Technical SEO tools for crawling, indexing and website engineering
Free individual checks and generators · without registration
Examine HTTP responses, redirects, language versions, and technical data formats. Select the check to match the observed error and check for changes to specific URLs.
HTTP Responses and Accessibility
- HTTP status code checkerChecks HTTP status codes for URL, URL list or sitemap and shows 200 OK, 301/302, 404/410, 5xx and final destination URL.
- Bulk Status Code CheckerChecks up to 50 entered URLs via HEAD: final status, destination URL and number of redirects for a fixed checklist.
- HTTP Header CheckerRead the final server response with fixed retrieval options and explain important HTTP headers right next to the values. With copying and CSV export.
- Get headersCompare HTTP responses with GET and HEAD.
- User Agent Response Diff CheckerCompares HTTP responses for two user agents and header profiles: status, destination URL, SEO specifications, selected headers, and static content.
- Soft 404 CheckerCheck error pages with HTTP 200 against Title, H1, content, and an optional comparison error page. Shows concrete evidence of the suspicion.
- Website Down CheckerCheck website accessibility for free: HTTP status, forwardings, destination address and response time from the Seitenreport server. Without registration.
Planning and testing of forwardings
- Redirect CheckerChecks redirect chains (301/302/307/308), final destination URL, www/non-www & HTTP→HTTPS, detects loops and (optional) canonical conflicts.
- Redirect Map GeneratorCreates a clean redirect map for relaunches and migrations – as CSV and for Apache or Nginx redirects.
- Redirect Regex TesterSimulates Apache and Nginx forwards with sample URLs. Shows rule overlaps, query parameters, chains and loops.
- .htaccess generatorCreate HTTPS, host variant, GZIP, caching, and error page as Apache rules.
- HTTPS CheckerChecks HTTPS forwarding, certificate, and HSTS – to detect incorrect destination URLs or certificate issues after an HTTPS changeover.
- WWW / non-WWW CheckerCheck whether www and non-www forward to a preferred target version – without double accessibility and without unnecessary redirect detours.
Language versions, domains and accesses
- Hreflang CheckerChecks language codes, references and canonical conflicts – to find errors in the hreflang linking of international sites.
- hreflang generatorCreates clean hreflang tags for international setups with language/country codes, x-default and copy-and-paste-ready markup.
- CMS CheckerWhich CMS uses a website? Recognize WordPress, TYPO3, Shopify and other systems based on public HTML signals. Free of charge with specific references.
- WHOIS & Domain Age CheckerCheck domain age and WHOIS data for free: age from the registration date, registrar, status and nameserver. With source and clear boundaries in the case of missing data.
- Reverse DNS / PTR CheckerCheck Reverse DNS for free: Resolve IPv4 or IPv6 in PTR hostnames and compare them to the forward resolution. With clear error assignment.
- CORS CheckerCheck CORS for free: Compare Origin, Credentials, desired method and header with GET and OPTIONS responses. Without transmitting access data.
- Punycode/IDN converterConvert IDN domains into Punycode for free and decode them readably. Up to 100 domains, Unicode and ASCII output, completely local in the browser.
Preparing data and code
- JSON Validator and FormatterValidate JSON for free, format readable or minimize it. With syntax errors, warning on duplicate keys and receiving large numbers. Locally in the browser.
- XML Validator and FormatterCheck XML for well-formedness free of charge and format readably. With namespace support, mixed content protection, and local file upload.
- YAML Validator and FormatterValidate and format YAML for free. Check syntax errors, duplicate keys, multiple documents and anchors. File import locally in the browser.
- JSON ↔ CSV converterConvert JSON to CSV and CSV to JSON for free. With separator selection, column selection, exact large numbers and local file import.
- XML ↔ JSON converterConvert XML and JSON for free. With attributes, namespaces, repeated elements, and an ordered model for mixed content. Locally in the browser.
- Base64 Encoder/DecoderCode or decode text and files for free as Base64. UTF-8, Base64URL and Data URIs, with binary download and no upload.
- RegEx testersTest RegEx for free: Hits, positions, groups and replacements with JavaScript RegExp. With flags, time limit and local export.
- URL Encoder/DecoderLocally encode or decode URLs and individual parameters; check duplicate encoding and plus signs.
- HTML Entities Encoder/DecoderLocally encode HTML special characters or decode them once; copy the result and save it as text.
Then they join the exams.
Limit the error reproducibly
Write down the affected URL and the observed status. First check individual addresses directly; a checklist can then be evaluated collected.
HTTP status code checkerSimulate forwarding before installation
Assign old URLs to matching goals and test rules with successful and unwanted sample hits. The simulation does not replace the test of your server configuration.
Redirect Regex TesterCheck the delivered response
After installation, the answers of the server count. Check status, destination address and header again; for bot differences, specifically compare the user agents.
HTTP Header Checker
Frequent questions
Which header check should I choose?
The HTTP header checker explains the final response with fixed retrieval options. Get Header is suitable for targeted comparisons with GET and HEAD. The User-Agent-Diff compares different request variants.
Are server rules automatically installed by a generator?
No. The tools create or simulate templates. You check and incorporate these yourself into your server configuration and then control the actual answers.
Checking the website in connection
The free SEO check examines up to 20 URLs and bundles findings and prioritized measures.