApp, backend indexer, or trading bot sends a JSON-RPC request to an RPC endpoint, and the node reads chain state, simulates calls, or broadcasts signed transactions on your behalf.

Most teams do not need to operate an RPC node themselves. The real decision is how to source one: a free public endpoint, a managed RPC API, or a dedicated node you control. Each option trades off cost, operational effort, privacy, method support, and how much load you can push through it.

This page explains how RPC nodes work, what separates a healthy node from a fragile one, and how to pick the right setup for your workload. Where you need managed endpoints or a dedicated node, OnFinality provides RPC API access and dedicated node infrastructure across supported networks.

Question 3

Polymarket API Documentation: Which API Do You Actually Need?

Accepted Answer

If you searched for Polymarket API documentation, you probably want to do one of three things: read live market and event data, stream order books and trades, or place and manage orders programmatically. Those jobs are served by different APIs, and the fastest path is to identify which one matches your workload before you read a single endpoint reference.

At a high level, the Polymarket surface splits into a public read side (markets, events, series, order books, price history, search) and an authenticated trading side (orders, portfolio, balances, and private WebSocket streams). Third-party data products also exist for historical and analytics use cases. Each has its own base URL, auth model, and rate behavior, so mixing them up is the most common source of confusion.

There is also an on-chain layer. Polymarket activity settles on Polygon, which means teams that need to verify settlements, index wallet activity, or reconcile their own records eventually need a Polygon RPC endpoint alongside the REST APIs. OnFinality provides [RPC API access](/api-service) and [dedicated node infrastructure](/dedicated-node) for Polygon and other [supported networks](/networks) when your integration outgrows public endpoints.

This page maps the documentation landscape, shows how to pick the right API for your workload, and covers the operational details — keys, pagination, WebSockets, and Polygon RPC — that the reference docs assume you already know.

Question 4

Polymarket API: CLOB, Gamma, and the Onchain Layer Behind Them

Accepted Answer

The Polymarket API is not a single endpoint. It is a set of HTTP and WebSocket interfaces that sit on top of a prediction market deployed on Polygon. Developers typically touch two layers: the market-data layer (Gamma-style REST endpoints for events, markets, and metadata) and the trading layer (the CLOB API for order books, orders, trades, and authenticated account actions). Both are documented by Polymarket, and both are separate from the blockchain RPC you use to read the underlying contracts.

That separation matters. If you are building a dashboard, a research pipeline, or a trading bot, you will probably call the market-data and CLOB APIs for quotes and order flow, and you will call a Polygon RPC endpoint when you need to verify settlement, read onchain positions, watch token transfers, or reconcile what the API reports against chain state. Mixing the two up is the most common source of confusion for teams integrating Polymarket for the first time.

This page explains what each layer is for, how to decide which one your workload needs, and where a reliable Polygon RPC endpoint fits. OnFinality provides RPC API access and dedicated node infrastructure for Polygon and many other networks, which is relevant when your Polymarket integration needs onchain reads at production volume.

Question 5

Polygon Mainnet RPC: Chain Settings, Endpoint, and Connection Checks

Accepted Answer

Polygon Mainnet is the proof-of-stake, EVM-compatible chain identified by chain ID 137. If you searched for "polygon mainnet," you most likely need to connect a wallet, a dApp, or a backend service to it and want the correct chain settings and a working RPC endpoint without guessing.

This page gives you the chain settings first, then a public OnFinality endpoint you can test immediately, then the checks that separate a quick demo from a production-ready connection. It also explains when a public endpoint is enough and when a dedicated node or managed RPC plan makes more sense.

Polygon Mainnet is not the same as Polygon Amoy, the testnet. Keep the two separate in your config: the mainnet chain ID is 137, while Amoy uses 80002. Mixing them up is one of the most common reasons a deployment looks connected but never confirms a transaction.

Question 6

Mainnet Faucet: What It Is and When You Actually Need One

Accepted Answer

A mainnet faucet is a service that sends small amounts of real, mainnet tokens to a wallet address so you can pay gas or test a transaction on a production network. Unlike testnet faucets, which dispense valueless test tokens, mainnet faucets distribute assets that have market value, so they are rate-limited, captcha-protected, and usually capped at tiny amounts.

