Docs

Inbox placement testing for diagnostic seed evidence.

Use diagnostic seed inbox tests, provider evidence, repeat runs, and real-message reports to investigate inbox, spam, promotions, delayed, and missing outcomes.

What placement tests can prove

A seed test gives controlled evidence about how a campaign appears in configured inboxes. It is useful for diagnosis, but it is not a substitute for real engagement and reputation data.

  • Classify inbox, spam, promotions, updates, delayed, and missing outcomes.
  • Use a subject marker to match campaign messages.
  • Poll seed inboxes over IMAP for diagnostic evidence.
  • Schedule diagnostic tests or send one user-authorized SMTP message to configured seeds.

Seed inboxes and authorized diagnostic send

Placement diagnostics need at least one seed inbox with IMAP access. Authorized diagnostic send is optional: it stores encrypted SMTP credentials from a sender you own, then sends one diagnostic message only to your configured seeds.

  • Seed inboxes are read over IMAP to classify inbox, spam, promotions, updates, delayed, or missing results.
  • Subject markers connect the message you send to the placement test that should poll it.
  • Use your ESP or SMTP provider credentials only when you want WillItInbox to send the seed message for you.
  • You can skip SMTP credentials and send the marked message manually from Gmail, SMTP2GO, your app, or your ESP.

Dashboards and schedules

After polling, placement results roll into provider coverage, heatmaps, trends, test detail, and optional recurring schedules.

  • Provider coverage shows which seed providers are configured and healthy.
  • Heatmaps summarize recent inbox, spam, promotions, missing, and total results by provider.
  • Schedules reuse active seed inboxes so teams can run recurring diagnostics without rebuilding the setup.

What placement tests cannot prove

A small seed list cannot guarantee every recipient will see the same folder. Recipient history, engagement, provider reputation, and personal filters still matter.

Good for QA

Use before major sends to catch obvious spam-folder or missing-message issues.

Good for comparison

Run before and after DNS, template, or ESP changes.

Not a warmup tool

Diagnostic seed tests do not create engagement or repair sender reputation.

Placement diagnostics

Use seed tests as controlled evidence, not a universal prediction

Inbox placement diagnostics answer a narrow but valuable question: where did this marked message land in the configured seed inboxes at this point in time? That sample is useful for QA and comparison, but it does not guarantee every real recipient will see the same folder.

Seed-test workflow

Create the test, send a marked production-like message, poll seed inboxes, classify folders, then retest after meaningful fixes.

Real-message evidence

Pair placement results with a deliverability report so authentication, DNS, headers, content, and links are not guessed.

Provider reputation

Use Google Postmaster and Microsoft SNDS as provider-specific context when enough traffic exists.

Provider evidence matrix

Combine placement samples with provider and sender evidence

A placement result is strongest when it is interpreted alongside independent signals. When several surfaces point to the same issue, the fix order becomes clearer.

SurfaceWhat it helps explainWhere to use it
Seed inbox resultInbox, spam, promotions, delayed, missing, or provider-specific folder outcome./docs/inbox-placement
Google PostmasterGmail-side reputation, spam rate, authentication, and compliance trends./blog/google-postmaster-tools-walkthrough
Microsoft SNDSOutlook IP traffic, complaint, trap-hit, filter-result, and HELO evidence./blog/snds-microsoft-guide
DNSBL/domain monitoringBlocklist, DNS, authentication, PTR, TLS, and provider-evidence drift./docs/domain-monitoring
Real-message reportAuthentication, infrastructure, headers, content, links, and prioritized fixes./tools/email-deliverability-tester

Placement vs deliverability

Run both tests when the launch matters

A deliverability test explains the message and sender path. A placement diagnostic samples folders. They answer different questions and become more useful together.

QuestionDeliverability testPlacement diagnostic
Is the message technically ready?Best first step for SPF, DKIM, DMARC, DNS, headers, content, and links.Useful after technical blockers are understood.
Where did the seed message land?Does not classify seed folders.Classifies inbox, spam, promotions, delayed, missing, and provider outcomes.
Can this guarantee recipient inboxing?No. It produces technical evidence.No. It produces a controlled sample.

