B2B signup quality, email intelligence, and Google Workspace / Microsoft 365 detection.https://isbusinessemail.comenhttps://isbusinessemail.com/blog/check-emails-from-ai-assistants-mcphttps://isbusinessemail.com/blog/check-emails-from-ai-assistants-mcpConnect isBusinessEmail's MCP server to Claude, ChatGPT, Cursor or VS Code, then ask which emails are work emails and which companies use Microsoft 365.Mon, 05 Oct 2026 00:00:00 GMTmcpapisaleslead-scoringhttps://isbusinessemail.com/blog/domain-age-fraud-signalhttps://isbusinessemail.com/blog/domain-age-fraud-signalA domain registered days ago is a real risk signal at sign-up, not proof of fraud. How to check domain age with RDAP and when to review instead of block.Mon, 05 Oct 2026 00:00:00 GMTfraudsignupapipolicyhttps://isbusinessemail.com/blog/education-and-government-emailshttps://isbusinessemail.com/blog/education-and-government-emailsSchool, university and government addresses like .edu, .ac.uk and .gov are organizational, not personal. How they are classified and when it matters.Mon, 05 Oct 2026 00:00:00 GMTbusiness-emailbasicssaleslead-scoringhttps://isbusinessemail.com/blog/email-relay-addresseshttps://isbusinessemail.com/blog/email-relay-addressesRelay addresses on privaterelay.appleid.com, mozmail.com or duck.com forward to a hidden real inbox. How they work and how B2B sign-ups should handle them.Mon, 05 Oct 2026 00:00:00 GMTsignupb2bpolicydisposable-emailhttps://isbusinessemail.com/blog/email-typo-domainshttps://isbusinessemail.com/blog/email-typo-domainsEmail typo detection compares the domain with popular providers and offers a fix, like gmial.com to gmail.com. How it works, what typos cost, how to show it.Mon, 05 Oct 2026 00:00:00 GMTsignupfree-emailengineeringapihttps://isbusinessemail.com/blog/free-trial-abuse-email-signalshttps://isbusinessemail.com/blog/free-trial-abuse-email-signalsStop repeat free-trial sign-ups with email signals: disposable and relay inboxes, +tag and Gmail-dot variants, typo domains, new domains and a blocklist.Mon, 05 Oct 2026 00:00:00 GMTfraudsignupdisposable-emailpolicyhttps://isbusinessemail.com/blog/lookalike-and-punycode-domainshttps://isbusinessemail.com/blog/lookalike-and-punycode-domainsLookalike domains imitate gmail.com or paypal.com with Cyrillic letters, digits or rn for m. How punycode exposes them and how isBusinessEmail flags them.Mon, 05 Oct 2026 00:00:00 GMTfraudsignupdnsengineeringhttps://isbusinessemail.com/blog/plus-addressing-signup-dedupehttps://isbusinessemail.com/blog/plus-addressing-signup-dedupePlus addressing sends jane+news@acme.io to jane@acme.io, and Gmail ignores dots. How to deduplicate sign-ups with a key, without blocking anyone.Mon, 05 Oct 2026 00:00:00 GMTsignupfraudengineeringapihttps://isbusinessemail.com/blog/role-based-email-addresseshttps://isbusinessemail.com/blog/role-based-email-addressesRole-based email addresses like info@ and sales@ belong to a team, not a person. When to allow, review or block them at sign-up, in marketing and in sales.Mon, 05 Oct 2026 00:00:00 GMTsignupb2bpolicylead-scoringhttps://isbusinessemail.com/blog/shared-inboxes-and-google-groupshttps://isbusinessemail.com/blog/shared-inboxes-and-google-groupsA shared inbox is one mailbox a team answers from; a group forwards to many members. Why DNS can't tell them apart, and what the address name can.Mon, 05 Oct 2026 00:00:00 GMTbusiness-emailmicrosoft-365google-workspaceapihttps://isbusinessemail.com/blog/business-email-vs-personal-emailhttps://isbusinessemail.com/blog/business-email-vs-personal-emailBusiness email vs personal email: how they differ in ownership, security, offboarding, deliverability, cost and integrations, and when each is fine.Sun, 04 Oct 2026 00:00:00 GMTbusiness-emailbasicsb2bhttps://isbusinessemail.com/blog/check-business-email-in-codehttps://isbusinessemail.com/blog/check-business-email-in-codeCheck for a business email in JavaScript, Python and PHP: a free-provider list plus MX lookup you can run today, its pitfalls, and calling an API safely.Sun, 04 Oct 2026 00:00:00 GMTengineeringapisignuphttps://isbusinessemail.com/blog/email-verification-vs-classificationhttps://isbusinessemail.com/blog/email-verification-vs-classificationEmail verification vs email classification: one checks whether an address can receive mail, the other what kind of address it is. When you need both.Sun, 04 Oct 2026 00:00:00 