https://pingutil.com/blog Guides on disposable email, signup fraud, business email detection and lead enrichment. en https://pingutil.com/blog/react-signup-form-email-feedback https://pingutil.com/blog/react-signup-form-email-feedback Wed, 07 Oct 2026 12:00:00 GMT Tutorials Check signup emails on blur in React 19: catch typos, disposable domains and role addresses with clear messages, a backend proxy and no blocking on failures. https://pingutil.com/blog/n8n-signup-classification-workflow https://pingutil.com/blog/n8n-signup-classification-workflow Mon, 05 Oct 2026 12:00:00 GMT Tutorials Build an n8n workflow that classifies each new signup's email as company, webmail, disposable or role-based and routes it, plus a deduped nightly batch. https://pingutil.com/blog/newsletter-list-cleaning https://pingutil.com/blog/newsletter-list-cleaning Thu, 01 Oct 2026 12:00:00 GMT Email validation What to remove from a newsletter list before a send: disposable and dead domains, provider typos, system addresses and sometimes role addresses. With a script. https://pingutil.com/blog/hubspot-contact-enrichment-webhook https://pingutil.com/blog/hubspot-contact-enrichment-webhook Mon, 28 Sep 2026 12:00:00 GMT Tutorials Use a HubSpot workflow's Send a webhook action to classify each new contact's email domain and write category, spam verdict and company fields to the record. https://pingutil.com/blog/card-testing-fake-accounts-email-signals https://pingutil.com/blog/card-testing-fake-accounts-email-signals Wed, 23 Sep 2026 12:00:00 GMT Disposable email Card testing is stopped mainly by payment-side controls: rate limits, CAPTCHA, Radar-style rules and 3DS. Email signals help with the fake accounts around it. https://pingutil.com/blog/clean-email-list-csv-script https://pingutil.com/blog/clean-email-list-csv-script Mon, 21 Sep 2026 12:00:00 GMT Tutorials A dependency-free Python script that dedupes a CSV of emails, classifies each domain, drops disposable and invalid addresses, and respects API rate limits. https://pingutil.com/blog/free-domain-intelligence-api https://pingutil.com/blog/free-domain-intelligence-api Thu, 17 Sep 2026 12:00:00 GMT Company enrichment What a free domain intelligence API should return, exactly what pingutil gives for free (fields and rate limits), what it doesn't do, and how free tiers compare. https://pingutil.com/blog/google-sheets-email-domain-lookup https://pingutil.com/blog/google-sheets-email-domain-lookup Mon, 14 Sep 2026 12:00:00 GMT Tutorials An Apps Script that tags every email in a Google Sheet as company, free, disposable, ISP or education, with throttling, domain dedupe and a safely stored key. https://pingutil.com/blog/exclude-fake-signups-from-analytics https://pingutil.com/blog/exclude-fake-signups-from-analytics Wed, 09 Sep 2026 12:00:00 GMT Disposable email Tag every signup as real, suspect, fake or internal when the account is created, then filter on that tag in PostHog, Mixpanel, Amplitude or plain SQL. https://pingutil.com/blog/auth0-pre-registration-email-check https://pingutil.com/blog/auth0-pre-registration-email-check Mon, 07 Sep 2026 12:00:00 GMT Tutorials Reject disposable and machine-generated signup emails in an Auth0 pre-user-registration Action, with secrets, a timeout, 429 backoff and fail-open logic. https://pingutil.com/blog/personalize-onboarding-from-email-domain https://pingutil.com/blog/personalize-onboarding-from-email-domain Tue, 01 Sep 2026 12:00:00 GMT Business email Branch onboarding on the signup email domain: team setup for company addresses, a solo flow for Gmail, an education plan for .edu. Code, UX copy and privacy rules. https://pingutil.com/blog/supabase-auth-block-disposable-emails https://pingutil.com/blog/supabase-auth-block-disposable-emails Fri, 28 Aug 2026 12:00:00 GMT Tutorials Use Supabase's Before User Created hook and an Edge Function to reject disposable and machine-generated emails at signup, with timeouts and fail-open