Common workflows: From first upload to outbound dispatch
A reliable email hygiene workflow prevents bad data from ever reaching your sending infrastructure. High-volume senders maintain five disciplined lifecycle steps:
| Lifecycle Stage | Recommended User Action | Tooling & Interface | Deliverability Protection |
|---|
| 1. Ingestion | Export clean CSV with UTF-8 encoding; keep CRM IDs intact. | Portal File Uploader / REST Bulk API | Prevents corrupted character encodings & attribute loss. |
| 2. Verification | Run automated 4-stage checks (Syntax, DNS MX, SMTP, 6-hr Disposables). | MailCheckup Verification Engine | Quarantines dead mailboxes & temporary burner addresses. |
| 3. Audit & Review | Review summary counts; verify Deliverable, Catch-All, and Free Unknowns. | Portal Dashboard / Webhooks | Isolates high-risk segments before touching outbound domains. |
| 4. Segmentation | Filter into Deliverable (primary outreach) and Catch-All (secondary). | Segmented CSV Export / MCP Prompt | Ensures secondary domains protect primary company.com. |
| 5. Outbound Dispatch | Enroll valid leads into sequencers (Instantly, Smartlead, HubSpot). | Cold Email Sequencer / ESP | Guarantees hard bounce rate stays safely below 1.0%. |
Credit accounting & billing rules at a glance
MailCheckup operates on a transparent, mathematical billing model: you pay only for finished, definitive answers. Inconclusive outcomes cost nothing:
| Result / Outcome | Charge Status | Credit Deducted | Explanation & Operational Rule |
|---|
| Deliverable (Valid) | Chargeable | 1 Credit | Mailbox verified via SMTP 250 OK handshake. |
| Undeliverable (Dead) | Chargeable | 1 Credit | Mailbox rejected via SMTP 550 User Unknown or missing MX. |
| Catch-All (Accept-All) | Chargeable | 1 Credit | Server accepts all recipients unconditionally. |
| Disposable (Burner) | Chargeable | 1 Credit | Domain matched against 97k+ 6-hour updated blocklist. |
| Role-Based (Functional) | Chargeable | 1 Credit | Function mailbox (sales@, info@, billing@). |
| Mailbox Full (Storage) | Chargeable | 1 Credit | Storage quota exceeded (552/452 limit). |
| Unknown (Greylisted) | 100% Free ($0) | 0 Credits (Released) | Remote timeout, temporary 451 greylisting, or firewall deferral. |
| Duplicate in List | 100% Free ($0) | 0 Credits | Repeated addresses inside a single list are checked once. |
Troubleshooting verification results & deliverability issues
Diagnose and resolve common deliverability symptoms before domain sender reputation is compromised:
| Observed Deliverability Issue | Root Cause Diagnosis | Immediate Corrective Action |
|---|
| Bounce rate spiking above 2% on outreach | Sending to unverified lists or dormant scraped contacts. | Scrub list with MailCheckup; purge all 550 dead & burner rows. |
| High proportion of B2B contacts marked Catch-All | Target company uses Exchange/Google catch-all security. | Do not blast from primary domain; test via secondary warmed inboxes. |
| Registration form timeouts during signup | Verification API taking >300ms on upstream greylisted MTAs. | Implement fail-open pattern with 250ms AbortSignal budget. |
| Custom lead columns missing after verification | Third-party tool stripped CSV metadata during processing. | Use MailCheckup CSV export; schema & custom columns remain 100% intact. |
| Google Workspace / Yahoo domain throttling (421) | Volume spike combined with spam complaints >0.3%. | Align SPF/DKIM/DMARC; enforce pre-send list hygiene on all cadences. |
Official support channels & business facts
Our support and engineering teams are directly accessible without automated runarounds:
Technical & Deliverability Support: Contact support@mailcheckup.net for questions regarding SMTP result codes, DNS MX routing, API rate limits, or MCP tool configurations.
Billing & Invoices: Contact billing@mailcheckup.net for Stripe Checkout inquiries, receipt requests, or voluntary 7-day refund evaluations. Invoices are issued by Secuno LLC, number format MCU-YYYYMMDD-####.
Corporate Headquarters: Secuno LLC, 30 N Gould St, Sheridan, Wyoming, USA 82801. Telephone: +1 (315) 961-7074.
Frequently asked questions (Help Center)
How do credit holds work during list verification?
When you start a verification run, MailCheckup calculates the maximum potential credits required and places a temporary hold on your account balance in chunks. As addresses are processed, chargeable results consume one credit each. If an address returns an unknown, greylisted, or timed-out outcome, no credit is consumed and that portion of the hold is immediately released back to your available balance.
Do purchased credit packs ever expire?
Credit packs do not expire. Any credits purchased through on-demand packs (such as 5,000 credits for $15 or wholesale packs up to 1,000,000 credits) remain in your workspace permanently until consumed. Only credits included with monthly recurring plans expire at the end of the paid billing cycle.
What is MailCheckup's voluntary 7-day refund policy?
Our voluntary refund request window is seven days after payment. If you experience technical issues or are dissatisfied with a purchase, submit a request to billing@mailcheckup.net within seven days. Unused credits from the eligible transaction will be refunded via Stripe Checkout.
How does stopping a subscription affect remaining credits?
Cancelling a monthly subscription stops future renewal charges. Your existing account remains active, and any purchased on-demand credit packs remain untouched in your balance. Monthly plan credits remain usable until the end of your current paid billing period.
Can I re-verify unknown contacts later without paying twice?
Yes. Because unknown outcomes are 100% free ($0), running them initially consumed zero credits. You can export the unknown segment and re-verify it hours or days later (after remote mail server greylisting deferrals expire). If the subsequent check returns a definitive deliverable or undeliverable outcome, it will use standard credits for the finished answer.
How does MailCheckup handle data security and GDPR Article 28 compliance?
MailCheckup acts strictly as a Data Processor under GDPR Article 28. Contact lists uploaded for verification are processed in volatile memory and are never sold, rented, monetized, or shared with third parties. Workspace API keys are encrypted at rest, and webhook payloads are cryptographically signed with HMAC-SHA256.
What happens if my CSV has duplicate email addresses?
MailCheckup automatically deduplicates identical email addresses within a single list upload. The unique address is verified once, and only a single credit is charged. All instances in your original spreadsheet receive the verified result upon export.
How do I reach human support if I have a question about my account?
Technical and product support is available at support@mailcheckup.net. Billing questions and invoice inquiries are handled at billing@mailcheckup.net. Official invoices are issued by Secuno LLC (30 N Gould St, Sheridan, WY 82801, USA).
