Developer Tools vs Highlight.io

devtools.tr is a free toolbox of 173 web and developer tools for webmasters, developers and system administrators. Every check runs live against real servers: DNS lookup, SSL/TLS and security headers, website analyzer with PDF reports, SEO and Core Web Vitals, TTFB, CDN and compression tests, IP geolocation, WHOIS, ASN and blacklist checks. Developer utilities include a JSON formatter and validator, regex tester, Base64, UUID, SQL/HTML/CSS/JS formatters and minifiers. Results come as clear reports with scores and ready-to-paste fixes for Apache, nginx and Cloudflare. No sign-up, no limits, fully in English and Turkish, and works on mobile.

Highlight.io is an open-source monitoring platform that combines session replay, frontend and backend error monitoring, logging and distributed tracing in one product. It was acquired in 2025 by feature flag vendor LaunchDarkly, which built its own observability product on Highlight's technology. The hosted Highlight.io service was retired at the end of February 2026 and customers were moved to LaunchDarkly Observability; the open-source code remains available for self-hosting.

The core workflow ties a user-facing problem to its root cause: a session replay shows what the user did, and the error that occurred is linked to the backend trace and to the logs emitted during that request. SDKs cover popular frontend frameworks and backend languages, and OpenTelemetry is supported for traces and logs. The code is open source and can still be self-hosted; while it ran, the hosted version offered a free tier with a monthly allowance of sessions, errors and logs and pay-as-you-go pricing above that.

Today Highlight mainly suits teams that want to self-host replay and errors in one tool and can maintain the code themselves, since the project no longer has an official hosted service or vendor roadmap. Teams that want the same approach as a managed product should evaluate LaunchDarkly Observability, especially if they already use LaunchDarkly. Sentry offers deeper error monitoring and its own session replay with a much larger community, LogRocket and PostHog are strong on product-side replay and analytics, and OpenReplay is another self-hostable open-source replay option.