handling. https://pingutil.com/blog/b2b-lead-scoring-email-domain https://pingutil.com/blog/b2b-lead-scoring-email-domain Thu, 27 Aug 2026 12:00:00 GMT Company enrichment A transparent points-based lead scoring model from email category, company size, industry and email signals, with starting weights and a calibration method. https://pingutil.com/blog/cloudflare-workers-email-validation https://pingutil.com/blog/cloudflare-workers-email-validation Mon, 24 Aug 2026 12:00:00 GMT Tutorials Screen signup emails in a Cloudflare Worker before they reach your origin: secrets, timeouts, 429 backoff and fail-open forwarding, with complete code. https://pingutil.com/blog/filter-fake-form-leads-webhook https://pingutil.com/blog/filter-fake-form-leads-webhook Tue, 18 Aug 2026 12:00:00 GMT Company enrichment Put a small webhook between Tally or Typeform and your CRM: verify the signature, classify the submitter's email, and route real leads to the CRM and junk to review. https://pingutil.com/blog/nextjs-signup-email-validation https://pingutil.com/blog/nextjs-signup-email-validation Mon, 17 Aug 2026 12:00:00 GMT Tutorials Check signup emails for disposable and machine-generated addresses inside a Next.js server action, with timeouts, 429 backoff and a clear fail-open policy. https://pingutil.com/blog/authjs-signin-callback-email-check https://pingutil.com/blog/authjs-signin-callback-email-check Tue, 11 Aug 2026 12:00:00 GMT Tutorials Use the Auth.js v5 signIn callback to block disposable and machine-generated emails for magic-link and OAuth sign-ins, with caching and fail-open handling. https://pingutil.com/blog/domain-lookup-api-quickstart https://pingutil.com/blog/domain-lookup-api-quickstart Mon, 10 Aug 2026 12:00:00 GMT Tutorials Call the pingutil domain lookup API from curl, JavaScript, Python and Go, with timeouts, 429 handling and the fields you should actually read. https://pingutil.com/blog/firebase-auth-block-disposable-emails https://pingutil.com/blog/firebase-auth-block-disposable-emails Mon, 03 Aug 2026 12:00:00 GMT Tutorials Reject disposable and machine-generated emails in Firebase Auth with a beforeUserCreated blocking function: setup requirements, full code, timeouts and fail-open. https://pingutil.com/blog/email-risk-score-free-signals https://pingutil.com/blog/email-risk-score-free-signals Thu, 30 Jul 2026 12:00:00 GMT Email validation A practical email risk score for signups: which free signals to use, hard rules vs points, score bands, and how to calibrate it against your own abuse data. https://pingutil.com/blog/go-email-domain-validation https://pingutil.com/blog/go-email-domain-validation Tue, 28 Jul 2026 12:00:00 GMT Tutorials A Go signup check with net/http, context timeouts, typed structs, an ICANN-only eTLD+1 helper built on x/net/publicsuffix, a TTL cache and fail-open 429 handling. https://pingutil.com/blog/domains-without-websites https://pingutil.com/blog/domains-without-websites Mon, 27 Jul 2026 12:00:00 GMT Email validation A signup domain that receives mail but has no website is a useful fraud signal, not a verdict. What DNS shows, the innocent cases, and how to score it. https://pingutil.com/blog/rails-email-domain-validation https://pingutil.com/blog/rails-email-domain-validation Tue, 21 Jul 2026 12:00:00 GMT Tutorials A Rails EachValidator that rejects disposable, machine-generated and optional free webmail emails, with Net::HTTP timeouts, Rails.cache and fail-open logic. https://pingutil.com/blog/catch-all-email-domains https://pingutil.com/blog/catch-all-email-domains Mon, 20 Jul 2026 12:00:00 GMT Email validation A catch-all domain accepts mail for any address, so verifiers can't confirm a mailbox. How detection works, why it's common in B2B, and how to treat it. https://pingutil.com/blog/laravel-disposable-email-validation https://pingutil.com/blog/laravel-disposable-email-validation Mon, 13 Jul 2026 12:00:00 GMT Tutorials A Laravel ValidationRule that rejects