~ Model-estimated data·Source · Google Trends, Reddit·8h MVPRecommended

Email Deliverability Checker

Build an English-first tool site that helps newsletter creators, AI tool site operators, B2B SaaS founders

At a glance

→🟢 Recommended
→Product differentiation: this is a `domain/email deliverability audit`, not a generic AI email assistant.
→8h to an MVP · 5 competitors broken down

Market Evidence

—monthly searches~ model estimate

↗ Rising

5 direct competitors

Target users:
Newsletter creators, AI tool site operators, B2B SaaS founders, cold email teams, marketing consultants, and small-team growth marketers.
Users sending email through Google Workspace, Microsoft 365, Mailchimp, ConvertKit, Brevo, Resend, Postmark, SendGrid, or Mailgun.

Competitive Landscape

Named competitorsHello InboxMXFendEmailToolBoxMailRiskDeliverabilityChecker

Reference signals: Hello Inbox positions itself as an AI deliverability expert; GlockApps offers spam checking, inbox placement, blacklist checks, and SPF/DKIM/DMARC validation; MXFend, EmailToolBox, MailRisk, and DeliverabilityChecker cover DNS and security checks.
Competitors mainly fall into three groups:
DNS/authentication checkers: SPF, DKIM, DMARC, MX, BIMI, MTA-STS, TLS-RPT.
Inbox placement / spam tests: useful but require seed mailboxes or a receiving email system, so they are not right for the first version.
Deliverability consulting / warmup suites: service- or subscription-heavy, good for later monetization.
The gap: many tools are too technical and return raw DNS results, while others quickly push warmup or consulting. A lightweight tool for creators, indie SaaS founders, and cold email users can win by turning checks into clear next steps.

Differentiation Opportunity

- Product differentiation: this is a domain/email deliverability audit, not a generic AI email assistant.

5-Axis Scoring

Market7/10

Gap7/10

Tech7/10

SEO7/10

Revenue6/10

Why Build This

Target users:
Newsletter creators, AI tool site operators, B2B SaaS founders, cold email teams, marketing consultants, and small-team growth marketers.
Users sending email through Google Workspace, Microsoft 365, Mailchimp, ConvertKit, Brevo, Resend, Postmark, SendGrid, or Mailgun.
Real problems:
They do not know why emails land in spam.
They do not know whether SPF, DKIM, and DMARC are configured correctly.
Existing DNS tools are hard to interpret.
New sending domains feel risky.

What to Build

Target User

Newsletter creators, indie developers, AI tool site operators, B2B SaaS founders, cold email users, and marketing consultants.

Core Function

Form input:

domain

email provider

Differentiation

- Product differentiation: this is a domain/email deliverability audit, not a generic AI email assistant.

How to Monetize

Primary

Affiliate: Resend, Postmark, SendGrid, Mailgun, Brevo, ConvertKit, DMARC monitoring, email warmup, CRM.

Secondary

Paid reports: branded PDF / Markdown repair reports for clients or teams.

How to Build

Next.js

MVP Checklist

1.Build page structure and global SEO metadata.
2.Implement Checker form, validation, loading, and error states.
3.Implement DNS lookup in `app/api/check/route.ts`.
4.Implement SPF, DMARC, MX, and DKIM parsing and basic checks.
5.Implement BIMI, MTA-STS, and TLS-RPT presence checks.
6.Implement scoring and critical/warning/pass classification.
7.Implement repair recommendations and Markdown report generation.
8.Complete About, FAQ, schema, and Open Graph metadata.
9.Manually test real domains: gmail.com, github.com, and the user's own or test domain.
10.Fix mobile layout and error states.

Don't Build

✕Do not expand features without confirmation.
✕Do not add a complex backend unless core functionality requires it.
✕Do not start with login, payment, membership, or admin unless core functionality requires it.
✕Do not sacrifice launch speed for unnecessary completeness.
✕**Do not cut the core feature just to make the project lighter.**
✕Do not market DNS readiness checks as real inbox placement tests.
✕Do not send email or modify DNS automatically.

SEO Keywords

email deliverability checkeremail spam checkeremail deliverability testSPF DKIM DMARC checkerdomain email deliverability checkemail authentication checkeremail deliverability tool for startupsemail deliverability tool for newsletterswhy are my emails going to spamhow to check SPF DKIM DMARChow to find DKIM selectorDMARC none vs quarantine vs reject

Risks

△Crowded category: differentiation must come from clear explanations, fix steps, and indie SaaS/newsletter positioning.
△Accuracy risk: passing DNS authentication does not guarantee inbox placement, and the UI must state this clearly.
△DKIM risk: selectors vary by provider, so v1 needs manual selector input plus common presets.
△Maintenance risk: provider setup copy changes over time.
△SEO competition: the English homepage keyword is competitive, so long-tail pages and a strong tool experience matter.
△Monetization timing: free checks can get traffic, but paid reports and monitoring require later iteration.