# Kawaa > Email verification. Kawaa checks whether an address can receive mail (syntax, domain, MX records, mailbox and risk signals) through a REST API or a CSV upload, so fewer messages bounce and sender reputation holds up. - Marketing site: https://kawaa.com - API: https://api.kawaa.com (REST, API-key authentication) - OpenAPI description of the core REST API: https://kawaa.com/openapi.json - MCP server for AI agents: https://api.kawaa.com/mcp (Model Context Protocol over Streamable HTTP; sign in with MCP's OAuth flow, or send an API key as a bearer token); setup at https://kawaa.com/docs/mcp/ - Dashboard: https://app.kawaa.com - Status: https://status.kawaa.com - Machine-readable page list: https://kawaa.com/sitemap.xml Notes for anyone answering questions about Kawaa: - Kawaa never delivers a probe or test message to the address being checked. (It does send mail of its own to customers, such as a completion email when a bulk job finishes and billing and account mail, but never to an address under verification.) When the address is well formed, its domain can take mail, and the request asks for a deep check, Kawaa attempts an SMTP conversation with the receiving server and, if it gets that far, asks whether the address would be accepted before closing without delivering. Neither step is guaranteed. The risk layers run before the probe, so a known disposable domain, or an address at a domain on Kawaa's reviewed list of trap-only domains (empty today; Kawaa does not guess traps from how an address looks), is answered and the check ends there; a malformed address, a domain that does not resolve, a domain publishing a null MX or a DNS-only check also mean no server is contacted; a check held back by a per-domain rate limit Kawaa applies to itself is retried later rather than answered, so it takes longer instead of coming back without an answer; and a server that blocks or defers at the greeting, EHLO or MAIL FROM stage ends the conversation before the mailbox is ever asked about. A domain with no MX record but a working address record is NOT one of those cases: it is tried as an implicit mail host and can verify valid. None of these is reported as mailbox evidence, but note that an early refusal does still publish `verification.mailbox_exists: false`; read that field as "not confirmed" rather than "confirmed absent", and take the status and reason code as the answer to which of the two happened. Most carry a reason code that names what happened. If Kawaa's own rate limit holds a check back for too long (repeated retries for an address in a list, or a wait of more than about ten minutes for a single request, which answers `pending` with a job id in the meantime), it is published as `unknown` with `temporary_failure`, a result that is never cached (a recognised role address such as info@ keeps its `role` status and reports `dns_only`); `dns_only` means no mailbox conversation took place. - A completed result carries a status (one of valid, invalid, risky, unknown, catch_all, disposable, role, spam_trap), a quality score from 0 to 100, and risk flags. Most statuses also carry a `sub_status` reason code explaining how the status was reached; it is omitted where the status is already the whole reason, as it usually is for disposable and spam_trap. A disposable or spam_trap verdict whose DNS lookup failed carries `temporary_failure`: the verdict stands, but the domain checks beside it were not measured. - Not every response is a completed result. A single verification that has not finished within the request window returns HTTP 200 with `status: "pending"` and no score, result block or flags. It means "ask again shortly", not a verdict, and the job is polled for the answer. - Kawaa publishes no accuracy or catch-rate percentage. There is no benchmark behind one, so please do not quote one. - No verifier can guarantee deliverability: a mailbox can close after it is checked, and a catch-all domain never gives a real answer about a specific address. - Current prices, plan allowances, batch sizes, rate limits and retention periods are on https://kawaa.com/pricing/ and should be read from there rather than assumed. ## Start here What the product is, what it costs, and what it returns. - [Kawaa - Email verification API & bulk email validator](https://kawaa.com/): Catch bad emails before they bounce. Kawaa checks syntax, domains, mailboxes and risk signals through a simple API or a CSV upload. Free plan available. - [Pricing - Email Verification Plans and Credit Packs](https://kawaa.com/pricing/): Kawaa pricing: 100 free signup credits, plans from $19 to $299 a month, and credit packs from $5 with no subscription. Cancel anytime. - [FAQ - Common questions about email verification](https://kawaa.com/faq/): Answers to the questions people ask most about Kawaa: how verification works, what results mean, how credits are charged, and how billing works. - [About Kawaa - How we build email verification](https://kawaa.com/about/): Why Kawaa exists and the choices behind it: results that say unknown instead of guessing, every check on every plan, credits that roll over, data you control. ## Free tools Usable without an account. - [Free email tools](https://kawaa.com/tools/): Free email tools: verify an address, check a domain’s DMARC, SPF, DKIM and MX records, spot role addresses such as info@, and