RPC / Node·Bitcoin · EVM · Solana · Multi-chain
NOWNodes
RPC and Blockbook explorer APIs for 100+ chains with strong UTXO and Bitcoin-family coverage, single-header authentication, and WebSocket support.
- 01Bitcoin and UTXO chain RPC
- 02Blockbook explorer API
- 03100+ chain breadth
- 04WebSocket subscriptions
- 05single-API-key multi-chain access
- pnpm add viem
| Variable | Scope | Description |
|---|---|---|
| NOWNODES_API_KEY | Server | NOWNodes API key. Sent as the `api-key` request header. Server-side only. |
| NOWNODES_RPC_URL | Server | Full NOWNodes RPC URL, e.g. `https://eth.nownodes.io` for Ethereum, `https://btc.nownodes.io` for Bitcoin. Server-side only. |
Use NOWNodes as the JSON-RPC transport. Endpoint pattern is `https://<chain>.nownodes.io` (e.g. `eth`, `btc`, `bsc`, `matic`, `sol`, `doge`, `ltc`, `trx`). Authentication is the `api-key: ${NOWNODES_API_KEY}` request header — NOT a URL path or query param. Wire into `viem` via a transport that adds the header: `http(process.env.NOWNODES_RPC_URL, { fetchOptions: { headers: { 'api-key': process.env.NOWNODES_API_KEY! } } })`. For Bitcoin-family chains, NOWNodes also exposes Blockbook at `https://<chain>book.nownodes.io` with REST endpoints like `/api/v2/address/<addr>` for UTXO queries. WebSockets are available on `wss://<chain>.nownodes.io/wss/<API_KEY>`. The same key works across all chains.
- ⚑Authentication is via the `api-key` header (NOT `Authorization: Bearer ...`, NOT a URL path) — proxies that don't forward custom headers break NOWNodes calls.
- ⚑WebSocket auth puts the API key IN the URL path (`/wss/<KEY>`) instead of a header — that URL is a credential and must never be shipped client-side.
- ⚑Free public endpoints (no key) exist for ETH/BSC/BTC at `nownodes.io/public-endpoints` but have aggressive rate limits and no SLA — production must use an authenticated key.
- ⚑Free tier has a daily request cap; Blockbook calls and `eth_getLogs` over wide ranges count the same as `eth_blockNumber` and exhaust the quota fast.
- ⚑Archive-mode access on EVM is gated behind paid plans; historical state on free/starter tiers is limited.
- ⚑UTXO node eviction: large `getrawtransaction` or address-history calls on shared Bitcoin nodes can timeout under load — use Blockbook instead of raw RPC for address scans.
- ⚑Regional latency: NOWNodes routes geographically but does not let you pin a region — for latency-critical paths, benchmark or pay for a dedicated node.