6 Free Developer Tools You Can Use Right Now (No Signup Required)

Sometimes you just need a quick tool to check something. Is my SSL certificate expiring? What DNS records does this domain have? Is that port open?

I built these tools for Boop because I kept needing them myself. They are completely free, no signup required, and work right in your browser.

1. SSL Certificate Checker

URL: boop.one/tools/ssl-checker

Check any domain's SSL certificate instantly:

• Certificate expiration date
• Certificate chain validation
• Issuer information
• Days until expiry

Use case: Quick check before your cert expires and Chrome starts showing scary warnings to your users.

2. DNS Lookup

URL: boop.one/tools/dns-lookup

Query DNS records for any domain:

• A, AAAA, CNAME, MX, TXT, NS records
• Multiple record type support
• Raw DNS response data

Use case: Debugging DNS propagation, checking MX records before setting up email, verifying TXT records for domain verification.

3. HTTP Headers Checker

URL: boop.one/tools/http-headers

See exactly what headers a URL returns:

• Response status code
• All response headers
• Security headers check
• Cache control settings

Use case: Debugging CORS issues, checking security headers, verifying cache settings.

4. WHOIS Lookup

URL: boop.one/tools/whois-lookup

Get domain registration information:

• Registrar details
• Registration and expiry dates
• Nameserver information
• Domain status

Use case: Checking when a domain expires, finding out who owns a domain, verifying domain transfers.

5. Ping Tool

URL: boop.one/tools/ping

Test if a host is reachable:

• Response time measurement
• Packet loss detection
• Multiple ping support

Use case: Quick connectivity check, latency testing, verifying a server is up.

6. Port Checker

URL: boop.one/tools/port-checker

Check if specific ports are open:

• TCP port scanning
• Common port presets
• Custom port input

Use case: Verifying firewall rules, checking if services are exposed, debugging connection issues.

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Why Free?

Honestly? These tools bring people to Boop. Some of them end up signing up for monitoring (which is what we actually sell). But even if you never sign up, these tools are genuinely useful and I wanted them to exist.

Need Ongoing Monitoring?

If you find yourself checking these things repeatedly, you might want automated monitoring instead. Boop monitors your sites every 30 seconds from 4 global regions and alerts you when something goes wrong.

Free tier includes 10 monitors. No credit card required.

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What other tools would be useful? Drop a comment - I might build it.