Developers typically look for a mainnet faucet when they need a few cents of native gas to deploy a contract, move a token, or verify a wallet flow on a live chain. The tradeoff is that mainnet faucets are scarce and heavily abused, so most teams treat them as a last resort rather than a primary funding path.

This page explains what mainnet faucets actually dispense, how to tell whether you need one or a testnet faucet, and how to configure your RPC connection so the tokens you receive are usable. If you are building on a chain that OnFinality supports, you can pair a faucet drip with a reliable RPC endpoint from the [supported RPC networks](/networks) list.

Question 7

Chain ID: What It Is and How to Verify It on Any EVM Network

Accepted Answer

A **chain ID** is the integer that tells an EVM client which blockchain it is talking to. Wallets, RPC endpoints, and signing libraries all read it, so a mismatch is one of the most common reasons a transaction fails or a dApp appears to be on the wrong network.

The fastest way to confirm the chain ID of an endpoint is to call `eth_chainId` and compare the hex result to the value you expect. For example, a BNB Smart Chain mainnet endpoint should return `0x38` (56), while a BNB Chain Testnet endpoint should return `0x61` (97). If the value differs, you are connected to a different chain than your app assumes.

This page explains what the chain ID protects against, how to read it from a wallet or an RPC endpoint, and how to keep it consistent across local development, CI, and production. It also covers the operational side: why the endpoint you choose matters when you need to verify chain identity reliably, and when a managed RPC service or dedicated node is a better fit than a public endpoint.

Question 8

UniCrypt (UNCX): What It Is and How to Build Around Its Contracts

Accepted Answer

UniCrypt, now branded as UNCX Network, is a multi-chain DeFi toolkit for token teams. Its core products include liquidity lockers, token vesting schedules, staking and farming reward programs, and a token minter. The project launched in 2020 and its governance utility token trades under the ticker UNCX (older references use UNC).

If you searched for "unicrypt" because you are integrating with its contracts, the practical question is usually not what the brand does, but how to read and write to its contracts reliably across Ethereum, BNB Chain, Base, Arbitrum, Solana, Polygon, and other supported networks. That means a dependable JSON-RPC endpoint, correct chain settings, and a way to debug failed transactions.

This page explains the UNCX product surface from a developer's point of view, then focuses on the infrastructure decisions: which RPC methods you need, how to handle multi-chain reads, and when a shared public endpoint is enough versus when a dedicated node makes more sense. OnFinality provides RPC API access and dedicated node infrastructure for many of the networks UNCX supports; check [supported RPC networks](/networks) and [RPC pricing](/pricing/rpc) before you commit to an architecture.

Question 9

What Is the Sepolia Testnet and How Do You Connect to It?

Accepted Answer

The Sepolia testnet is Ethereum's primary proof-of-stake test network. It mirrors mainnet behavior closely enough to deploy contracts, run integration tests, and rehearse upgrades without spending real ETH. Developers use it because it is stable, widely supported by tooling, and has a long support horizon compared with retired testnets.

Connecting to Sepolia is mostly a configuration exercise: you need an RPC endpoint, the correct chain ID (11155111), a funded test account, and a block explorer for verification. The friction usually comes from choosing an endpoint that can handle your workload, keeping test funds flowing, and debugging failures that look like mainnet bugs but are actually testnet configuration issues.

This page gives you the chain settings, a decision guide for endpoint choice, request examples, and a debugging path. It also explains where a managed RPC API or dedicated node fits when public endpoints are not enough.

Question 10

Free Crypto Faucets: Testnet Tokens, Safety, and RPC Setup

Accepted Answer

A crypto faucet is a service that dispenses small amounts of cryptocurrency. For developers, the useful kind is a testnet faucet: it sends free test tokens (for example Sepolia ETH or testnet POL) so you can deploy contracts, run integration tests, and exercise wallet flows without spending real funds. The other kind, a mainnet faucet that pays tiny amounts of real coins for tasks or captchas, is mostly a consumer-earning product and carries more risk than value for development work.

This page focuses on the developer path. You will see how testnet faucets work, how to judge whether a faucet is legitimate, how to wire the tokens into a working RPC endpoint, and what to do when a faucet claim fails or the balance never appears. Faucet tokens have no market value, so treat every faucet request as a test-environment action, not an investment.

If you are building on a supported network, OnFinality provides RPC API access and dedicated node infrastructure that you can pair with any testnet faucet. Check [RPC pricing](/pricing/rpc) and [supported RPC networks](/networks) to see what is available for your chain.