disposable, machine-generated and (optionally) free webmail addresses, using the Http facade with timeouts, retry and caching. https://pingutil.com/blog/email-normalization-gmail-dots-plus https://pingutil.com/blog/email-normalization-gmail-dots-plus Wed, 08 Jul 2026 12:00:00 GMT Email validation Why jane.doe+trial2@gmail.com and janedoe@googlemail.com are one inbox, and how to build a canonical email key that catches duplicates without breaking login. https://pingutil.com/blog/wordpress-block-fake-registrations https://pingutil.com/blog/wordpress-block-fake-registrations Mon, 06 Jul 2026 12:00:00 GMT Tutorials Block disposable and machine-generated emails at WordPress and WooCommerce registration with the registration_errors filter, a short timeout and fail-open logic. https://pingutil.com/blog/smtp-email-verification-limits https://pingutil.com/blog/smtp-email-verification-limits Thu, 02 Jul 2026 12:00:00 GMT Email validation What an SMTP mailbox probe really tests, the six ways its answers mislead you (VRFY, catch-all, greylisting, port 25 blocks), and what to use instead. https://pingutil.com/blog/is-gmail-a-business-email https://pingutil.com/blog/is-gmail-a-business-email Mon, 29 Jun 2026 12:00:00 GMT Business email No: @gmail.com is free personal webmail, even when a business uses it. Google Workspace on a custom domain is business. How to tell them apart in code. https://pingutil.com/blog/idn-punycode-email-domains https://pingutil.com/blog/idn-punycode-email-domains Thu, 25 Jun 2026 12:00:00 GMT Email validation Handle addresses like jane@bücher.de: convert the domain to punycode with UTS 46, leave the local part alone, and avoid the traps that split one domain in two. https://pingutil.com/blog/check-if-email-is-disposable https://pingutil.com/blog/check-if-email-is-disposable Mon, 22 Jun 2026 12:00:00 GMT Disposable email Check if an email is disposable by hand (public blocklist, MX lookup, a quick search) or in code with a list or an API. Includes a short checklist. https://pingutil.com/blog/dns-over-https-domain-checks https://pingutil.com/blog/dns-over-https-domain-checks Fri, 19 Jun 2026 12:00:00 GMT Email validation Run MX, A and AAAA lookups from edge functions and serverless runtimes with the Cloudflare and Google DoH JSON APIs: request format, status codes and gotchas. https://pingutil.com/blog/email-domain-intelligence-glossary https://pingutil.com/blog/email-domain-intelligence-glossary Mon, 15 Jun 2026 12:00:00 GMT Business email Plain definitions of 40 email and domain intelligence terms, from catch-all and null MX to eTLD+1, RDAP, SPF and DMARC, with links to deeper guides. https://pingutil.com/blog/check-mx-records-email-domain https://pingutil.com/blog/check-mx-records-email-domain Wed, 10 Jun 2026 12:00:00 GMT Email validation How to tell from DNS whether a domain accepts mail: MX lookups, the implicit MX fallback, null MX, and which DNS errors should never block a signup. https://pingutil.com/blog/llm-lead-qualification-deterministic-data https://pingutil.com/blog/llm-lead-qualification-deterministic-data Mon, 08 Jun 2026 12:00:00 GMT Company enrichment Which lead qualification steps an LLM is good at, which ones a deterministic lookup should own, and a pipeline that puts each in the right place. https://pingutil.com/blog/email-regex-is-not-enough https://pingutil.com/blog/email-regex-is-not-enough Thu, 04 Jun 2026 12:00:00 GMT Email validation A regex can only tell you an email address is shaped right. What to match, what to deliberately reject, and the checks a pattern can never replace. https://pingutil.com/blog/ai-agent-email-lookup-tool https://pingutil.com/blog/ai-agent-email-lookup-tool Mon, 01 Jun 2026 12:00:00 GMT Tutorials Tool definitions for Anthropic tool use, OpenAI function calling and MCP that let an LLM agent classify emails and domains with a real API, key kept server-side. https://pingutil.com/blog/email-validation-vs-verification