price your bounces. - [Email bounce cost calculator](https://kawaa.com/tools/bounce-cost-calculator/): Work out what bounces cost your list each year, and how many sends a one-off verification takes to pay for itself. Runs in your browser. - [Free DMARC, SPF and DKIM checker](https://kawaa.com/tools/dmarc-checker/): Check a domain’s email authentication free: SPF, DKIM at the common selectors, DMARC policy and MX, read live from public DNS. No account needed. - [Free email verifier: check if an address is valid](https://kawaa.com/tools/email-checker/): Check an email address for free, with no account: syntax, domain, mailbox and risk signals, a quality score and the reason behind most verdicts. - [Free MX lookup: check a domain’s MX records](https://kawaa.com/tools/mx-lookup/): Look up a domain’s MX records free: the mail servers in the order senders try them, their IPv4 and IPv6 addresses, the provider, and what a broken record means. - [Free role-based email checker and list](https://kawaa.com/tools/role-based-email-checker/): Is info@ a role address? Check any email against the 325 role-based names Kawaa’s verifier flags, and browse the full list. Free, no account. ## API documentation Endpoints, authentication, errors, rate limits, webhooks and SDKs. - [API documentation](https://kawaa.com/docs/): Complete API documentation for Kawaa email verification. Learn how to integrate the REST API and the published Node.js and Python SDKs. - [Account & API keys | Kawaa Docs](https://kawaa.com/docs/api/account/): API reference for your Kawaa account: account info, credit balance and transactions, and creating, listing and revoking API keys. - [Activity data API | Kawaa Docs](https://kawaa.com/docs/api/activity/): API reference for activity data: the opens, clicks and activity score your tracking has recorded for an address or a domain. - [Batch & file verification API | Kawaa Docs](https://kawaa.com/docs/api/batch/): API reference for batch email verification and file uploads. Verify thousands of emails asynchronously. - [Deliverability API | Kawaa Docs](https://kawaa.com/docs/api/deliverability/): API reference for domain deliverability checks: run a check on a domain, list your check history, and fetch a single check. - [Verification API | Kawaa Docs](https://kawaa.com/docs/api/verification/): API reference for single email verification. Verify emails in real-time with detailed results. - [Webhooks API | Kawaa Docs](https://kawaa.com/docs/api/webhooks/): API reference for managing Kawaa webhooks programmatically: create, list, update, test and delete endpoints, and read their delivery logs. - [White-label sub-accounts API | Kawaa Docs](https://kawaa.com/docs/api/white-label/): API reference for creating white-label sub-accounts, allocating and reclaiming their credits, and resetting their API keys. - [Authentication | Kawaa Docs](https://kawaa.com/docs/authentication/): Authenticate with the Kawaa API using an API key, sent in the X-Api-Key header or as a Bearer token, and keep your keys secure. - [Error codes | Kawaa Docs](https://kawaa.com/docs/errors/): The API error codes an integration is most likely to meet, what each one means, and whether retrying can help. - [MCP server for AI agents | Kawaa Docs](https://kawaa.com/docs/mcp/): Connect Claude Code, Codex, Cursor CLI, Copilot CLI and other agents to Kawaa over the Model Context Protocol: one URL, sign in or use an API key, twelve tools. - [API playground | Kawaa Docs](https://kawaa.com/docs/playground/): Test the Kawaa API directly in your browser. Try email verification endpoints, see responses, and generate cURL commands. - [Quick start | Kawaa Docs](https://kawaa.com/docs/quickstart/): Verify your first email with the Kawaa API, handle pending results, and retry safely. - [Rate limits | Kawaa Docs](https://kawaa.com/docs/rate-limits/): The per-key and per-plan rate limits of the Kawaa API, the headers that report them, and how to back off when you receive a 429. - [Understanding results & provider limits | Kawaa Docs](https://kawaa.com/docs/results-provider-limits/): How to interpret Kawaa verification statuses, quality scores, catch-all domains, and mailbox-provider limitations. - [SDKs & libraries | Kawaa Docs](https://kawaa.com/docs/sdks/): Kawaa publishes Node.js and Python SDK packages. Go, Ruby, PHP, Java, C#, and Rust clients are not yet published; every language can call the REST API directly. - [Webhooks guide | Kawaa Docs](https://kawaa.com/docs/webhooks/): Receive an HTTP callback when a Kawaa verification job finishes: the events and payload, how to check the signature, and the retry policy. ## Comparisons Kawaa beside other verification services. - [Compare email verification services](https://kawaa.com/compare/): Side-by-side comparisons of Kawaa against other email verification services on pricing, features, integrations, and support. - [Bouncer alternative: Kawaa pricing and features compared](https://kawaa.com/compare/bouncer/): Looking for a Bouncer alternative? Compare Bouncer pricing and features with Kawaa, including where Bouncer is the better choice. - [Clearout alternative: Kawaa pricing and features compared](https://kawaa.com/compare/clearout/): Looking for a Clearout alternative? Compare Clearout pricing and features with Kawaa, including where Clearout is the better choice. - [DeBounce alternative: