Question 1

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 2

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 3

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 4

Hyperliquid Docs: Where to Start for API and RPC Access

Accepted Answer

Hyperliquid's official documentation is the source of truth for the chain's architecture, API surfaces, and SDKs. It covers HyperCore (the fully onchain order book layer) and HyperEVM (the Ethereum-compatible smart contract layer), which share one consensus and one state. If you are building on Hyperliquid, you will likely need to read the docs for API semantics and then choose how to connect: public endpoints, a managed RPC provider, or your own node.

This page is a developer-oriented map of the Hyperliquid docs. It explains what each documentation area is for, how the API surfaces differ, and where RPC infrastructure fits into a working setup. It does not replace the official docs; it helps you decide what to read first and what to configure next.

OnFinality provides RPC API and dedicated node infrastructure for supported networks. If Hyperliquid is part of your stack, check the supported networks page and RPC pricing to see what is available before you finalize your connection strategy.

Question 5

Optimism RPC Nodes and API: How Do You Run and Scale Them?

Accepted Answer

Optimism RPC nodes expose the OP Mainnet JSON-RPC API, and running them reliably means understanding archive data, rate limits, and the difference between shared endpoints and dedicated infrastructure. This article walks through endpoint configuration, workload fit, and operational checks so you can decide whether to self-host, use a shared RPC API, or rent dedicated nodes. It also covers common failure modes and how to validate a provider before moving production traffic.

Question 6

Arbitrum API Overview: RPC Endpoints, Chain Settings, and Production Setup

Accepted Answer

The Arbitrum API is a JSON-RPC interface that lets your application read state and submit transactions on Arbitrum One (chain ID 42161) and Arbitrum Sepolia (chain ID 421614). You connect by pointing an HTTP or WebSocket client at an Arbitrum RPC endpoint and calling standard Ethereum-compatible methods such as eth_call, eth_getLogs, and eth_sendRawTransaction. This overview covers the chain settings you need, how to make your first request, which methods matter for production, and how to choose between public, shared, and dedicated node infrastructure.

Question 7

Bitcoin RPC Endpoints & API Access: How Do You Connect to the Bitcoin Network?

Accepted Answer

Bitcoin does not use EVM-style JSON-RPC. Instead, node software like Bitcoin Core exposes a JSON-RPC interface for wallet, blockchain, and mempool operations, while most applications rely on indexed APIs or managed node providers for address lookups and transaction data. This article explains the available access patterns, the chain settings you need, and how to decide between public endpoints, managed RPC APIs, and dedicated Bitcoin nodes. OnFinality provides managed RPC API and dedicated node infrastructure for supported networks, including Bitcoin, so you can connect without running your own full node.

Question 8

What do developers mean by a free Solana RPC, and when is it enough?

Accepted Answer

A free Solana RPC is typically a shared public endpoint or a free tier from a provider. These are useful for learning, prototyping, and low-volume scripts, but they come with shared rate limits, variable latency, and limited access to historical data or WebSocket subscriptions. Reddit threads often ask where to find one and whether it can handle real workloads.

For production apps, the better path is a managed RPC API with clear limits or a dedicated node. OnFinality offers both, with public endpoints for quick tests and dedicated infrastructure for consistent performance. Check supported networks and pricing to match your workload.

Question 9

How do I add the Polygon network to MetaMask?

Accepted Answer

Adding Polygon to MetaMask takes about a minute: open the network selector, choose Add network, and enter the Polygon mainnet chain settings (chain ID 137, POL gas token, and an RPC endpoint). The tricky part is usually the RPC URL, because public endpoints rate-limit and can fail during busy periods.

This page gives you the exact Polygon mainnet and Amoy testnet settings, a wallet configuration you can paste, and a short guide to choosing an RPC endpoint that stays responsive once you move past casual testing.

Question 10

How do I connect to the Bittensor network for RPC access?

Accepted Answer

The Bittensor network is a decentralized machine learning protocol where subnets coordinate AI models and miners. For developers, the practical entry point is the Finney mainnet, which exposes a Substrate-based JSON-RPC interface for reading chain state, submitting extrinsics, and subscribing to events. This article explains how to connect, what to check before you build, and when a managed RPC or dedicated node makes sense. OnFinality provides RPC API and dedicated node infrastructure for Bittensor Finney, so you can focus on subnet logic instead of node operations.

Question 11

How do I add a BNB Chain RPC to MetaMask?

Accepted Answer

Adding BNB Smart Chain to MetaMask takes one network form: chain ID 56, the BNB Chain RPC URL you want to use, BNB as the currency symbol, and https://bscscan.com as the explorer. The part that actually affects your app is which RPC URL you paste in, because a public endpoint and a managed or dedicated endpoint behave very differently under load.

This page covers the exact chain settings for BNB Smart Chain mainnet and testnet, how to add them in MetaMask, how to verify the connection with curl and ethers, and when a shared public endpoint is enough versus when you should move to managed or dedicated BNB Chain infrastructure.

Question 12

How do you use a Chainlist-style directory to find supported RPC networks and endpoints?

Accepted Answer

Chainlist-style directories exist to solve one problem: mapping a chain ID to a working RPC endpoint so wallets and dApps can connect without guesswork. This article explains how those directories are structured, how to read the network metadata they expose, and how to verify an endpoint before you ship it to production.

It also covers where public directory endpoints stop being enough, what to check when a listed endpoint fails, and how a managed RPC API or dedicated node fits when you need predictable behavior across many chains.

API Service

Dedicated Nodes

Enterprise Nodes

Indexer Services

Network Prototyping Tools

Staking & Validators

AI Agent

RPC documentation entries

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

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

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

Hyperliquid Docs: Where to Start for API and RPC Access

Optimism RPC Nodes and API: How Do You Run and Scale Them?

Arbitrum API Overview: RPC Endpoints, Chain Settings, and Production Setup

Bitcoin RPC Endpoints & API Access: How Do You Connect to the Bitcoin Network?

What do developers mean by a free Solana RPC, and when is it enough?

How do I add the Polygon network to MetaMask?

How do I connect to the Bittensor network for RPC access?

How do I add a BNB Chain RPC to MetaMask?

How do you use a Chainlist-style directory to find supported RPC networks and endpoints?

Never Worry about Infrastructure Again

Supported Networks

Product

Company

Resources

Network RPC RPC Assistant

RPC documentation entries

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

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

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

Hyperliquid Docs: Where to Start for API and RPC Access

Optimism RPC Nodes and API: How Do You Run and Scale Them?

Arbitrum API Overview: RPC Endpoints, Chain Settings, and Production Setup

Bitcoin RPC Endpoints & API Access: How Do You Connect to the Bitcoin Network?

What do developers mean by a free Solana RPC, and when is it enough?

How do I add the Polygon network to MetaMask?

How do I connect to the Bittensor network for RPC access?

How do I add a BNB Chain RPC to MetaMask?

How do you use a Chainlist-style directory to find supported RPC networks and endpoints?

Never Worry about Infrastructure Again

Supported Networks

Product

Company

Resources