Online browser check

Online browser check is a diagnostic tool for web teams to verify URL reachability and basic performance from a browser perspective. It helps QA, SEO, and operations personnel confirm that a given URL can be loaded publicly, measure response time, and spot basic issues before launch or after changes. The tool supports HTTP(S) checks, optional DNS and TLS validations, and clear output signals for quick decision making.\n\nIt operates from the tool backend, performing a DNS resolution (when enabled), issuing an HTTP GET against the target URL, and recording timings from request start to response end. Redirects are followed up to a configurable limit, and outputs include final_url, status_code, and response_time_ms. When TLS is requested, the certificate chain and expiry are evaluated to flag TLS validity.\n\nWhom it helps: product managers validating rollout readiness, SEO teams assessing site accessibility for crawlers, and uptime engineers monitoring public availability. Unique value lies in combining browser-oriented reachability with DNS and TLS insights in a single pass, enabling faster triage and more reliable publishing decisions. The tool is designed to be deterministic, lightweight, and language-agnostic.\n\nCore features and use cases include a required URL input with optional timeout, redirects cap, and TLS checks. Outputs report reachable, status_code, final_url, response_time_ms, dns_resolved, tls_valid, cert_expiry, and server_header. Use cases cover pre-launch validation, post-migration checks, and routine uptime verification. Edge cases such as DNS failures, timeouts, or invalid URLs are surfaced with explicit error codes for automation.