[Blog](https://scrapfly.io/blog) / [http](https://scrapfly.io/blog/tag/http) / [What is HTTP 406 Error? (Not Acceptable)](https://scrapfly.io/blog/posts/what-is-http-error-406-not-acceptable) # What is HTTP 406 Error? (Not Acceptable) by [Mostafa](https://scrapfly.io/blog/author/mostafa) Apr 01, 2026 5 min read [\#http](https://scrapfly.io/blog/tag/http) [ ](https://www.linkedin.com/sharing/share-offsite/?url=https%3A%2F%2Fscrapfly.io%2Fblog%2Fposts%2Fwhat-is-http-error-406-not-acceptable "Share on LinkedIn") When working on web scraping or automation, encountering HTTP errors can be frustrating, and HTTP error 406 is one that indicates a mismatch in the type of content being requested. In this article, we'll explore what HTTP 406 means, the common causes behind it, and whether it could be used as a blocking strategy. We'll also dive into how Scrapfly can help you bypass this error effectively. ## Key Takeaways Fix 406 not acceptable errors by configuring proper Accept headers (text/html, application/xhtml+xml), language headers (en-US,en;q=0.9), and encoding support (gzip, deflate, br) to successfully access web content. - HTTP 406 "Not Acceptable" occurs when server cannot deliver content matching the client's Accept- headers - Common causes include misconfigured Accept, Accept-Language, or Accept-Encoding headers in requests - Header configuration is crucial - use realistic browser headers like text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 - Language headers should match target region (e.g., en-US,en;q=0.9 for US English content) - Encoding support should include gzip, deflate, br to match modern browser capabilities - Content negotiation allows servers to return different formats based on client preferences - Anti-blocking strategy - 406 errors can sometimes be used as a blocking mechanism by websites - Scrapfly integration provides built-in header management and proxy rotation to avoid 406 blocks **Get web scraping tips in your inbox**Trusted by 100K+ developers and 30K+ enterprises. Unsubscribe anytime. ## What is HTTP Error 406? `406 Not Acceptable` error occurs when the server is unable to deliver a response in a format that matches the criteria defined by the client's `Accept-` headers. Essentially, the server understands the request, but it cannot find a response that fits the content types or formats that the client is willing to accept. ## What are HTTP 406 Error Causes? The most common cause of a 406 error is misconfigured `Accept-` headers. These headers tell the server what content types the client expects in the response, such as: - **Accept**: Specifies the expected media type, like `application/json` or `text/html`. - **Accept-Language**: Indicates the preferred languages for the response, e.g., `en-US`. - **Accept-Encoding**: Defines the compression formats that the client can handle, like `gzip` or `deflate`. If the server cannot provide a response that matches the specified `Accept-` headers, it will return a 406 status code. ### Practical Example Let's explore how to configure headers, specifically `Accept-` headers, in common tools like python's [httpx](https://www.python-httpx.org/) library, and [cURL](https://curl.se/). cURL Python (httpx) Javascript (fetch) Rust Go Ruby (typhoeus) PHP (guzzle) bash```bash curl -H "Accept: application/json" -H "Accept-Language: en-US" https://httpbin.dev/json ``` python```python import httpx url = "https://httpbin.dev/json" headers = { "Accept": "application/json", # Expecting JSON response "Accept-Language": "en-US", # Preferring English } response = httpx.get(url, headers=headers) print(response.status_code) print(response.text) ``` javascript```javascript const url = "https://httpbin.dev/json"; const headers = { "Accept": "application/json", // Expecting JSON response "Accept-Language": "en-US", // Preferring English }; fetch(url, { headers }) .then(response => response.json()) .then(data => console.log(data)) .catch(error => console.error('Error:', error)); ``` rust```rust use reqwest::header::{ACCEPT, ACCEPT_LANGUAGE}; use std::error::Error; #[tokio::main] async fn main() -> Result<(), Box> { let client = reqwest::Client::new(); let response = client .get("https://httpbin.dev/json") .header(ACCEPT, "application/json") .header(ACCEPT_LANGUAGE, "en-US") .send() .await?; println!("Status: {}", response.status()); println!