Email evidence,
made actionable.
Mailybox turns DNS, headers, SMTP failures and production email code into an understandable evidence model — so you can diagnose the cause, test the change and verify the result.
Four evidence layers are evaluated together, not as isolated pass/fail checks.
Start with the problem, not the protocol.
Each tool begins with a real question: why did delivery fail, what does this domain depend on, where did a conversation change identity, or what will break if a record changes.
Mail Failure Doctor
Turn a bounce, NDR or SMTP rejection into a precise diagnosis and a prioritized fix plan.
Open analysis →Email Infrastructure Digital Twin
Map the public email control plane of a domain and expose dependencies, weak points and provider fingerprints.
Open analysis →BEC Conversation Hijack Analyzer
Compare two messages in the same business conversation and expose sender, reply-path, signing and domain changes that deserve independent verification.
Open analysis →AI Agent Email Permission Graph
Model the blast radius created by an email agent’s read, send, attachment, contact and delegated-tool permissions before granting mailbox access.
Open analysis →Email Deliverability Forensics Lab
Inspect a complete .eml message for identity, authentication, delivery route, MIME structure, attachment metadata and visible tracking surfaces.
Open analysis →Email Compliance Compiler
Compile a sending domain and campaign HTML into one evidence-bounded provider-readiness report.
Open analysis →SPF Dependency Graph
Resolve SPF recursively, count DNS-triggering mechanisms and reveal the exact path to PermError risk.
Open analysis →DMARC Aggregate Report Analyzer
Turn DMARC aggregate XML into source-level pass rates, dispositions, policy evidence and prioritized failing senders, including RFC 9990 DMARC 2.0 reports.
Open analysis →Email Chaos Lab
Generate realistic SMTP and webhook failure scenarios for transactional-email resilience testing.
Open analysis →HTML Email Preflight
Inspect HTML size, clipping risk, accessibility, tracking, links and email-client compatibility hazards.
Open analysis →Start from the bounce, NDR or SMTP response and work backward to the likely cause.
Resolve dependency chains instead of treating DNS records as isolated strings.
Turn headers into identities, hops, delays and authentication evidence.
Model authentication and policy effects before publishing a risky change.
Email rules are moving. Your diagnostics should move with them.
Current standards and provider changes are built into task-specific analysis rather than left as static reference text.
Browse current field guidesInventory web Send as, Gmailify and POP dependencies against Google’s published transition.
Trace current Organizational Domain discovery instead of substituting a static suffix guess.
Read current reporting metadata, sender volume and authentication outcomes in one evidence view.
Compare the earlier and later message when a payment or supplier thread no longer feels consistent.
Map the abuse paths created when an agent can read, send, forward attachments or delegate mailbox-derived actions.
Technical depth without the maze.
Guides explain the failure modes behind the tools and link every concept back to something you can verify.
Gmail 2027 Third-Party Account Changes: Audit Send As, POP and Gmailify Dependencies
Identify Gmail web workflows affected by the January 2027 third-party account changes and plan replacements early.
Read guide →DMARC RFC 9989 DNS Tree Walk: How Organizational Domain Discovery Changed
Understand the current DMARC policy-discovery and alignment algorithm, including the eight-query bound and psd boundaries.
Read guide →Business Email Compromise Thread Forensics: Find the Identity Break
A disciplined way to compare messages inside a business conversation without treating one suspicious field as proof of fraud.
Read guide →Email Agent Permission Modeling: Map Blast Radius Before Mailbox Access
A practical method for scoping AI email-agent capabilities, approval boundaries and external-send risk before production authorization.
Read guide →Have an error message right now?
Paste it into Mail Failure Doctor. Mailybox will classify the provider, failure family and next verification steps.