Accept-Encoding Header Analyzer
Paste any Accept-Encoding request header and instantly decode which compression algorithms the client supports, their preference order (q-values), and the optimal Content-Encoding to serve in your response. The accept-encoding header analyzer supports GZIP, Brotli, Zstandard, DEFLATE, and identity — with browser compatibility details and a suggested Nginx config. Runs entirely in your browser with no signup required.
Accept-Encoding Header Analyzer
Paste an Accept-Encoding request header and instantly decode which compression algorithms the client supports, their preference order (q-values), browser compatibility, and the optimal encoding to serve. Runs entirely in your browser — no signup required.
Load an example:
Paste the full header line (e.g. Accept-Encoding: gzip, deflate, br) or just the value (e.g. gzip, deflate, br). Press Cmd/Ctrl+Enter to analyze.
Why Use Our Accept-Encoding Header Analyzer?
Instant Accept-Encoding Decoding
Decode any Accept-Encoding header instantly in your browser — no server round-trip, no waiting. The accept-encoding header analyzer parses q-values, detects supported encodings, and recommends the optimal Content-Encoding to serve in milliseconds.
Secure Accept-Encoding Analyzer Online
Your header data never leaves your device. The accept-encoding header analyzer runs entirely in your browser — no server uploads, no data transmission, 100% private. Safe for analyzing headers from production traffic logs and internal APIs.
Full Q-Value and Encoding Support Detection
The accept-encoding header analyzer decodes all standard encodings — GZIP, Brotli (br), Zstandard (zstd), DEFLATE, and identity — with q-value preference bars, browser compatibility details, and a ready-to-use Nginx configuration snippet.
100% Free Forever
The accept-encoding header analyzer is completely free with no signup, no premium tier, no limits, and no ads. Analyze unlimited Accept-Encoding headers at zero cost, forever.
Common Use Cases for Accept-Encoding Header Analyzer
Debugging HTTP Compression Negotiation
When a server is not serving compressed responses, paste the Accept-Encoding header from the browser DevTools Network tab into the accept-encoding header analyzer to verify the client actually supports GZIP or Brotli — and confirm the server is reading the header correctly.
Diagnosing Garbled API Responses
If an API client receives garbled binary data instead of JSON, it may be receiving a compressed response it cannot decompress. Use the accept-encoding header analyzer to check whether the client's Accept-Encoding header includes the encoding the server is sending.
Server Configuration Validation
Before deploying a new Nginx or Apache compression configuration, use the accept-encoding header analyzer to verify that your target clients (browsers, mobile apps, API consumers) actually support the encoding you plan to serve — and get a ready-to-use config snippet.
API Client Compression Audit
Audit the Accept-Encoding headers sent by your API clients — mobile apps, SDKs, and third-party integrations. The accept-encoding header analyzer shows exactly which encodings each client supports, helping you decide whether to enable Brotli or Zstandard for your API endpoints.
CDN and Proxy Compression Verification
CDNs and reverse proxies sometimes strip or modify Accept-Encoding headers before forwarding requests to origin servers. Use the accept-encoding header analyzer to compare headers at different points in your request pipeline and identify where compression negotiation breaks down.
Browser Compatibility Research
Research which compression algorithms different browsers and HTTP clients support by analyzing their Accept-Encoding headers. The accept-encoding header analyzer shows browser support percentages for each encoding, helping you make informed decisions about which compression algorithms to prioritize.
Understanding Accept-Encoding Header Analysis
What is the Accept-Encoding Header?
The Accept-Encoding HTTP request header is sent by clients (browsers, curl, API clients, mobile apps) to tell the server which content compression algorithms they can decompress. The server reads this header and chooses the best Content-Encoding for the response — typically Brotli for modern browsers or GZIP as a universal fallback. Our accept-encoding header analyzer parses this header, decodes each encoding token and its q-value preference, and tells you exactly which encoding to serve for maximum compression efficiency.