Kawaa pricing and features compared](https://kawaa.com/compare/debounce/): Looking for a DeBounce alternative? Compare DeBounce pricing and features with Kawaa, including where DeBounce is the better choice. - [Emailable alternative: Kawaa pricing and features compared](https://kawaa.com/compare/emailable/): Looking for an Emailable alternative? Compare Emailable pricing and features with Kawaa, including where Emailable is the better choice. - [EmailListVerify alternative: Kawaa pricing and features](https://kawaa.com/compare/emaillistverify/): Looking for an EmailListVerify alternative? Compare EmailListVerify pricing and features with Kawaa, including where EmailListVerify is the better choice. - [Hunter.io alternative: Kawaa pricing and features compared](https://kawaa.com/compare/hunter/): Looking for a Hunter.io alternative? Compare Hunter.io pricing and features with Kawaa, including where Hunter.io is the better choice. - [Kickbox alternative: Kawaa pricing and features compared](https://kawaa.com/compare/kickbox/): Looking for a Kickbox alternative? Compare Kickbox pricing and features with Kawaa, including where Kickbox is the better choice. - [MillionVerifier alternative: Kawaa pricing and features](https://kawaa.com/compare/millionverifier/): Looking for a MillionVerifier alternative? Compare MillionVerifier pricing and features with Kawaa, including where MillionVerifier is the better choice. - [NeverBounce alternative: Kawaa pricing and features compared](https://kawaa.com/compare/neverbounce/): Looking for a NeverBounce alternative? Compare NeverBounce pricing and features with Kawaa, including where NeverBounce is the better choice. - [Verifalia alternative: Kawaa pricing and features compared](https://kawaa.com/compare/verifalia/): Looking for a Verifalia alternative? Compare Verifalia pricing and features with Kawaa, including where Verifalia is the better choice. - [ZeroBounce alternative: Kawaa pricing and features compared](https://kawaa.com/compare/zerobounce/): Looking for a ZeroBounce alternative? Compare ZeroBounce pricing and features with Kawaa, including where ZeroBounce is the better choice. ## Use cases How different kinds of sender use verification. - [Use cases - Email verification for every team](https://kawaa.com/use-cases/): How marketers, developers, agencies, recruiters, ecommerce, and SaaS teams use Kawaa to cut bounces and protect sender reputation. - [For agencies - Email verification use cases](https://kawaa.com/use-cases/agencies/): Verify for several clients without mixing up their credits: Enterprise sub-accounts with their own allocations, and white-label settings. - [For developers - Email verification use cases](https://kawaa.com/use-cases/developers/): One REST endpoint returns a status, a sub-status, a 0–100 quality score and flags. Verify at sign-up, or submit a batch and get a webhook. - [For e-commerce - Email verification use cases](https://kawaa.com/use-cases/ecommerce/): Order confirmations, receipts and password resets all depend on the address a customer typed. Check it from your backend while they are still on the page. - [For marketers - Email verification use cases](https://kawaa.com/use-cases/marketers/): Upload a list and get a status, a quality score and the reason behind each flag, so removing an address is a decision you can explain. - [For recruiters - Email verification use cases](https://kawaa.com/use-cases/recruiters/): Verify a single address before a message or a whole sourcing list at once, and find a candidate’s work address from their name and company domain. - [For SaaS - Email verification use cases](https://kawaa.com/use-cases/saas/): Verify an address at sign-up, see whether it is disposable, role-based or likely mistyped, and decide with your own rules whether to let it in. ## Integrations Verification inside other tools, with setup guides. - [Integrations - Connect Kawaa to Your Stack](https://kawaa.com/integrations/): Connect Kawaa to the tools you already use. Browse available integrations, native API access, and webhook delivery. - [ActiveCampaign integration - Email verification](https://kawaa.com/integrations/activecampaign/): Verify ActiveCampaign contacts as they enter an automation, through a webhook action and an endpoint you control, and branch on the result. - [REST API integration - Email verification](https://kawaa.com/integrations/api/): Verify single emails or bulk lists with the Kawaa REST API, from the published Node.js and Python packages or plain HTTP in any language. - [HubSpot integration - Email verification](https://kawaa.com/integrations/hubspot/): Verify HubSpot contacts with the Kawaa REST API from a workflow, store the result in contact properties and leave invalid addresses out of your lists. - [Klaviyo integration - Email verification](https://kawaa.com/integrations/klaviyo/): Verify Klaviyo lists before a campaign: check an export in bulk with Kawaa, import the result as a profile property and segment on it. - [Mailchimp integration - Email verification](https://kawaa.com/integrations/mailchimp/): Verify a Mailchimp audience before you send: check an export in bulk with Kawaa, then tag or archive invalid addresses when you import it back. - [Make integration - Email verification](https://kawaa.com/integrations/make/): Verify emails in any Make scenario today with Make's