@hyperttp/transport-undici

A high-performance network transport layer for the hyperttp HTTP client, built directly on top of the low-level Undici Dispatch API. Engineered specifically for Node.js environments with extreme throughput (RPS) requirements and ultra-low latency demands.

✨ Features

• Undici Dispatch API: Bypasses the overhead of the standard fetch API and Node.js streams by collecting chunk buffers directly via low-level pool lifecycle events.
• Ultra-Stable p99 Latency: Drastically reduces Garbage Collector (GC) pressure by optimizing AbortSignal lifecycle management and minimizing closure allocations per request.
• Native Policy Integration: End-to-end, out-of-the-box support for hyperttp core mechanisms including Retry Policies, smart Redirect Policies, and custom network timeouts.
• Safe Event Loop: Isolated abort logic guarantees that connection teardowns never yield unhandled promise rejections or dangling timer macro-tasks.

📊 Performance (Node.js v24)

Benchmark: 20,000 requests · Concurrency: 200 · Duration: 60s · Target: local JSON endpoint

Node.js v24.16.0 — UndiciTransport

• OS: linux 7.1.3-zen2-1-zen
• CPU: Intel(R) Core(TM) i5-8600K CPU @ 3.60GHz

| Rank | Client | RPS | Avg | p50 | p90 | p99 | Errors | | :--: | :------------- | -----: | -------: | -------: | -------: | -------: | -----: | | 🥇 1 | undici | 15.98K | 12.47 ms | 12.08 ms | 14.17 ms | 18.80 ms | 0 | | 🥈 2 | @hyperttp/core | 13.08K | 15.11 ms | 13.98 ms | 17.03 ms | 23.32 ms | 0 | | 🥉 3 | bun-fetch | 8.56K | 23.25 ms | 21.78 ms | 29.81 ms | 34.75 ms | 0 | | 4 | axios | 4.74K | 42.08 ms | 40.66 ms | 46.62 ms | 56.00 ms | 0 |

📦 Installation

Since this transport is optional, you need to add it to your project manually:

bun add @hyperttp/transport-undici
# or
npm install @hyperttp/transport-undici

🚀 Usage

Basic Initialization with Core

import { HyperClient } from "@hyperttp/core";
import { UndiciTransport } from "@hyperttp/transport-undici";

const client = new HyperClient({
  baseUrl: "https://api.example.com",
  transport: new UndiciTransport({
    network: {
      maxConcurrent: 500, // Maximum concurrent sockets
      pipelining: 8, // Request pipelining depth per socket
      keepAliveTimeout: 30000, // Socket keep-alive timeout in ms
    },
    retry: {
      maxRetries: 3,
      retryStatuses: [502, 503, 504],
    },
  }),
});

const response = await client.request({
  url: "/v1/users",
  method: "GET",
});

const users = await response.json();

Using an External (Custom) Dispatcher

If your application already manages a global undici Agent or Pool (e.g., for proxy configurations or Unix domain sockets), you can inject it directly:

import { Pool } from "undici";
import { UndiciTransport } from "@hyperttp/transport-undici";

const customPool = new Pool("http://localhost:3000", {
  connections: 100,
  connect: { rejectUnauthorized: false },
});

const transport = new UndiciTransport({
  dispatcher: customPool, // Injecting the existing instance
});

⚠️ Note: When a dispatcher is provided from an external context, transport.close() and transport.destroy() calls within hyperttp are ignored to prevent side effects in the parent environment. Managing the pool lifecycle remains the responsibility of your application architecture.

🛠 Abort & Timeout Architecture

The transport utilizes an atomic combineSignal utility that couples the user's external AbortSignal with an internal task-limiting timer:

1. Dispatch Handler Level: During the onResponseData streaming phase, if the abort signal gets triggered, the underlying socket is immediately terminated via controller.abort().
2. Error Policy Level: Low-level header timeouts (UND_ERR_HEADERS_TIMEOUT) and body timeouts (UND_ERR_BODY_TIMEOUT) are gracefully normalized into standard AbortError instances while preserving the original cause for diagnostics.

📄 License

MIT