@coxy/axios-pool

@coxy/axios-pool is a small but powerful library for managing multiple Axios instances with built-in failover, load balancing, and parallel request capabilities.

Features

• Failover handling: Automatically retries requests with the next instance if the first one fails.
• Parallel request mode: Send requests to all instances at once and use the fastest valid response.
• Custom response validation: Plug in your logic to verify responses.
• RPC support: Send JSON-RPC 2.0 requests easily across multiple nodes.

Installation

npm install @coxy/axios-pool

Quick Start

Basic Usage

import { createAxiosPool } from '@coxy/axios-pool'

const pool = createAxiosPool(
  { sendAll: true },
  'https://node1.example.com',
  'https://node2.example.com'
)

const response = await pool.get('/health')

Usage with Failover (sendAll: false)

import { createAxiosPool } from '@coxy/axios-pool'

const pool = createAxiosPool(
  { sendAll: false, timeout: 1000 },
  'https://primary-node.example.com',
  'https://backup-node.example.com'
)

const response = await pool.post('/data', { key: 'value' })

Validating Responses

import { createAxiosPool } from '@coxy/axios-pool'

const pool = createAxiosPool(
  {
    sendAll: true,
    validateResponse: (data) => {
      if (!data || typeof data !== 'object' || data.status !== 'ok') {
        throw new Error('Invalid response')
      }
    },
  },
  'https://node1.example.com',
  'https://node2.example.com'
)

const response = await pool.get('/check')

JSON-RPC over Axios Pool

import { RpcAxiosPool } from '@coxy/axios-pool'

const rpcPool = new RpcAxiosPool([
  'https://rpc1.example.com',
  'https://rpc2.example.com'
])

const blockNumber = await rpcPool.request('eth_blockNumber')

API

createAxiosPool(initialOptions?: AxiosPoolConfig, ...configs: (AxiosInstance | string)[]): AxiosInstance

Creates a dynamic Axios proxy with failover and/or parallel strategies.

AxiosPoolConfig Options:

• sendAll?: boolean — If true, sends requests to all instances and returns the first valid one. Defaults to true.
• timeout?: number — Delay in milliseconds before retrying the next instance (when sendAll: false). Defaults to 0.
• validateResponse?: (data: any) => void — Optional function to validate the returned response.

RpcAxiosPool

Wrapper for sending JSON-RPC 2.0 requests using an Axios pool.

Constructor:

new RpcAxiosPool(nodes: (AxiosInstance | string)[], options?: AxiosPoolConfig)

Methods:

• request(method: string, ...params: any[]): Promise<AxiosResponse> — Sends a JSON-RPC 2.0 request.

License

MIT

Fun fact: Axios itself is named after the Greek word "ἄξιος" (áxios), meaning "worthy" — reflecting its goal to be a worthy HTTP client!