HTTP module and the Kawaa API. A dedicated Kawaa app for Make is coming soon. - [n8n integration - Email verification](https://kawaa.com/integrations/n8n/): Verify email addresses inside n8n workflows with an HTTP Request node that calls the Kawaa API, then branch on the result with IF or Switch nodes. - [Salesforce integration - Email verification](https://kawaa.com/integrations/salesforce/): Verify Salesforce lead and contact emails with the Kawaa REST API from a Flow or your own middleware, and store the result in custom fields. - [Shopify integration - Email verification](https://kawaa.com/integrations/shopify/): Verify Shopify customer emails from your own server with the Kawaa REST API, and clean customer exports in bulk. Checkout validation is in development. - [Webhooks integration - Email verification](https://kawaa.com/integrations/webhooks/): Get an HTTP callback when a Kawaa verification or bulk job finishes, with signed payloads, retries on failure and delivery logs. - [WordPress integration - Email verification](https://kawaa.com/integrations/wordpress/): Download the Kawaa WordPress plugin to check email fields in Contact Form 7, WPForms, Gravity Forms, Elementor Pro forms and the WooCommerce classic checkout. - [Zapier integration - Email verification](https://kawaa.com/integrations/zapier/): Verify emails in your Zaps today with a Webhooks by Zapier step that calls the Kawaa API. A dedicated Kawaa app for Zapier is coming soon. ## Guides Long-form articles on deliverability and list hygiene. - [Blog - Email deliverability insights](https://kawaa.com/blog/): Expert insights on email verification, deliverability, and list hygiene. Learn how to reduce bounce rates, avoid spam traps, and improve sender reputation. - [Catch-all emails: How to verify unverifiable addresses](https://kawaa.com/blog/catch-all-emails-complete-guide/): Catch-all domains accept every address, so a mailbox check cannot tell a real one from a made-up one. Learn how detection works and how to weigh the risk. - [Guide articles - Email deliverability insights](https://kawaa.com/blog/category/guide/): Kawaa articles filed under Guide: email verification, deliverability, and list hygiene. - [Disposable email addresses: How to detect and prevent them](https://kawaa.com/blog/disposable-email-addresses-complete-guide/): Disposable emails inflate your list, skew your metrics and rarely convert. Learn how to detect temporary email addresses and protect your list quality. - [SPF, DKIM, and DMARC: Email authentication guide](https://kawaa.com/blog/email-authentication-spf-dkim-dmarc/): Set up SPF, DKIM and DMARC to protect your domain from spoofing and improve deliverability, with step-by-step setup instructions and troubleshooting. - [Email deliverability audit checklist for 2026](https://kawaa.com/blog/email-deliverability-audit-checklist/): An actionable checklist to audit your email deliverability, covering authentication, list hygiene, sender reputation, infrastructure and monitoring. - [Email sender reputation: How to protect your domain](https://kawaa.com/blog/email-sender-reputation-complete-guide/): Your sender reputation determines whether emails reach the inbox or spam folder. Learn how to monitor, protect, and improve your email reputation score. - [Why we don't publish an accuracy percentage](https://kawaa.com/blog/email-verification-accuracy-claims/): Why no email verifier can measure an accuracy percentage honestly, what to ask a vendor instead, and what Kawaa publishes in place of a number. - [Email warmup: How to build sender reputation from scratch](https://kawaa.com/blog/email-warmup-guide/): New domain or IP? Learn the exact process to warm up your email infrastructure, avoid spam filters, and build a strong sender reputation that lasts. - [Hard bounces vs soft bounces: Understanding email bounce types](https://kawaa.com/blog/hard-bounces-vs-soft-bounces/): Learn the difference between hard and soft bounces, what causes each type, and how to handle them to protect your sender reputation. - [How to reduce your email bounce rate](https://kawaa.com/blog/reduce-email-bounce-rate/): High bounce rates destroy sender reputation. Learn practical ways to find the cause and keep your bounce rate under 2%. - [Role-based addresses: Should you send to info@ and sales@?](https://kawaa.com/blog/role-based-email-addresses-guide/): Addresses like info@, sales@ and support@ look like valid targets but can hurt deliverability. Learn why they're risky and how to handle them. - [Spam traps explained: How to detect and avoid them](https://kawaa.com/blog/spam-traps-complete-guide/): A few spam trap hits can get your domain blacklisted. Understand the different types and how to protect your email program. - [The ultimate guide to email verification](https://kawaa.com/blog/ultimate-guide-email-verification/): Everything you need to know about email verification: how it works, why it matters, and how to choose the right solution for your business. ## Help articles Task-level answers about the product. - [Help center & support - Get help with email verification](https://kawaa.com/support/): Find answers to common questions, browse the Kawaa knowledge base, or contact the support team for help with API integration, billing and troubleshooting. - [Abuse email detection - Support](https://kawaa.com/support/abuse-detection/): Flag