https://pingutil.com/blog/email-validation-vs-verification Tue, 26 May 2026 12:00:00 GMT Email validation Validation checks that an address could work. Verification proves someone receives mail there. What each layer catches, misses, and where it belongs. https://pingutil.com/blog/spf-dmarc-domain-legitimacy https://pingutil.com/blog/spf-dmarc-domain-legitimacy Fri, 22 May 2026 12:00:00 GMT Email validation SPF and DMARC show whether a domain's owner set up outbound mail authentication. How to look them up over DNS, what they prove, and what they don't. https://pingutil.com/blog/detect-teammates-same-company https://pingutil.com/blog/detect-teammates-same-company Tue, 19 May 2026 12:00:00 GMT Company enrichment Detect teammates who sign up separately: group signups by registrable domain, skip webmail and schools, then send a team invite or a sales alert. https://pingutil.com/blog/domain-age-signup-risk https://pingutil.com/blog/domain-age-signup-risk Mon, 18 May 2026 12:00:00 GMT Disposable email How to check a signup domain's registration age with RDAP, when a young domain means risk, the innocent cases, and how to combine it with a domain lookup. https://pingutil.com/blog/etld-plus-one-explained https://pingutil.com/blog/etld-plus-one-explained Wed, 13 May 2026 12:00:00 GMT Company enrichment What eTLD+1 means, how the Public Suffix List defines it, why splitting on dots breaks on bbc.co.uk, and how to compute it in JavaScript, Python and Go. https://pingutil.com/blog/rdap-vs-whois-domain-lookup https://pingutil.com/blog/rdap-vs-whois-domain-lookup Fri, 08 May 2026 12:00:00 GMT Email validation RDAP replaced WHOIS for generic TLDs in 2025. How the two protocols differ, how to query RDAP in code, and where you still need WHOIS for country-code domains. https://pingutil.com/blog/caching-domain-lookups https://pingutil.com/blog/caching-domain-lookups Tue, 05 May 2026 12:00:00 GMT Company enrichment How to cache email and domain lookup results: what to key on, which fields can share a cache entry, TTLs per data type, stale-on-error, and when to force a refresh. https://pingutil.com/blog/email-verification-vs-domain-classification https://pingutil.com/blog/email-verification-vs-domain-classification Mon, 04 May 2026 12:00:00 GMT Email validation Verification services check if a mailbox will accept mail. Classification APIs tell you what kind of address it is. Which job needs which, and when to use both. https://pingutil.com/blog/llm-company-enrichment-accuracy https://pingutil.com/blog/llm-company-enrichment-accuracy Mon, 27 Apr 2026 12:00:00 GMT Company enrichment Where AI company enrichment is reliable, where it fails (invented funding, stale HQs, the wrong company), and the guardrails that make it safe to use. https://pingutil.com/blog/free-domain-lookup-tools https://pingutil.com/blog/free-domain-lookup-tools Fri, 24 Apr 2026 12:00:00 GMT Company enrichment Free domain lookup tools grouped by the question they answer: registration (RDAP, WHOIS), DNS, domain type and company data, with commands you can run now. https://pingutil.com/blog/crm-data-hygiene-email-domains https://pingutil.com/blog/crm-data-hygiene-email-domains Wed, 22 Apr 2026 12:00:00 GMT Company enrichment Clean up a CRM by email domain: normalize company domains, merge duplicate accounts, separate personal and disposable contacts, and keep it clean. https://pingutil.com/blog/free-disposable-email-detection-tools https://pingutil.com/blog/free-disposable-email-detection-tools Fri, 17 Apr 2026 12:00:00 GMT Disposable email Free disposable email detection tools by type: open lists, libraries, keyless endpoints, free APIs and web checkers, with list sizes and the trade-offs of each. https://pingutil.com/blog/route-leads-by-company-size https://pingutil.com/blog/route-leads-by-company-size Tue, 14 Apr 2026 12:00:00 GMT Company enrichment Build lead routing rules on enriched company size, industry and country: segment buckets, an ordered rule