Micro Requester

Professional HTTP client for microservice-to-microservice communication in Node.js and NestJS projects.

Focused • Reliable • Small Surface Area • Production Ready

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Why micro-requester?

micro-requester is intentionally focused on one job: reliable HTTP calls between services.

• One primary API: createClient()
• Preserves upstream 4xx payloads (like 409 Conflict) instead of masking them
• Normalizes transport failures into predictable gateway-style errors
• Built-in timeout and retry control with sensible defaults
• Works in plain Node.js and NestJS

If your project has custom middleware, tracing, or request context strategy, keep that in your app and pass getReqId.

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Installation

npm install micro-requester

Requirements: Node.js 18+

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Quick Start

import { createClient } from 'micro-requester';

const users = createClient({
  service: 'users-service',
  base: process.env.USERS_SERVICE_HTTP_URL || 'http://localhost:3001',
  timeoutMs: 5000,
  retries: 2,
  getReqId: () => requestContext.getStore()?.requestId, // optional
});

const user = await users.get('/users/1');

const created = await users.post('/users', {
  email: 'alice@example.com',
  name: 'Alice',
});

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API Reference

createClient(options)

Creates a reusable client for one upstream service.

type ClientOptions = {
  service: string;
  base: string;
  timeoutMs?: number;
  retries?: number;
  retryStatuses?: number[];
  headers?: Record<string, string>;
  getReqId?: () => string | undefined;
};

Parameter details:

• service: service label used in mapped errors
• base: upstream base URL
• timeoutMs: default timeout per request (default 5000)
• retries: default retry count (default 2)
• retryStatuses: status codes considered retryable for idempotent methods (default [502, 503, 504])
• headers: default headers merged into every request
• getReqId: optional request ID resolver; falls back to generated UUID

Client

type Client = {
  req<T>(input: ReqInput): Promise<T>;
  get<T>(path: string, opts?: Partial<ReqInput>): Promise<T>;
  post<T>(path: string, body?: unknown, opts?: Partial<ReqInput>): Promise<T>;
  put<T>(path: string, body?: unknown, opts?: Partial<ReqInput>): Promise<T>;
  patch<T>(path: string, body?: unknown, opts?: Partial<ReqInput>): Promise<T>;
  delete<T>(path: string, opts?: Partial<ReqInput>): Promise<T>;
};

ReqInput

type ReqInput = {
  method: 'GET' | 'POST' | 'PUT' | 'PATCH' | 'DELETE' | 'HEAD' | 'OPTIONS';
  path: string;
  body?: unknown;
  query?: Record<string, string | number | boolean | undefined>;
  headers?: Record<string, string>;
  timeoutMs?: number;
  retry?: false | number;
};

Notes:

• If body is an object, it is JSON-stringified automatically.
• If content-type is missing for object body, application/json is set.
• x-request-id is always attached to outgoing requests.
• req() supports all methods in ReqInput, including HEAD and OPTIONS.

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Error Behavior

Upstream responses

• 4xx responses are passed through with original body/message
• 5xx responses are normalized to 502 Bad Gateway

Transport failures

• ECONNREFUSED -> 503 Service Unavailable
• timeout/abort/UND_ERR* -> 504 Gateway Timeout
• other transport failures -> 502 Bad Gateway

This behavior is designed to prevent business errors (for example duplicate email 409) from being hidden by generic transport messages.

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Retry Model

Retries are conservative by default:

• Retryable methods: GET, HEAD, OPTIONS
• Retryable statuses: 502, 503, 504
• Retryable transport errors: ECONNREFUSED, ETIMEDOUT, ENOTFOUND, UND_ERR_CONNECT_TIMEOUT, UND_ERR_SOCKET

Backoff:

• Exponential: 100 * 2^attempt
• Jitter: up to 50ms
• Max delay: 1500ms

Override per request:

await users.get('/health', { retry: false });
await users.get('/health', { retry: 1 });

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NestJS Integration Example

import { Injectable } from '@nestjs/common';
import { createClient } from 'micro-requester';
import { requestContext } from './request-context.middleware';

@Injectable()
export class UsersClient {
  private readonly client = createClient({
    service: 'users-service',
    base: process.env.USERS_SERVICE_HTTP_URL || 'http://localhost:3001',
    timeoutMs: 5000,
    retries: 2,
    getReqId: () => requestContext.getStore()?.requestId,
  });

  getUser(id: string) {
    return this.client.get(`/users/${id}`);
  }

  createUser(body: unknown) {
    return this.client.post('/users', body);
  }
}

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Design Philosophy

• Keep package concerns inside HTTP execution and error mapping
• Keep project concerns (middleware/context/observability) inside your app
• Preserve upstream business errors by default

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License

MIT