How Our Accept-Encoding Header Analyzer Works
- 1Paste your Accept-Encoding header: Copy the header from browser DevTools (Network tab → request headers), from a curl
-voutput, or from your server access logs. You can paste the full header line (including the header name) or just the value. The accept-encoding header analyzer strips the header name automatically. - 2Click "Analyze Header": The accept-encoding header analyzer splits the header value on commas, parses each encoding token and its optional q-value parameter, and looks up browser compatibility and recommendations for each encoding. All processing runs in your browser — no data is sent to any server.
- 3Read the results and configure your server: The analyzer shows a support summary, the preferred encoding to serve, a detailed breakdown of each token with q-value bars, and a ready-to-use Nginx configuration snippet for the detected encoding combination.
What Gets Analyzed
- Encoding Tokens: Each comma-separated encoding in the header value is parsed individually — gzip, br, zstd, deflate, identity, and wildcard (*) are all recognized and decoded with descriptions and browser support data.
- Q-Values: The optional
q=parameter on each token indicates client preference (0.0 = refused, 1.0 = preferred). The accept-encoding header analyzer sorts tokens by q-value and visualizes preference with a bar chart. - Preferred Encoding:The analyzer determines the single best encoding to serve based on the client's supported encodings — prioritizing Brotli over Zstandard over GZIP over DEFLATE.
- Server Config Snippet: A ready-to-use Nginx configuration snippet is generated for the detected encoding combination — Brotli + GZIP fallback, Zstandard + GZIP fallback, or GZIP-only.
HTTP Content Negotiation and Accept-Encoding
HTTP content negotiation is the mechanism by which clients and servers agree on the best representation of a resource. The Accept-Encodingheader is the client's side of compression negotiation — it lists what the client can handle. The server responds with a Content-Encoding header indicating which encoding it actually used. Always include a Vary: Accept-Encoding response header when serving compressed content — this tells CDNs and caching proxies to store separate cached versions for compressed and uncompressed responses, preventing garbled output for clients that do not support compression.
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Frequently Asked Questions About Accept-Encoding Header Analyzer
An Accept-Encoding header analyzer parses the Accept-Encoding HTTP request header and decodes which compression algorithms a client supports, their preference order (q-values), and the optimal Content-Encoding to use in the response. Our free accept-encoding header analyzer runs entirely in your browser — no signup required.
The Accept-Encoding header is sent by HTTP clients (browsers, curl, API clients) to tell the server which compression algorithms they can decompress. Common values include gzip, br (Brotli), zstd (Zstandard), and deflate. The server uses this to choose the best Content-Encoding for the response.
Q-values (quality values) indicate the client's preference for each encoding, ranging from 0.0 (refused) to 1.0 (preferred). For example, "br;q=1.0, gzip;q=0.8" means the client prefers Brotli but also accepts GZIP. A q-value of 0 means the client explicitly refuses that encoding. The accept-encoding header analyzer visualizes q-values as preference bars.
Yes, completely. The accept-encoding header analyzer runs entirely in your browser using JavaScript. Your header data is never sent to any server and never leaves your device. All parsing and analysis happens locally — safe for headers from production traffic logs and internal APIs.
Yes — 100% free, forever. No signup, no account, no premium tier, and no ads. Analyze unlimited Accept-Encoding headers completely free.
Always prefer Brotli (br) when the client supports it — Brotli achieves 15–25% better compression than GZIP at equivalent quality. Use GZIP as the fallback for clients that do not support Brotli. The accept-encoding header analyzer tells you exactly which encoding to serve for each client and generates a Nginx config with both.
Chrome 123+ and Firefox 126+ added support for Zstandard (zstd) compression, which offers the fastest decompression speed of any HTTP compression algorithm. The accept-encoding header analyzer detects zstd support and recommends it for API-heavy applications where decompression speed matters more than compression ratio.
The "identity" encoding means no compression — the response is served as-is. If a client sends "identity;q=0", it explicitly refuses uncompressed responses (very rare). If no Accept-Encoding header is present at all, the server should assume the client accepts identity (uncompressed) responses.