abuse and complaint contacts, such as abuse@ and legal@, and the complaint desks of listed anti-spam organizations before sending. - [API authentication - Support](https://kawaa.com/support/api-auth/): Authenticate API requests with your API key, sent in the X-Api-Key header or as a Bearer token in the Authorization header. - [Batch verification - Support](https://kawaa.com/support/api-batch/): Verify several email addresses in one API call with POST /v1/verify/batch, up to your account’s batch size, then fetch the results. - [Error codes - Support](https://kawaa.com/support/api-errors/): The HTTP status codes and error codes the Kawaa API returns, what each one means, and how to handle it. - [File upload verification - Support](https://kawaa.com/support/api-file/): Upload a CSV, TSV or TXT file containing email addresses for bulk verification. - [Rate limits - Support](https://kawaa.com/support/api-rate-limits/): API requests are limited per key and per plan. See the limit on each plan and how to handle a 429 response. - [Single email verification - Support](https://kawaa.com/support/api-single/): Verify one email address with POST /v1/verify: the request body, the options it accepts and the response you get back. - [Auto-clean lists - Support](https://kawaa.com/support/auto-clean-lists/): Recheck a completed list daily, weekly or monthly, and review refreshed results and run history. - [Cancellation policy - Support](https://kawaa.com/support/cancellation/): How to cancel your Kawaa subscription, what happens to your access, credits and data afterwards, how reactivation works, and our refund policy. - [Catch-all domains - Support](https://kawaa.com/support/catch-all/): Catch-all domains accept mail for any address, so a mailbox check cannot confirm one. How Kawaa reports them, and what to do with them. - [Common API errors - Support](https://kawaa.com/support/common-errors/): Quick fixes for the most common Kawaa API errors, 400, 401, 402, 403 and 429, with the cause of each and what to change. - [How credits work - Support](https://kawaa.com/support/credits/): A fresh verification costs one credit and a cached result half a credit. How credits are used, allocated and tracked, and what happens when you run out. - [Data enrichment (name and gender) - Support](https://kawaa.com/support/data-enrichment/): Add first and last names and a predicted gender, read from the address itself, to your verification results on the plans that include it. - [Disposable email detection - Support](https://kawaa.com/support/disposable/): Identify temporary, throwaway email addresses in your lists, see why they hurt engagement, and read how Kawaa flags them in a result. - [Data processing agreement - Support](https://kawaa.com/support/dpa/): What the Kawaa Data Processing Agreement covers, when you need one, and how it applies to the personal data you verify with us. - [DMARC/SPF/DKIM monitoring - Support](https://kawaa.com/support/email-auth-monitoring/): Monitor the SPF, DKIM and DMARC records on your domains that affect deliverability, and get an alert when something needs attention. - [Email warmup - Support](https://kawaa.com/support/email-warmup/): Gradually build sender reputation for a new domain or IP: what warmup is, why it matters, and the status of Kawaa warmup today. - [Failed and processing payments - Support](https://kawaa.com/support/failed-payments/): What happens to your plan, credits and API keys when a renewal payment is declined or a payment is still processing, and what to do. - [Creating your first API key - Support](https://kawaa.com/support/first-api-key/): API keys authenticate your requests to the Kawaa API. Here is how to create one in the dashboard, keep it safe and revoke it. - [Making your first verification - Support](https://kawaa.com/support/first-verification/): Verify your first email address with the Kawaa API, from curl or your own Node.js or Python code, or try one in the dashboard. - [GDPR compliance - Support](https://kawaa.com/support/gdpr/): Kawaa is built to support GDPR obligations with privacy controls, DPA coverage, and data subject request workflows. - [How email verification works - Support](https://kawaa.com/support/how-it-works/): Kawaa uses a multi-layer verification process with syntax, DNS/MX, risk, and AI-assisted signals. - [Invoices & receipts - Support](https://kawaa.com/support/invoices/): Find, download and open your Kawaa invoices and receipts, see what each one contains, and update your billing details. - [Country hint enrichment - Support](https://kawaa.com/support/location-enrichment/): Get a country-level hint from email domains when a reliable signal exists. - [Pricing plans - Support](https://kawaa.com/support/pricing/): Compare the Kawaa plans, from Free to Enterprise, with the credits and price of each, and see what every plan includes. - [Quick start guide - Support](https://kawaa.com/support/quick-start/): Create a free account, get an API key and verify your first address: getting started with Kawaa takes about five minutes. - [Rate limit exceeded - Support](https://kawaa.com/support/rate-limit-help/): How to handle a 429 rate limit response: the limits on each plan, how to back off and retry, and what to do if you need more. - [Data retention policy - Support](https://kawaa.com/support/retention/): How long