Free Email Verifier & DNS Deliverability Tools
Check if an email address is valid, test MX servers, SPF lookup limits, DKIM keys, DMARC policies, and burner domains in seconds. Zero signup required.
Explore Individual Diagnostic Tools
Click any tool for dedicated tests, RFC compliance rules, and remediation guides.
MX Record Lookup
Discover active Mail Exchanger (MX) hosts, priority rankings, IPv4/IPv6 addresses, and Null MX configurations in real-time.
- Direct authoritative DNS queries via Anycast resolvers
- Null MX detection (RFC 7505) for domains that never accept email
SPF Record Validator
Validate Sender Policy Framework syntax, recursively trace include trees, and safeguard against the strict 10-lookup DNS limit.
- Recursive expansion of all `include:` and `redirect=` chains
- Exact RFC 7208 DNS lookup count counter (hard ceiling: 10)
DKIM Key Checker
Probe over 45 industry-standard DKIM selectors, inspect public RSA/Ed25519 cryptographic keys, and confirm cryptographic strength.
- Simultaneous probe across 45+ top ESP selectors (Google, AWS, SendGrid, Postmark)
- Cryptographic key length analysis (1024-bit vs modern 2048-bit standard)
DMARC Policy Analyzer
Audit DMARC records at _dmarc.<domain>, verify p=reject enforcement, check organizational inheritance, and inspect aggregate reporting.
- Exact tag parsing (`v`, `p`, `sp`, `pct`, `rua`, `ruf`, `adkim`, `aspf`)
- Organizational domain fallback resolution (subdomain to root)
Disposable Domain Checker
Check any domain against BounceLayer's in-memory list of over 100,000 throwaway, temporary, and 10-minute inbox services.
- Sub-millisecond in-memory Trie scanning across 100,000+ domains
- Dynamic catch-all pattern matching for wildcard burner providers
Email Checker
Instant keyless diagnostic inspecting RFC 5322 syntax grammar, authoritative MX records, role accounts, and free email providers.
- Strict RFC 5322 grammar and character set evaluation
- Immediate MX availability and Null MX verification
Blacklist Checker
Scan IPv4 addresses and domains against authoritative DNS blocklists (Spamhaus, Barracuda, SORBS, SURBL, SpamCop) in parallel.
- Parallel queries across 11+ industry DNSBL/RBL zones
- Spamhaus ZEN, Barracuda BRBL, SpamCop, and SORBS support
Why Email Authentication Matters in 2026
Google Workspace, Yahoo Mail, Microsoft 365, and Apple Mail require strict compliance with foundational RFC standards. Failure to configure these records results in immediate junk folder placement or outright bounce codes (550).
SPF 10-Lookup Ceiling
RFC 7208 limits SPF lookups to 10 DNS queries. Merging multiple SaaS tools easily exceeds this threshold, throwing silent PermError codes.
DMARC Alignment & Enforcement
A policy of p=none only reports. Migrating to p=reject actively stops cybercriminals from spoofing your domain.
Disposable Email Protection
Temporary disposable inboxes degrade deliverability and inflate fake user counts. Gating signups protects sender reputation.
Frequently Asked Questions
Why are these tools free?
BounceLayer provides keyless public diagnostic utilities to help senders debug email authentication standards without barriers. For mailbox-level verification, our API offers 100 free credits.
How does DNS querying work?
Our diagnostic engine queries authoritative nameservers directly via high-speed asynchronous DNS resolvers, bypassing stale intermediate caches.
2026 Sender Requirements?
Senders must have valid SPF and DKIM authentication, an active DMARC policy, spam complaint rates below 0.3%, and functional reverse DNS (PTR).
Ready for Full Real-Time Mailbox Verification?
Authenticate recipient inboxes in real-time with sub-140ms direct SMTP handshakes, catch-all intelligence, and bulk list verification.