Repeat-test interpretation

Compare like with like or the result becomes noise

Repeat placement tests only mean something when the sender path, template, seed set, subject marker, timing, and provider mix are recorded. Treat every run as an experiment with a clear change log.

  • Retest after ESP, DNS, template, link, audience, or authentication changes.
  • Avoid comparing a staging sender against a production sender.
  • Investigate missing results separately from spam-folder results.
  • Use provider evidence before assuming a content edit caused a placement change.

Evidence quality

A deliverability test is only useful when it uses the real send path

A forwarded proof, pasted HTML body, or staging message through a different sender can hide the exact problems that mailbox providers will see. The strongest test uses the production-like application, ESP, sender domain, DKIM selector, Return-Path, tracking links, and final template.

  • Generate a fresh test address in /test.
  • Send the message from the same system that will send to users or subscribers.
  • Review the sample report to understand how category scores become prioritized fixes.

Fix order

Prioritize receiver gates before polish

Authentication and infrastructure failures usually deserve attention before content refinements because receivers evaluate sender identity and connection quality before trusting the body. After that, required headers, unsubscribe handling, MIME quality, and links shape the final risk profile.

LayerCommon issueFirst action
AuthenticationSPF/DKIM/DMARC missing or unalignedFix DNS/provider configuration, then retest.
InfrastructurePTR, HELO, TLS, or blocklist issueCorrect the sender host or investigate the listing cause.
HeadersMissing List-Unsubscribe or Message-IDFix the mailer or ESP template settings.
ContentHTML-only, image-heavy, or suspicious linksImprove MIME structure and link hygiene.

Plan model

Pricing uses clear usage quotas plus feature access

WillItInbox plans are easiest to understand when the metered usage stays simple: deliverability tests, email validations, API calls, and bulk CSV rows. Monitoring, webhooks, workspaces, branded reports, placement diagnostics, and trust-layer APIs are shown as feature access until those surfaces need explicit capacity counters.

  • Tests measure generated deliverability reports and placement diagnostics.
  • Validations measure single, batch, API, and bulk recipient checks.
  • API calls cover authenticated automation, including trust-layer ingestion endpoints.
  • Bulk rows cap CSV validation job size and recurring list-hygiene volume.

Newer surfaces

Feature pages carry the detail pricing should not

The pricing page should stay scannable. The docs and feature pages should explain what the newer surfaces do, what evidence they produce, and where they fit in a sender's workflow.

DMARC intelligence

The DMARC docs explain DMARC aggregate/RUF/TLS-RPT separation, mailbox ingestion, source labels, forensic-report handling, and alerts.

Provider reputation

Connect Google Postmaster for read-only domain evidence, compliance status, and latest Gmail-side reputation snapshots.

Inbox placement diagnostics

Diagnostic seed tests, schedules, user-authorized SMTP sends, and provider heatmaps are documented as evidence, not a placement guarantee.

Trust-layer APIs

DSN bounce ingestion, ARF complaint ingestion, and suppression-aware validation are API-backed workflows for operational hygiene.

FAQ

Does an inbox placement test guarantee inbox delivery?

No. It shows where a controlled seed sample landed. Real recipients can differ because of reputation, engagement, recipient history, content, timing, and provider behavior.

When should I run placement diagnostics?

Run them before important campaigns, after sender-path changes, during reputation incidents, and when provider-specific behavior needs evidence beyond a technical message report.

When should I rerun a deliverability test?

Retest after DNS changes, ESP migrations, template edits, tracking-domain changes, new sending subdomains, and before important campaigns or product-email releases.

Should transactional and marketing email be tested separately?

Yes. They often use different templates, headers, links, sender domains, and risk profiles.

Does every newer feature have its own public rate limit?

No. WillItInbox exposes four clear usage quotas today: tests, validations, API calls, and bulk rows. Other workflows are handled as feature access or beta access unless a concrete capacity limit is added later.

Why keep placement and trust-layer language careful?

Placement tests provide diagnostic seed evidence, and trust-layer APIs provide operational ingestion and suppression evidence. Neither should be described as a guarantee of inbox placement or compliance certification.