How I built errno.help - and what broke along the way

Описание и применение

errno.help объединяет часто используемые инструменты для разработчиков в одном веб‑приложении, обеспечивая клиент‑сайд обработку и безопасные серверные запросы, улучшая эффективность работы и доверие.

Задача

Developers repeatedly use multiple online tools for CIDR math, JWT decoding, hashing, etc., leading to fragmented workflows and trust concerns.

Результат

errno.help consolidates common IT/dev utilities into a single, client‑side first web app with secure server‑side services, robust rate limiting, and a clean design, improving workflow efficiency and trust.

Рабочий процесс

• 1. Identify core utilities (CIDR, JWT, hash, UUID, YAML⇄JSON, cron, DNS/WHOIS/ASN/GeoIP, Windows error reference, command builders).
• 2. Implement client‑side logic using native Web APIs (crypto, randomUUID).
• 3. Add server‑side Next.js API routes for DNS, WHOIS, ASN, GeoIP, port checker, ensuring no client‑side API keys.
• 4. Configure GeoIP provider: switch from MaxMind to ipinfo.io for easier auth and commercial‑friendly free tier.
• 5. Implement rate limiting keyed on X‑Forwarded‑For, then adjust to use x‑real‑ip on Vercel and httpOnly cookie IDs elsewhere.
• 6. Resolve layout issue by moving viewport lock to landing page root instead of global body.
• 7. Deploy to Vercel, test, iterate.
• 8. Open‑source under MIT on GitHub.
• 9. Plan future feature additions (Base64, regex, more command builders).

Доказательства

Nothing you paste into the JWT decoder ever leaves your machine

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The GeoIP service rejected our credentials.

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rate limiting keyed on X-Forwarded-For can be trivially bypassed

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