| title | Quickstart |
|---|---|
| description | Open a diagnostic tool, run a check, and understand the result. |
Run a diagnostic from any modern browser.
Go to buffer.lol and choose a tool from the networking, IP, or developer sections. To jump directly to a tool, choose Find a tool or press Command+K on macOS or Ctrl+K on Windows and Linux.
Server-backed diagnostics ask for a target such as a domain, URL, IP address, ASN, or host:port pair. Browser-only utilities ask for the text or data you want to transform.
DNS Lookup example.com
DNS Resolver example.com + A, AAAA, CNAME, MX, NS, TXT, or CAA
Email DNS Health example.com + an optional DKIM selector
HTTP Headers https://example.com
Security Headers https://example.com
SSL Checker example.com
Port Checker example.com:443
ASN Lookup 1.1.1.1 or AS13335
Browser Latency Test and Connection Stability Test do not ask for a target. They measure repeated HTTPS requests from your browser to buffer.lol.
Choose the tool's action, such as Run check, Compare resolvers, or Inspect security headers, for server-backed diagnostics. Tools such as JSON Formatter, Base64, Hash Generator, URL Parser, JWT Decoder, and Regex Tester run directly in the browser.
Server-backed tools display structured, readable results and provide a copy action for the underlying output. The result panel also shows how long the request took. Failed requests include a requestId that can be shared when troubleshooting.
| Signal | What it tells you |
|---|---|
| DNS records | Which addresses, mail exchangers, nameservers, and text records are published |
| Resolver comparison | Whether Cloudflare, Google, Quad9, and OpenDNS return the same normalized answer set |
| Email DNS health | Whether recognizable MX, SPF, DMARC, optional DKIM, MTA-STS, and TLS reporting records are published |
| HTTP status and headers | Whether a URL responds and which caching, server, redirect, and content metadata it exposes |
| HTTP security headers | Which transport and browser security controls appear on the final response, with recommendations for missing controls |
| TLS certificate | Whether the certificate is accepted, who issued it, and when it expires |
| Port reachability | Whether a public TCP port accepts connections from the diagnostics service |
| RDAP and ASN data | Which network, registrar, country, or autonomous system is associated with a target |
| Browser latency and stability | HTTPS round-trip timing and failed requests between your browser and buffer.lol |
| Traceroute hops | The public route visible from buffer.lol's diagnostics worker |
Repeat the same check after a DNS change, deploy, certificate renewal, or firewall update. Network data can vary by resolver, route, proxy, and cache timing. Related-tool links can carry the current public target into the next check so you can continue the same investigation.
If a target works in your browser but fails in buffer.lol, check whether it blocks external probes, requires authentication, resolves to a private address, or only accepts traffic from a specific network.