Question 11

Alchemy Polygon RPC: What to Evaluate Before You Commit

Accepted Answer

If you are searching for "alchemy polygon rpc," you likely need to connect an application to Polygon PoS and are weighing whether Alchemy's hosted JSON-RPC service is the right fit. Alchemy provides authenticated HTTPS and WebSocket endpoints for Polygon mainnet and the Amoy testnet, tied to an app and API key. That model works well for teams that want a managed provider with a dashboard, SDKs, and enhanced APIs, but it also introduces key management, plan limits, and vendor-specific tooling into your architecture.

This article is an evaluation guide, not a setup tutorial. It explains how Alchemy's Polygon endpoint model works, what to check before you standardize on it, and where an alternative like OnFinality's [Polygon RPC API](/networks/polygon) or [dedicated Polygon nodes](/dedicated-node) may fit better. Use it to make a decision, then follow the provider's own docs for exact endpoint strings and current plan details.

For a broader view of how RPC providers differ, see [how to choose an RPC provider](/rpc-assistant/how-to-choose-an-rpc-provider). For current OnFinality plans, check [RPC pricing](/pricing/rpc) and the full list of [supported RPC networks](/networks).

Question 12

Hyperliquid Testnet: RPC Endpoint, Faucet, and Chain Settings

Accepted Answer

Hyperliquid has a public testnet for both its trading layer (HyperCore) and its EVM (HyperEVM). If you searched for "hyperliquid testnet", you likely need one of three things: a testnet RPC endpoint to connect a wallet or app, testnet HYPE or mock USDC from a faucet, or the correct chain settings for HyperEVM testnet (chain ID 998). This page gives you the practical reference first, then explains how to debug common testnet issues and when a managed RPC service is worth using.

OnFinality provides RPC API access and dedicated node infrastructure for supported networks. For Hyperliquid testnet, check the [supported RPC networks](/networks) page for current availability and endpoint details, and see [RPC pricing](/pricing/rpc) if you need a managed endpoint for development or CI. The official Hyperliquid testnet app and docs remain the source of truth for faucet rules and protocol behavior.

API Service

Dedicated Nodes

Enterprise Nodes

Indexer Services

Network Prototyping Tools

Staking & Validators

AI Agent

RPC documentation entries

Sepolia Testnet: How Do You Connect and Verify Your RPC Setup?

What Are RPC Nodes and How Do You Choose One for Production Apps?

Polymarket API Documentation: Which API Do You Actually Need?

Polymarket API: CLOB, Gamma, and the Onchain Layer Behind Them

Polygon Mainnet RPC: Chain Settings, Endpoint, and Connection Checks

Mainnet Faucet: What It Is and When You Actually Need One

Chain ID: What It Is and How to Verify It on Any EVM Network

UniCrypt (UNCX): What It Is and How to Build Around Its Contracts

What Is the Sepolia Testnet and How Do You Connect to It?

Free Crypto Faucets: Testnet Tokens, Safety, and RPC Setup

Alchemy Polygon RPC: What to Evaluate Before You Commit

Hyperliquid Testnet: RPC Endpoint, Faucet, and Chain Settings

Never Worry about Infrastructure Again

Supported Networks

Product

Company

Resources

OnFinality RPC Assistant

RPC documentation entries

Sepolia Testnet: How Do You Connect and Verify Your RPC Setup?

What Are RPC Nodes and How Do You Choose One for Production Apps?

Polymarket API Documentation: Which API Do You Actually Need?

Polymarket API: CLOB, Gamma, and the Onchain Layer Behind Them

Polygon Mainnet RPC: Chain Settings, Endpoint, and Connection Checks

Mainnet Faucet: What It Is and When You Actually Need One

Chain ID: What It Is and How to Verify It on Any EVM Network

UniCrypt (UNCX): What It Is and How to Build Around Its Contracts

What Is the Sepolia Testnet and How Do You Connect to It?

Free Crypto Faucets: Testnet Tokens, Safety, and RPC Setup

Alchemy Polygon RPC: What to Evaluate Before You Commit

Hyperliquid Testnet: RPC Endpoint, Faucet, and Chain Settings

Never Worry about Infrastructure Again

Supported Networks

Product

Company

Resources