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No key, no signup. Point any client at the endpoint and call eth_chainId, you should get back 0x2105 (decimal 8453).

1234curl -X POST https://rpc.baseazul.dev \  -H 'content-type: application/json' \  -d '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}'# => {"jsonrpc":"2.0","id":1,"result":"0x2105"}

12345678910111213import { createPublicClient, http, fallback } from 'viem';import { base } from 'viem/chains';​// Azul first; transparently falls back to the public RPC if it ever blips.export const client = createPublicClient({  chain: base,  transport: fallback(    [http('https://rpc.baseazul.dev'), http('https://mainnet.base.org')],    { rank: true }, // poll latency, keep the fastest path on top  ),});​const tip = await client.getBlockNumber(); // => latest Base block (bigint)

12345import { JsonRpcProvider } from 'ethers';​const provider = new JsonRpcProvider('https://rpc.baseazul.dev');const tip = await provider.getBlockNumber();// => latest Base block height, e.g. 21000000 (number)

123456789import { createConfig, http } from 'wagmi';import { base } from 'wagmi/chains';​export const config = createConfig({  chains: [base],  transports: {    [base.id]: http('https://rpc.baseazul.dev'),  },});

12345from web3 import Web3​w3 = Web3(Web3.HTTPProvider("https://rpc.baseazul.dev"))tip = w3.eth.block_number# => latest Base block height, e.g. 21000000

1234curl -X POST https://rpc.baseazul.dev \  -H 'content-type: application/json' \  -d '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}'# => {"jsonrpc":"2.0","id":1,"result":"0x2105"}

12345678910111213import { createPublicClient, http, fallback } from 'viem';import { base } from 'viem/chains';​// Azul first; transparently falls back to the public RPC if it ever blips.export const client = createPublicClient({  chain: base,  transport: fallback(    [http('https://rpc.baseazul.dev'), http('https://mainnet.base.org')],    { rank: true }, // poll latency, keep the fastest path on top  ),});​const tip = await client.getBlockNumber(); // => latest Base block (bigint)

12345import { JsonRpcProvider } from 'ethers';​const provider = new JsonRpcProvider('https://rpc.baseazul.dev');const tip = await provider.getBlockNumber();// => latest Base block height, e.g. 21000000 (number)

123456789import { createConfig, http } from 'wagmi';import { base } from 'wagmi/chains';​export const config = createConfig({  chains: [base],  transports: {    [base.id]: http('https://rpc.baseazul.dev'),  },});

12345from web3 import Web3​w3 = Web3(Web3.HTTPProvider("https://rpc.baseazul.dev"))tip = w3.eth.block_number# => latest Base block height, e.g. 21000000

One HTTPS URL serves all standard JSON-RPC methods. Public traffic does not require an API key. Privileged keys exist for higher limits and access to restricted namespaces.

The endpoint is standard JSON-RPC 2.0. Content-Type must be application/json. Body is a single request object or an array (batch). Responses are gzip/zstd compressed when the client advertises support.

All standard eth_*, net_*, and web3_* methods are available on the public path. Restricted namespaces are blocked unless you authenticate with an API key.

Need debug_* or trace_* for production analytics? Request an API key.

Per-IP limits on anonymous traffic. API-key holders bypass all of these.

JSON-RPC errors follow standard codes. HTTP-level errors come back as raw responses.

Server-side latency from us-east-1. /status owns the live proof; these are the published reference values.

Batch up to 50 requests in a single POST. Useful for fan-out reads (multicall warmup, ENS resolution, parallel eth_call). One TLS handshake, lower tail latency.

12345[  {"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1},  {"jsonrpc":"2.0","method":"eth_getBalance","params":["0xabc…","latest"],"id":2},  {"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":3}]

12345[  {"jsonrpc":"2.0","id":1,"result":"0x1414958"},  {"jsonrpc":"2.0","id":2,"result":"0x2386f26fc10000"},  {"jsonrpc":"2.0","id":3,"result":"0x2105"}]

Max range is 5,000 blocks per call. Wider ranges return -32602. Page through history by chunking the range and parallelizing requests, see Page through eth_getLogs.

One key raises every cap on this page and opens restricted namespaces (debug_*, trace_*). Tell us your workload and we’ll set you up, a free key for normal development, no strings. (WebSocket subscriptions and streaming feeds are Edge early access; if you’re a fill-sensitive desk, see Edge below.)

Authenticate

Once you have a key, present it in the X-API-Key request header (or ?api_key= on the WebSocket URL):

1234curl -s https://rpc.baseazul.dev \  -H 'content-type: application/json' \  -H 'X-API-Key: YOUR_KEY' \  --data '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}'

Azul is single-region. For production, pair it with a paid provider. viem has a built-in fallback transport: the first URL wins, and the second takes over on error or timeout.

12345678910import { createPublicClient, http, fallback } from 'viem';import { base } from 'viem/chains';​export const client = createPublicClient({  chain: base,  transport: fallback([    http('https://rpc.baseazul.dev'),                  // Azul, primary, fast, no logging    http('https://mainnet.base.org'),       // Coinbase default, last resort  ], { retryCount: 1, retryDelay: 100 }),});

Don’t poll eth_blockNumber in a tight loop. WebSocket subscriptions are Edge early access. If your workload depends on live tip-follow, request a key and we’ll bring you in. Here is the shape it takes:

1234567891011import { createPublicClient, webSocket } from 'viem';import { base } from 'viem/chains';​const client = createPublicClient({  chain: base,  transport: webSocket('wss://rpc.baseazul.dev/ws?api_key=YOUR_KEY'),});​const unwatch = client.watchBlockNumber({  onBlockNumber: (n) => console.log('new tip', n),});

Chunk wide ranges into 5,000-block windows and parallelize. Concurrent batches are accepted up to your per-IP cap.

123456789async function getLogsRange(client, address, fromBlock, toBlock) {  const PAGE = 5000;  const tasks = [];  for (let start = fromBlock; start <= toBlock; start += PAGE) {    const end = Math.min(start + PAGE - 1, toBlock);    tasks.push(client.getLogs({ address, fromBlock: start, toBlock: end }));  }  return (await Promise.all(tasks)).flat();}

The endpoint sets Access-Control-Allow-Origin: *. Browser fetch works from any origin. Preflight (OPTIONS) responds with 204 and a 24-hour max-age.

Azul picks a propagation path to the Base sequencer for every request, chosen for low latency and reliable inclusion. Reads and writes use separate paths, each tuned to its own workload.

The result is fast inclusion and failover that holds up at one transaction or a thousand.

Sandwich attacks skim value from your trades. They need a window: a pending interval during which a searcher can see your transaction and wedge their own ahead of it.

Azul minimizes that window. Transactions are not parked anywhere inspectable for longer than necessary; the routing prioritizes getting them included over making them visible.

The RPC path retains nothing per-request, no IPs, request bodies, response bodies, or cross-request identifiers. The only counter is anonymous aggregate bytes/day for the egress cap, which resets daily and isn’t attributed to any IP or request. Full posture statement: /privacy.