Kawaa keeps verification results, uploaded files, account data and billing records, and how to delete data early. - [Role-based email detection - Support](https://kawaa.com/support/role-based/): Role-based addresses such as info@ and sales@ reach a function, not a person. Understand the risks and how Kawaa flags them. - [Data security practices - Support](https://kawaa.com/support/security/): How Kawaa protects your data: encryption in transit and at rest, access control, data handling, and how to report a security issue. - [Spam traps - Support](https://kawaa.com/support/spam-trap-detection/): What spam traps are, why they hurt your sender reputation, and what Kawaa can and cannot tell you about them. - [Verification statuses explained - Support](https://kawaa.com/support/statuses/): Every result carries one of eight statuses. Code that only handles four of them will fall through on real traffic. - [Verification timeouts - Support](https://kawaa.com/support/timeouts/): Why a verification can time out, the timeouts Kawaa applies to DNS and SMTP checks, and how to handle a timeout response. - [Unexpected results - Support](https://kawaa.com/support/unexpected-results/): What to do when a result is not what you expected: why a valid address can bounce, and why a working one can show invalid. - [Upgrading your plan - Support](https://kawaa.com/support/upgrade/): Upgrade your Kawaa plan from Settings → Billing, see what changes when you upgrade or downgrade, and find out about Enterprise plans. - [Understanding verification results - Support](https://kawaa.com/support/verification-results/): Learn how to interpret the verification results returned by the Kawaa API. ## Glossary Email and deliverability terms, one page each. - [Email glossary - Email marketing terms & definitions](https://kawaa.com/glossary/): Comprehensive glossary of email marketing and deliverability terms. Learn about SPF, DKIM, DMARC, bounce rates, spam traps, and more. - [A record - Email glossary](https://kawaa.com/glossary/a-record/): A DNS record that maps a domain name to an IPv4 address. Mail for a domain with no MX record goes to its A or AAAA address instead. - [Abuse complaint - Email glossary](https://kawaa.com/glossary/abuse-complaint/): When a recipient marks an email as spam or junk, generating a complaint to the sender's email provider. - [Backscatter - Email glossary](https://kawaa.com/glossary/backscatter/): Bounce messages sent to forged sender addresses, often caused by spam or viruses using fake return addresses. - [Blacklist - Email glossary](https://kawaa.com/glossary/blacklist/): A database of IP addresses or domains identified as sources of spam. Also called blocklist or DNSBL. - [Bounce rate - Email glossary](https://kawaa.com/glossary/bounce-rate/): The percentage of sent emails that could not be delivered. Calculated as (bounced emails / sent emails) × 100. - [Bounce - Email glossary](https://kawaa.com/glossary/bounce/): An email that cannot be delivered and is returned to the sender with an error message. - [CAN-SPAM Act - Email glossary](https://kawaa.com/glossary/can-spam-act/): US law establishing requirements for commercial email, including opt-out mechanisms and sender identification. - [Catch-all domain - Email glossary](https://kawaa.com/glossary/catch-all-domain/): A mail server configured to accept emails to any address at the domain, making individual mailbox verification impossible. Also called accept-all. - [Click-through rate (CTR) - Email glossary](https://kawaa.com/glossary/click-through-rate/): The percentage of email recipients who clicked on one or more links in an email. - [Cold email - Email glossary](https://kawaa.com/glossary/cold-email/): An unsolicited email sent to a recipient without prior contact or relationship. - [Complaint rate - Email glossary](https://kawaa.com/glossary/complaint-rate/): The percentage of recipients who mark your email as spam. Should be kept below 0.1%. - [Dedicated IP - Email glossary](https://kawaa.com/glossary/dedicated-ip/): An IP address used exclusively by one sender, giving full control over sender reputation. - [Deliverability - Email glossary](https://kawaa.com/glossary/deliverability/): The ability of an email to reach the recipient's inbox rather than being blocked or filtered to spam. - [Disposable email - Email glossary](https://kawaa.com/glossary/disposable-email/): A temporary email address created for short-term use, often to avoid spam or hide identity. - [DKIM - Email glossary](https://kawaa.com/glossary/dkim/): DomainKeys Identified Mail. An email authentication method using cryptographic signatures to verify sender identity. - [DMARC - Email glossary](https://kawaa.com/glossary/dmarc/): Domain-based Message Authentication, Reporting & Conformance. A policy framework building on SPF and DKIM. - [DNS - Email glossary](https://kawaa.com/glossary/dns/): Domain Name System. The internet's phone book that translates domain names to IP addresses. - [DNSBL - Email glossary](https://kawaa.com/glossary/dnsbl/): DNS-based Blackhole List. A blacklist queryable via DNS to check if an IP is flagged for spam. - [Domain reputation - Email glossary](https://kawaa.com/glossary/domain-reputation/): A score assigned to a sending domain based on email engagement, complaints, and sending practices. - [Double opt-in - Email