GlossaryWeb ScrapingIntermediate

Request Throttling

Request throttling is deliberately slowing down how often a scraper sends requests so it stays under a site's limits. It helps avoid bans, server overload, and detection.

Last updated June 8, 2026

Definition

Request throttling is the practice of controlling the rate at which a client sends HTTP requests to a target server. In web scraping it means pacing requests so they resemble normal human or service traffic rather than a rapid automated flood.

How Throttling Works

Scrapers introduce deliberate delays between requests, cap concurrency, and sometimes add randomized jitter to avoid predictable patterns. This contrasts with server-side rate limiting, where the site enforces limits; throttling is the client voluntarily staying beneath them.

  • Fixed delays: A set pause, e.g. one request every 2s.
  • Randomized delays: Variable gaps to mimic human behavior.
  • Concurrency limits: Capping simultaneous connections.
  • Adaptive throttling: Slowing down when 429 responses appear.

Why It Matters for Scraping

Sending requests too fast is one of the quickest ways to get an IP banned or trigger bot detection. Combining throttling with IP rotation and proxies spreads load and sustains long scraping jobs. Respectful throttling also reduces strain on the target server, lowering the chance of being flagged as abusive.

Examples

1

Pausing 2-5 seconds between requests with random jitter to mimic a human

2

Backing off automatically after receiving HTTP 429 Too Many Requests

3

Limiting a crawler to 5 concurrent connections per domain

Common Use Cases

Avoiding IP bans during large scraping jobs
Preventing server overload on the target site
Staying under rate limits to reduce detection
Maintaining stable long-running crawls

Frequently Asked Questions

Rate limiting is enforced by the server to cap incoming requests. Throttling is the client voluntarily slowing itself down to stay below those limits and avoid bans.
It depends on the site, but randomized delays of a few seconds with limited concurrency are common. Adaptive backoff on 429 responses helps tune the rate dynamically.

Keep Learning

All terms

Rate Limiting

Rate limiting restricts how many requests a client can make in a given time, and it is one of the most common defenses scrapers must work around.

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IP Rotation

IP rotation is the practice of deliberately changing the source IP address your requests come from, spreading a large job across many addresses so no single one exceeds what a target tolerates.

Read definition

Web Scraping

Web scraping is the automated extraction of data from websites — fetching pages programmatically and parsing their content into structured data.

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Residential Proxy

A residential proxy routes your traffic through a real home internet connection, so websites see an ordinary ISP customer rather than a server in a data centre.

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