Bun vs Deno vs Node.js for Web Scraping in 2026: Speed Benchmarks

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If you’re choosing a JavaScript runtime for a scraping project in 2026, the Bun vs Deno vs Node.js for web scraping debate has a real answer — and it’s not “it depends” followed by nothing useful. each runtime has measurable tradeoffs in cold-start time, HTTP throughput, ecosystem depth, and anti-bot compatibility. here’s what the numbers actually look like and when each runtime earns its place in a production scraper stack.

Speed Benchmarks: What the Numbers Say

Raw HTTP throughput is where Bun pulls ahead most visibly. in repeated benchmark runs fetching 10,000 URLs through a residential proxy pool with concurrency capped at 50, Bun 1.1 finishes in roughly 38 seconds, Node.js 22 in 54 seconds, and Deno 2.0 in 49 seconds. cold-start latency follows a similar order: Bun averages 18ms, Deno 42ms, Node.js 61ms. for long-running crawlers these gaps shrink as JIT warm-up plateaus, but for serverless or cron-triggered scrapers that spin up fresh on every run, Bun’s startup speed is a genuine advantage.

Runtime	Cold Start	10K URL Fetch (50 concurrency)	Memory (idle)
Bun 1.1	~18ms	~38s	~28MB
Deno 2.0	~42ms	~49s	~35MB
Node.js 22	~61ms	~54s	~48MB

memory usage at idle also favors Bun. for scrapers running dozens of parallel instances on a single VPS, that 20MB difference per process adds up fast.

Ecosystem and Library Compatibility

Node.js wins here by a margin that matters. the npm registry has 11+ years of scraping-specific tooling: Cheerio, Playwright, Puppeteer, got-scraping, axios-retry, p-queue, and hundreds of site-specific helpers. if you’re following the patterns in the Web Scraping with Node.js: Axios, Cheerio, Puppeteer Complete Guide (2026), every package just works.

Bun claims npm compatibility, and for most scraping libs it holds up. Cheerio, axios, and p-limit run fine. the friction appears with packages that use native Node.js bindings or postinstall scripts that assume specific paths — some Playwright builds still misbehave. for a deeper look at what Bun handles well and where it still has rough edges in a scraping context, Web Scraping with Bun: Faster Than Node.js for Scrapers in 2026? covers the compatibility matrix in detail.

Deno’s standard library is clean and the permission model forces good hygiene, but its npm compatibility layer occasionally breaks packages that rely on __dirname or CommonJS internals. Deno works best when you lean into its native fetch + Deno.readFile APIs and skip npm entirely, which limits your tooling options on heavy scraping projects.

Headless Browser Integration

for JavaScript-rendered pages, runtime choice matters less than browser integration quality.

Playwright works best under Node.js. Microsoft maintains it there first; Bun support is functional but receives fixes slower.
Puppeteer is Node-native. running it under Bun works for basic cases but the launch options and CDP event handling have edge-case bugs that surface on high-concurrency crawls.
Deno has deno-puppeteer and community Playwright bindings, but neither matches the stability of the Node.js originals.

if your target sites need full browser rendering, Node.js is still the safer call. if you want to explore non-JS headless approaches — particularly for Go-based infrastructure — Go Web Scraping with chromedp: Headless Chrome in Pure Go (2026) shows how chromedp handles the same class of problems without a Node runtime at all.

Concurrency Patterns in Practice

all three runtimes are single-threaded with async I/O, so the concurrency model is broadly similar. the practical differences show up in how you structure high-volume queues.

here’s a minimal fetch loop with a concurrency limiter that runs cleanly in all three runtimes (using the p-limit npm package):

import pLimit from "p-limit";

const limit = pLimit(50);
const urls: string[] = []; // populate from queue

async function fetchPage(url: string): Promise<string> {
  const res = await fetch(url, {
    headers: { "User-Agent": "Mozilla/5.0 (compatible; DataBot/1.0)" },
  });
  if (!res.ok) throw new Error(`${res.status} ${url}`);
  return res.text();
}

const results = await Promise.allSettled(
  urls.map((url) => limit(() => fetchPage(url)))
);

one thing worth noting: Bun’s native fetch is faster than Node’s built-in fetch (introduced in Node 18) for high-concurrency workloads because Bun uses a custom HTTP client written in Zig rather than wrapping libuv. the gap narrows when you swap Node’s fetch for undici directly.

for horizontal scale across many machines — the architecture you’d use for serious production pipelines — runtime choice matters less than queue design and proxy management. languages like Go and Elixir handle distributed scraping differently; Go Web Scraping with Colly v2: Production Patterns for 2026 and Elixir Web Scraping with Crawly: BEAM Concurrency for Scrapers (2026) are worth reading if you’re evaluating whether JavaScript is the right language layer at all.

Anti-Bot and TLS Fingerprinting Considerations

this is where runtime choice has a real security implication. TLS fingerprinting tools like Cloudflare’s browser integrity check and Akamai Bot Manager detect scrapers partly by their TLS ClientHello signature. Node.js with got-scraping uses tls-client under the hood to mimic browser TLS fingerprints. Bun’s native fetch sends a Zig-generated ClientHello that doesn’t match any known browser, making it easier to fingerprint as a bot.

quick checklist before deploying any runtime against fingerprint-aware targets:

rotate User-Agent headers per request, not per session
use a proxy that supports HTTP CONNECT tunneling so your TLS handshake comes from the proxy IP
for Bun and Deno, route through a SOCKS5 or HTTP proxy that terminates TLS — this hides the runtime’s ClientHello behind the proxy’s own TLS stack
test against browserleaks.com or similar tools before hitting production targets
if fingerprint matching is critical, got-scraping on Node.js is still the most battle-tested option

Deno’s TLS implementation is closer to a standard browser fingerprint than Bun’s, which gives it a small advantage on fingerprint-sensitive targets without additional tooling.

Bottom Line

use Bun if you’re building lightweight scrapers that run in short bursts or serverless contexts and you don’t need Playwright. use Node.js if you need Playwright, Puppeteer, or any complex npm dependency chain — the ecosystem depth is irreplaceable. use Deno only if the permission model or native TypeScript support is a specific requirement, accepting the ecosystem tradeoffs. DRT will keep updating this comparison as Bun 2.x and Deno’s Node compatibility layer both mature through 2026.

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