table, confidence gates and a triage queue for unknowns. https://pingutil.com/blog/best-free-email-validation-apis https://pingutil.com/blog/best-free-email-validation-apis Thu, 09 Apr 2026 12:00:00 GMT Email validation Free tiers of ZeroBounce, Abstract, Hunter, MailboxValidator, Emailable, Kickbox and pingutil compared: quotas, resets, SMTP checks and where each fits. https://pingutil.com/blog/enrich-leads-from-email-domain https://pingutil.com/blog/enrich-leads-from-email-domain Mon, 06 Apr 2026 12:00:00 GMT Company enrichment Design a lead enrichment step that starts from a work email: gate by domain type, enrich async, record provenance, never overwrite human input. https://pingutil.com/blog/clearbit-alternatives https://pingutil.com/blog/clearbit-alternatives Thu, 02 Apr 2026 12:00:00 GMT Company enrichment What changed at Clearbit after HubSpot bought it, which features are gone, and a replacement for each one: logos, enrichment, form shortening and signup screening. https://pingutil.com/blog/free-company-enrichment-api https://pingutil.com/blog/free-company-enrichment-api Tue, 31 Mar 2026 12:00:00 GMT Company enrichment Free company enrichment comes in three forms: capped tiers of paid databases, LLM-generated profiles, and DIY scraping. What each returns, and how to test them. https://pingutil.com/blog/what-is-domain-intelligence https://pingutil.com/blog/what-is-domain-intelligence Wed, 25 Mar 2026 12:00:00 GMT Company enrichment Domain intelligence is everything you can learn about a domain name: what kind of domain it is, whether it works, who registered it and which company is behind it. https://pingutil.com/blog/government-email-domains https://pingutil.com/blog/government-email-domains Mon, 23 Mar 2026 12:00:00 GMT Business email A country-by-country guide to government email domains: what .gov, gov.uk and gouv.fr rules catch, what they miss (gc.ca, bund.de, go.jp), with detection code. https://pingutil.com/blog/verify-student-email-address https://pingutil.com/blog/verify-student-email-address Wed, 18 Mar 2026 12:00:00 GMT Business email How to check if an email belongs to a university or school: TLD rules that work, the countries they miss, a university domain list, and a verification flow. https://pingutil.com/blog/isp-email-domains https://pingutil.com/blog/isp-email-domains Mon, 16 Mar 2026 12:00:00 GMT Business email comcast.net, btinternet.com and orange.fr are consumer ISP mailboxes. Why they break lead enrichment and routing, which domains to list, and how to treat them. https://pingutil.com/blog/role-based-email-addresses https://pingutil.com/blog/role-based-email-addresses Fri, 13 Mar 2026 12:00:00 GMT Business email Role-based addresses like info@ and support@ are shared inboxes, not people. When to accept, flag or reject them, and how to detect them without false hits. https://pingutil.com/blog/find-company-from-email-address https://pingutil.com/blog/find-company-from-email-address Mon, 09 Mar 2026 12:00:00 GMT Business email Turn an email address into a company name: normalize the domain, discard webmail and ISP domains, then resolve the rest from its website or an enrichment API. https://pingutil.com/blog/require-work-email-b2b-signup https://pingutil.com/blog/require-work-email-b2b-signup Thu, 05 Mar 2026 12:00:00 GMT Business email When a work-email-only signup helps a B2B funnel, when it quietly costs you customers, and how to ask for a work email without rejecting anyone. https://pingutil.com/blog/free-email-provider-domains https://pingutil.com/blog/free-email-provider-domains Mon, 02 Mar 2026 12:00:00 GMT Business email The webmail domains worth listing, grouped by provider and region, why 30,000-domain lists answer a different question, and how to tune a list to your users. https://pingutil.com/blog/business-email-vs-personal-email https://pingutil.com/blog/business-email-vs-personal-email Thu, 26 Feb 2026 12:00:00 GMT Business email Classify an email