glossary](https://kawaa.com/glossary/double-opt-in/): A subscription process requiring users to confirm their email address by clicking a verification link. - [Email authentication - Email glossary](https://kawaa.com/glossary/email-authentication/): Technical methods (SPF, DKIM, DMARC) to verify that an email comes from its claimed sender. - [Email client - Email glossary](https://kawaa.com/glossary/email-client/): Software used to read, send, and manage emails (e.g., Gmail, Outlook, Apple Mail). - [Email header - Email glossary](https://kawaa.com/glossary/email-header/): Metadata at the top of an email containing routing information, sender details, and authentication results. - [Email hygiene - Email glossary](https://kawaa.com/glossary/email-hygiene/): The practice of maintaining a clean email list by removing invalid, inactive, and risky addresses. - [Email service provider (ESP) - Email glossary](https://kawaa.com/glossary/email-service-provider/): A company that provides email marketing and sending services (e.g., Mailchimp, SendGrid, Klaviyo). - [Email verification - Email glossary](https://kawaa.com/glossary/email-verification/): The process of validating that an email address exists, is properly formatted, and can receive messages. - [Email warmup - Email glossary](https://kawaa.com/glossary/email-warmup/): Gradually increasing email sending volume on a new IP or domain to build sender reputation. - [Engagement rate - Email glossary](https://kawaa.com/glossary/engagement-rate/): A metric measuring how recipients interact with emails through opens, clicks, and replies. - [Envelope sender - Email glossary](https://kawaa.com/glossary/envelope-sender/): The email address used in the SMTP conversation, which may differ from the visible "From" address. - [Feedback loop (FBL) - Email glossary](https://kawaa.com/glossary/feedback-loop/): A service where ISPs notify senders when recipients mark their emails as spam. - [Free email provider - Email glossary](https://kawaa.com/glossary/free-email-provider/): Email services offering free accounts (e.g., Gmail, Yahoo, Outlook.com). Often indicate personal rather than business use. - [GDPR - Email glossary](https://kawaa.com/glossary/gdpr/): General Data Protection Regulation. EU law governing data privacy and consent for email marketing. - [Graymail - Email glossary](https://kawaa.com/glossary/graymail/): Legitimate email that recipients signed up for but no longer engage with, often filtered or ignored. - [Greylisting - Email glossary](https://kawaa.com/glossary/greylisting/): An anti-spam technique that temporarily rejects emails from unknown senders, expecting legitimate servers to retry. - [Hard bounce - Email glossary](https://kawaa.com/glossary/hard-bounce/): A permanent delivery failure, typically because the email address doesn't exist or the domain is invalid. - [Honeypot - Email glossary](https://kawaa.com/glossary/honeypot/): A type of spam trap - an email address created specifically to catch spammers harvesting addresses. - [IMAP - Email glossary](https://kawaa.com/glossary/imap/): Internet Message Access Protocol. A protocol for retrieving emails from a server while keeping them stored remotely. - [Inbox placement - Email glossary](https://kawaa.com/glossary/inbox-placement/): Whether an email lands in the primary inbox, promotions tab, or spam folder. Kawaa inbox placement testing is coming soon. - [IP reputation - Email glossary](https://kawaa.com/glossary/ip-reputation/): A score assigned to an IP address based on its email sending history and recipient engagement. - [IP warmup - Email glossary](https://kawaa.com/glossary/ip-warmup/): The process of gradually increasing sending volume from a new IP address to establish reputation. - [ISP - Email glossary](https://kawaa.com/glossary/isp/): Internet Service Provider. In email context, often refers to mailbox providers like Gmail, Yahoo, and Microsoft. - [List hygiene - Email glossary](https://kawaa.com/glossary/list-hygiene/): See email hygiene. Regular cleaning of email lists to remove invalid and risky addresses. - [Mail transfer agent (MTA) - Email glossary](https://kawaa.com/glossary/mail-transfer-agent/): Software that transfers email between mail servers over SMTP, such as Postfix, Sendmail or Microsoft Exchange. - [Mailbox provider - Email glossary](https://kawaa.com/glossary/mailbox-provider/): A service that hosts email accounts and manages inbox delivery (e.g., Gmail, Outlook, Yahoo). - [MIME - Email glossary](https://kawaa.com/glossary/mime/): Multipurpose Internet Mail Extensions. A standard for formatting non-text email content like attachments and HTML. - [MX record - Email glossary](https://kawaa.com/glossary/mx-record/): Mail Exchange record. A DNS record specifying the mail server responsible for receiving email for a domain. - [Open rate - Email glossary](https://kawaa.com/glossary/open-rate/): The percentage of delivered emails that recipients opened, as counted by a tracking pixel. Image blocking and privacy features skew it. - [Opt-in - Email glossary](https://kawaa.com/glossary/opt-in/): When a user gives explicit permission to receive emails, typically by subscribing to a list. - [Opt-out - Email glossary](https://kawaa.com/glossary/opt-out/): When a user withdraws permission to receive emails, typically by clicking an unsubscribe link. - [Phishing - Email