("Body: {}", response.text().await?); Ok(()) } ``` go```go package main import ( "fmt" "io/ioutil" "net/http" ) func main() { client := &http.Client{} req, err := http.NewRequest("GET", "https://httpbin.dev/json", nil) if err != nil { fmt.Println("Error:", err) return } req.Header.Add("Accept", "application/json") req.Header.Add("Accept-Language", "en-US") resp, err := client.Do(req) if err != nil { fmt.Println("Error:", err) return } defer resp.Body.Close() body, _ := ioutil.ReadAll(resp.Body) fmt.Println("Status:", resp.Status) fmt.Println("Body:", string(body)) } ``` ruby```ruby require 'typhoeus' url = "https://httpbin.dev/json" response = Typhoeus.get(url, headers: { "Accept" => "application/json", # Expecting JSON response "Accept-Language" => "en-US" # Preferring English }) puts "Status: #{response.code}" puts "Body: #{response.body}" ``` php```php request('GET', $url, [ 'headers' => [ 'Accept' => 'application/json', // Expecting JSON response 'Accept-Language' => 'en-US', // Preferring English ] ]); echo "Status: " . $response->getStatusCode() . "\n"; echo "Body: " . $response->getBody(); ``` In both examples, the client is requesting a response in `application/json` format and prefers the response language in `en-US`. If the server cannot match these criteria, a 406 error might occur. To avoid 406 errors, ensure that your `Accept-` headers are set appropriately for the resource you're trying to access. ## 406 in Web Scraping When it comes to web scraping 406 status code is most commonly encountered when `Accept-` family headers are not provided or misconfigured. Most HTTP clients do no add default `Accept-` headers, so you need to set them manually. To verify what headers need take a look at how the website behaves in your web browser using [Browser Developer Tools](https://scrapfly.io/blog/answers/browser-developer-tools-in-web-scraping). Using the Network tab, you can see the exact `Accept` \[tref how-to-scrape-hidden-apis "headers your browser is sending" %\] and replicate them in your scrapers. Alternatively, there's a small possibility that 406 error is returned deliberately by the server to block web scraping and deceive the scraper in thinking there's a technical issue. If that's the case see our guide on [fortifying web scrapers against blocking](https://scrapfly.io/blog/posts/how-to-bypass-anti-bot-protection-when-web-scraping). ## FAQ How can I debug which Accept headers are causing a 406 error in my web scraper?Use [Browser Developer Tools](https://scrapfly.io/blog/answers/browser-developer-tools-in-web-scraping) to inspect the exact headers your browser sends when accessing the page successfully. Compare those with your scraper's headers to find the mismatch. ## Power Up with Scrapfly ScrapFly provides [web scraping](https://scrapfly.io/docs/scrape-api/getting-started), [screenshot](https://scrapfly.io/docs/screenshot-api/getting-started), and [extraction](https://scrapfly.io/docs/extraction-api/getting-started) APIs for data collection at scale. - [Anti-bot protection bypass](https://scrapfly.io/docs/scrape-api/anti-scraping-protection) - scrape web pages without blocking! - [Rotating residential proxies](https://scrapfly.io/docs/scrape-api/proxy) - prevent IP address and geographic blocks. - [JavaScript rendering](https://scrapfly.io/docs/scrape-api/javascript-rendering) - scrape dynamic web pages through cloud browsers. - [Full browser automation](https://scrapfly.io/docs/scrape-api/javascript-scenario) - control browsers to scroll, input and click on objects. - [Format conversion](https://scrapfly.io/docs/scrape-api/getting-started#api_param_format) - scrape as HTML, JSON, Text, or Markdown. - [Full screenshot customization](https://scrapfly.io/docs/screenshot-api/getting-started#api_param_capture) - scroll and capture exact areas. - [Comprehensive options](https://scrapfly.io/docs/screenshot-api/getting-started) - block banners, use dark mode, and more. - [LLM prompts](https://scrapfly.io/docs/extraction-api/llm-prompt) - extract data or ask questions using LLMs - [Extraction models](https://scrapfly.io/docs/extraction-api/automatic-ai) - automatically find objects like products, articles, jobs, and more. - [Extraction templates](https://scrapfly.io/docs/extraction-api/rules-and-template) - extract data using your own specification. - [Python](https://scrapfly.io/docs/sdk/python) and [Typescript](https://scrapfly.io/docs/sdk/typescript) SDKs, as well as [Scrapy](https://scrapfly.io/docs/sdk/scrapy) and [no-code tool integrations](https://scrapfly.io/docs/integration/getting-started). ## Summary HTTP 406 errors are caused by a mismatch between the `Accept-` headers sent by the client and the formats the server can deliver. While unlikely, these errors can sometimes be used as a blocking mechanism. Using Scrapfly's advanced tools, including proxy rotation and customizable requests, you can bypass 406 blocks and keep your web scraping running smoothly. Table of Contents Table of Contents- [Key Takeaways](#key-takeaways) - [What is HTTP Error 406?](#what-is-http-error-406) - [What are HTTP 406 Error Causes?](#what-are-http-406-error-causes) - [Practical Example](#practical-example) - [406 in Web Scraping](#406-in-web-scraping) - [FAQ](#faq) - [Power Up with Scrapfly](#power-up-with-scrapfly) - [Summary](#summary) Join the Newsletter Get monthly web scraping insights Scale Your Web Scraping Anti-bot bypass, browser rendering, and rotating proxies, all in one API. Start with 1,000 free credits. No credit card required 1,000 free API credits Anti-bot bypass included [Start Free](https://scrapfly.io/register) [View Docs](https://scrapfly.io/docs/onboarding) Not ready? 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