as business or personal: reduce to the registrable domain, check provider lists, then use MX records to catch personal custom domains. https://pingutil.com/blog/block-or-flag-disposable-emails https://pingutil.com/blog/block-or-flag-disposable-emails Mon, 23 Feb 2026 12:00:00 GMT Disposable email A decision framework for disposable email at signup: which surfaces deserve a hard block, when to flag instead, and what a flag should do to the account. https://pingutil.com/blog/disposable-email-checker-api-options https://pingutil.com/blog/disposable-email-checker-api-options Tue, 17 Feb 2026 12:00:00 GMT Disposable email Open blocklists, free hosted endpoints, paid verification APIs and domain intelligence APIs compared on cost, latency, freshness and failure modes. https://pingutil.com/blog/referral-and-promo-abuse-email-signals https://pingutil.com/blog/referral-and-promo-abuse-email-signals Mon, 16 Feb 2026 12:00:00 GMT Disposable email Referral abuse is one person posing as many. The email signals that link those fake referees together, with code that scores a referrer before you pay out. https://pingutil.com/blog/detect-random-email-addresses https://pingutil.com/blog/detect-random-email-addresses Wed, 11 Feb 2026 12:00:00 GMT Disposable email How to spot bot-made addresses like xk7qmz2p@gmail.com from the local part alone: the features that work, a runnable scorer, and where it flags real people. https://pingutil.com/blog/email-relay-services-vs-disposable https://pingutil.com/blog/email-relay-services-vs-disposable Fri, 06 Feb 2026 12:00:00 GMT Disposable email Relay addresses look random but forward to a real, long-lived inbox. Why they differ from disposable email, why filters misfire on them, and how to allow them. https://pingutil.com/blog/fake-signups-saas https://pingutil.com/blog/fake-signups-saas Wed, 04 Feb 2026 12:00:00 GMT Disposable email Fake SaaS signups come from five different sources, and each needs a different filter. How to tell which one you have, and what to put in front of each. https://pingutil.com/blog/stop-free-trial-abuse https://pingutil.com/blog/stop-free-trial-abuse Fri, 30 Jan 2026 12:00:00 GMT Disposable email A practical playbook for SaaS founders: screen signup emails, dedupe identities and gate trial value in steps, so abusers stall and real users never notice. https://pingutil.com/blog/disposable-email-blocklists-go-stale https://pingutil.com/blog/disposable-email-blocklists-go-stale Mon, 26 Jan 2026 12:00:00 GMT Disposable email The open disposable domain list doubled in a year. Why vendored copies decay, how lists also gather bad entries, and a safe update process with code. https://pingutil.com/blog/block-disposable-emails-python https://pingutil.com/blog/block-disposable-emails-python Fri, 23 Jan 2026 12:00:00 GMT Disposable email Block disposable email signups in Django and FastAPI with one shared validator, the PyPI blocklist package, offline PSL matching and a fail-open API option. https://pingutil.com/blog/block-disposable-emails-nodejs https://pingutil.com/blog/block-disposable-emails-nodejs Wed, 21 Jan 2026 12:00:00 GMT Disposable email Express 5 middleware that blocks disposable email signups using a self-refreshing open blocklist or a single API call, with tests and fail-open handling. https://pingutil.com/blog/how-to-detect-disposable-email-addresses https://pingutil.com/blog/how-to-detect-disposable-email-addresses Mon, 19 Jan 2026 12:00:00 GMT Disposable email Four layered checks that catch disposable email at signup: domain normalization, an updating blocklist, MX fingerprinting and DNS signals, with working code. https://pingutil.com/blog/what-is-a-disposable-email-address https://pingutil.com/blog/what-is-a-disposable-email-address Tue, 13 Jan 2026 12:00:00 GMT Disposable email What disposable email addresses are, how services like Mailinator work, who uses them, and a simple rule for deciding whether your product should block them.