--- title: "Email Verification Methodology | How Refresh List Checks Lists" description: "Read how Refresh List separates local preflight from provider-backed mailbox verification, accounts for credits, preserves uncertainty, and documents limitations." url: https://refreshlist.net/verification-methodology last_updated: 2026-09-25 --- [Refresh List](/) › Verification methodology EVIDENCE REGISTER / VERIFICATION METHODOLOGY # Know what was checked. Know what was not. Refresh List separates file assessment from provider-backed mailbox verification. The result is a traceable workflow that keeps valid, invalid, and unknown outcomes distinct, preserves source-row context, and states the limits beside the result. Last reviewed 18 September 2026 · No independent accuracy guarantee claimed THE SHORT ANSWER ## How does Refresh List verify an email list? First, RefreshScan inspects the file locally. After you review the eligible unique count, the authenticated workspace sends only those addresses to the configured verification provider. Refresh List records the provider outcome and reason, reconciles credits, and returns categorized exports with the original row context. LOCAL PREFLIGHT STRUCTURE, NOT MAILBOX Duplicates and skipped rows are identified before any paid check. PROVIDER CHECK OUTCOME, NOT PROMISE Provider evidence is reported with its uncertainty and checking context. 01 / THE PIPELINE ## Four stages. One auditable handoff. 01 ### Inspect Parse the selected email column, count rows, detect malformed values, and map repeated addresses. 02 ### Approve Review the maximum unique requirement and reserve credits only after the input is understood. 03 ### Verify Send eligible unique addresses to the configured provider. Surrounding columns stay in Refresh List. 04 ### Reconcile Match returned rows to the source, keep reasons visible, settle credits, and export result groups. 02 / RESULT MODEL ## Outcome, signal, limitation. A provider response can answer one question without answering every question about an address. Refresh List keeps the core outcome separate from additional signals such as role, catch-all, or disposable classifications when supported. VALID Available evidence supports a positive mailbox result at the time of checking. INVALID Available evidence supports a conclusive failure for the checked address. UNKNOWN The evidence is inconclusive. Unknown is not silently changed to valid or invalid. IMPORTANT DISTINCTION Valid is not delivery. Verification cannot account for sender reputation, message content, consent, receiving policy, timing, or later mailbox changes. [Read the result status guide](/result-status-guide) 03 / CREDIT ACCOUNTING ## Every completed check has a visible cost. Refresh List uses a simple rule: one completed unique check uses one credit, regardless of whether the outcome is valid, invalid, or unknown. Duplicate and skipped rows are removed from the eligible set before verification. 100 source rows 12 duplicates and skipped 88 maximum unique checks 88 credits if all complete A reservation is not the final bill. Unprocessed work can be returned at settlement; completed unknown checks remain chargeable because verification work was performed. 04 / WHAT THE METHOD DOES NOT CLAIM ## Boundaries are part of the method. No universal accuracy percentage Provider performance varies by address, domain, time, and receiving behavior. Refresh List does not publish an unsupported benchmark. No comprehensive signal dataset Role, catch-all, and disposable signals depend on supported provider evidence or documented coverage. No delivery guarantee A mailbox outcome cannot guarantee that a later message will be accepted or read. COMMON QUESTIONS ## Methodology questions, answered. Does Refresh List verify every email address the same way?+ Refresh List sends eligible unique addresses to the configured verification provider. Provider evidence and reasons determine the recorded outcome; Refresh List does not invent a confidence score or claim a universal accuracy rate. Is local preflight an SMTP or mailbox test?+ No. Local preflight checks file structure, duplicates, and eligibility in the browser. It does not contact a mailbox or establish whether an inbox exists. What do valid, invalid, and unknown mean?+ They are distinct provider-backed outcomes. Valid means the available evidence supports a positive result at that time; invalid means a conclusive failure; unknown means the available evidence was not conclusive. How are credits counted?+ Each completed unique check uses one credit, including valid, invalid, and unknown outcomes. Duplicate and skipped rows are excluded before verification. Unprocessed reservations can be returned at settlement. Can verification guarantee delivery?+ No. Receiving systems, sender reputation, consent, message content, timing, and policy can affect delivery. Verification is evidence about a checking moment, not a delivery promise. THE METHOD ## EVIDENCE FIRST. UNCERTAINTY VISIBLE. Read the result, the reason, the accounting, and the limitation together. [OPEN RESULT GUIDE](/result-status-guide) [Review the trust center](/trust) ## Sitemap - [All Public Pages](https://refreshlist.net/sitemap.md) - [Email Glossary](https://refreshlist.net/glossary) - [Read This Page And Use Interactive Features](https://refreshlist.net/verification-methodology)