glossary](https://kawaa.com/glossary/phishing/): Fraudulent emails designed to trick recipients into revealing sensitive information or clicking malicious links. - [POP3 - Email glossary](https://kawaa.com/glossary/pop3/): Post Office Protocol version 3. A protocol for downloading emails from a server to a local device. - [Pristine spam trap - Email glossary](https://kawaa.com/glossary/pristine-spam-trap/): An email address that was never used for legitimate purposes, created solely to catch spammers. - [Recycled spam trap - Email glossary](https://kawaa.com/glossary/recycled-spam-trap/): A previously valid email address repurposed as a spam trap after being abandoned for an extended period. - [Return path - Email glossary](https://kawaa.com/glossary/return-path/): The email address where bounce notifications are sent. Used in SPF authentication. - [Role-based email - Email glossary](https://kawaa.com/glossary/role-based-email/): An email address associated with a function rather than a person (e.g., info@, support@, sales@). - [Sender reputation - Email glossary](https://kawaa.com/glossary/sender-reputation/): A score reflecting the trustworthiness of an email sender based on sending practices and engagement. - [Sender Score - Email glossary](https://kawaa.com/glossary/sender-score/): A reputation rating from 0-100 assigned to sending IP addresses, provided by Validity (formerly Return Path). - [Shared IP - Email glossary](https://kawaa.com/glossary/shared-ip/): An IP address used by multiple senders, where reputation is influenced by all users' behavior. - [Single opt-in - Email glossary](https://kawaa.com/glossary/single-opt-in/): A subscription process where users are added to a list immediately after submitting their email, without confirmation. - [SMTP - Email glossary](https://kawaa.com/glossary/smtp/): Simple Mail Transfer Protocol. The standard protocol for sending emails between servers. - [Soft bounce - Email glossary](https://kawaa.com/glossary/soft-bounce/): A temporary delivery failure, often due to a full mailbox, server issues, or message size limits. - [Spam filter - Email glossary](https://kawaa.com/glossary/spam-filter/): Software that analyzes emails to identify and block spam from reaching the inbox. - [Spam trap - Email glossary](https://kawaa.com/glossary/spam-trap/): An email address used to identify spammers. Includes pristine traps, recycled traps, and typo traps. - [Spam - Email glossary](https://kawaa.com/glossary/spam/): Unsolicited bulk email, typically commercial in nature, sent without recipient consent. - [SPF - Email glossary](https://kawaa.com/glossary/spf/): Sender Policy Framework. A DNS-based email authentication method listing authorized sending servers for a domain. - [Spoofing - Email glossary](https://kawaa.com/glossary/spoofing/): Forging email headers to make a message appear to come from a different sender than the actual source. - [Sunsetting - Email glossary](https://kawaa.com/glossary/sunsetting/): The practice of removing unengaged subscribers from email lists to maintain list quality and sender reputation. - [Syntax validation - Email glossary](https://kawaa.com/glossary/syntax-validation/): Checking if an email address follows the correct format (e.g., user@domain.com) according to RFC standards. - [Throttling - Email glossary](https://kawaa.com/glossary/throttling/): Rate limiting email sending speed to avoid overwhelming receiving servers or triggering spam filters. - [TLS - Email glossary](https://kawaa.com/glossary/tls/): Transport Layer Security. Encryption protocol securing email transmission between servers. - [Transactional email - Email glossary](https://kawaa.com/glossary/transactional-email/): Automated emails triggered by user actions (e.g., order confirmations, password resets, notifications). - [Typo trap - Email glossary](https://kawaa.com/glossary/typo-trap/): A spam trap based on common misspellings of popular domains (e.g., gmial.com instead of gmail.com). - [Unsubscribe - Email glossary](https://kawaa.com/glossary/unsubscribe/): The process of removing oneself from an email list. Required by law to be easy and honored promptly. - [Whitelist - Email glossary](https://kawaa.com/glossary/whitelist/): A list of approved senders whose emails bypass spam filters. Also called allowlist or safelist. ## Legal Terms, privacy, data processing and accessibility. - [Accessibility statement](https://kawaa.com/accessibility/): Learn about Kawaa's commitment to digital accessibility and how we strive to make our services usable by everyone. - [Cookie policy](https://kawaa.com/cookies/): How Kawaa uses cookies and similar technologies, which third-party cookies are set, and how to manage or turn them off. - [Data processing agreement](https://kawaa.com/dpa/): Data Processing Agreement (DPA) for GDPR compliance when using Kawaa services. - [Privacy policy](https://kawaa.com/privacy/): Learn how Kawaa collects, uses, and protects your personal information. - [Terms of service](https://kawaa.com/terms/): The terms and conditions for using Kawaa: accounts, acceptable use, API usage, payment, data processing, liability and termination. ## Other pages - [Careers - Work on Email Infrastructure at Kawaa](https://kawaa.com/careers/): Open roles at Kawaa. Help build the email verification infrastructure that senders rely on before every campaign.