Quickstart

Run a diagnostic from any modern browser.

1. Open the toolbox

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.

2. Enter a target

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.

3. Run the check

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.

4. Interpret the output

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

5. Compare when needed

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.

Getting Started

IP Lens

Concepts

API Reference

Quickstart

Quickstart

1. Open the toolbox

2. Enter a target

3. Run the check

4. Interpret the output

5. Compare when needed

​Quickstart

​1. Open the toolbox

​2. Enter a target

​3. Run the check

​4. Interpret the output

​5. Compare when needed

Quickstart

1. Open the toolbox

2. Enter a target

3. Run the check

4. Interpret the output

5. Compare when needed