GMTverificationsignupengineeringhttps://isbusinessemail.com/blog/find-a-business-email-addresshttps://isbusinessemail.com/blog/find-a-business-email-addressHow to find someone's business email address: company pages, email patterns, search operators and finder tools, then how to check it before you send.Sun, 04 Oct 2026 00:00:00 GMTsalesb2bbusiness-emailhttps://isbusinessemail.com/blog/free-email-providershttps://isbusinessemail.com/blog/free-email-providersA list of free email providers worldwide, from Gmail and Outlook to GMX, Yandex, QQ and Naver, plus ISP and privacy mailboxes, and what counts as personal.Sun, 04 Oct 2026 00:00:00 GMTfree-emaillistsbasicshttps://isbusinessemail.com/blog/how-to-tell-if-an-email-is-a-business-emailhttps://isbusinessemail.com/blog/how-to-tell-if-an-email-is-a-business-emailHow to tell if an email is a business email: read the domain, compare it with free provider lists, look up MX records and rule out disposable addresses.Sun, 04 Oct 2026 00:00:00 GMTbusiness-emailbasicsdnsmxhttps://isbusinessemail.com/blog/lead-scoring-by-email-domainhttps://isbusinessemail.com/blog/lead-scoring-by-email-domainLead scoring by email domain: why the domain is a strong signal, an example scoring model, routing to sales, CRM enrichment, pitfalls and measuring it.Sun, 04 Oct 2026 00:00:00 GMTsaleslead-scoringb2bhttps://isbusinessemail.com/blog/require-work-email-at-signuphttps://isbusinessemail.com/blog/require-work-email-at-signupHow to require a work email at sign-up: choose block, review or allow per category, write error messages that work, fix typos, plan exceptions, fail open.Sun, 04 Oct 2026 00:00:00 GMTsignupb2bpolicyhttps://isbusinessemail.com/blog/what-is-a-business-emailhttps://isbusinessemail.com/blog/what-is-a-business-emailA business email is an address on an organization's own domain, like jane@acme.io, not a shared one like gmail.com. Definition, examples and edge cases.Sun, 04 Oct 2026 00:00:00 GMTbusiness-emailbasicsb2bhttps://isbusinessemail.com/blog/which-email-provider-does-a-company-usehttps://isbusinessemail.com/blog/which-email-provider-does-a-company-useHow to find out which email provider a company uses: read its MX records, see past security gateways, then check SPF, DKIM and Microsoft 365 tenant data.Sun, 04 Oct 2026 00:00:00 GMTgoogle-workspacemicrosoft-365dnsmxhttps://isbusinessemail.com/blog/why-we-built-isbusinessemailhttps://isbusinessemail.com/blog/why-we-built-isbusinessemailPersonal-email signups kept stalling our B2B onboarding at the integration step. Here's the internal check we built, and why we made it a free API.Sun, 04 Oct 2026 00:00:00 GMTstoryb2bonboardinggoogle-workspacemicrosoft-365https://isbusinessemail.com/blog/google-workspace-vs-gmail-dnshttps://isbusinessemail.com/blog/google-workspace-vs-gmail-dnsHow to tell a Google Workspace domain from consumer Gmail using MX, DKIM and SPF records, where DNS misleads you, and the hd claim at sign-in.Thu, 01 Oct 2026 00:00:00 GMTdnsgoogle-workspacegmailmxengineeringhttps://isbusinessemail.com/blog/microsoft-365-tenant-vs-outlook-comhttps://isbusinessemail.com/blog/microsoft-365-tenant-vs-outlook-comMicrosoft 365 work accounts vs Outlook.com accounts: admin consent, SharePoint, OneDrive for Business, Teams, and finding a tenant before sign-in.Tue, 29 Sep 2026 00:00:00 GMTmicrosoft-365entra-idgraphonboardingengineeringhttps://isbusinessemail.com/blog/should-b2b-saas-block-free-email-signupshttps://isbusinessemail.com/blog/should-b2b-saas-block-free-email-signupsThe trade-offs of blocking Gmail and Outlook signups on a B2B product, the middle paths that keep good users, and how to decide with your own data.Sat, 26 Sep 2026 00:00:00 GMTb2bsignupgrowthproductpolicyhttps://isbusinessemail.com/blog/disposable-email-problemhttps://isbusinessemail.com/blog/disposable-email-problemWhy disposable email lists always lag behind, how throwaway services evade them, and the DNS and domain signals that catch what lists miss.Wed, 23 Sep 2026 00:00:00 GMTdisposable-emailfraudsignupdnsengineeringhttps://isbusinessemail.com/blog/detecting-business-emails-with-mx-recordshttps://isbusinessemail.com/blog/detecting-business-emails-with-mx-recordsWhat MX records reveal about an email domain (Workspace, Microsoft 365, gateways, hosting, forwarding), what they can't tell you, and pitfalls in code.Sun, 20 Sep 2026 00:00:00 GMTdnsmxemailengineeringb2b