{"id":43294,"date":"2026-02-04T11:06:08","date_gmt":"2026-02-04T08:06:08","guid":{"rendered":"https:\/\/snov.io\/knowledgebase\/?p=43294"},"modified":"2026-03-05T18:32:06","modified_gmt":"2026-03-05T15:32:06","slug":"api-vs-smtp-when-to-choose-which-connection","status":"publish","type":"post","link":"https:\/\/snov.io\/knowledgebase\/api-vs-smtp-when-to-choose-which-connection\/","title":{"rendered":"How to choose between API and SMTP email connections"},"content":{"rendered":"<p><span style=\"font-weight: 400;\">In this article, we\u2019ll explain when to use API and SMTP connection types for Gmail and Outlook email accounts in <\/span><span style=\"font-weight: 400;\">Snov.io<\/span><span style=\"font-weight: 400;\">.<\/span><\/p>\n<p><b>Why connection type matters<\/b><\/p>\n<p><span style=\"font-weight: 400;\">Your email connection type plays a big role when using Snov.io. <\/span><span style=\"font-weight: 400;\">Choosing the right connection for sending can improve deliverability and replies.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Select connection depending on the current usage:<\/span><\/p>\n<ul>\n<li aria-checked=\"false\" aria-level=\"1\"><b>Gmail\/Outlook API \u2192<\/b><span style=\"font-weight: 400;\"> for sending campaigns<\/span><\/li>\n<\/ul>\n<ul>\n<li aria-checked=\"false\" aria-level=\"1\"><b>Gmail\/Outlook SMTP \u2192 <\/b><span style=\"font-weight: 400;\">for warm-up and <\/span>advanced settings (using alias sender account, tracking replies on another address)<\/li>\n<\/ul>\n<div class=\"notification-block learn\">\n<div class=\"notification-block__icon\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/themes\/knowledgebase-n\/assets\/img\/fluent_chat-warning-16-regular.svg\" alt=\"learn\" width=\"32\" height=\"32\" \/><\/div>\n<div class=\"notification-block__text\"><strong data-start=\"129\" data-end=\"138\">Note:<\/strong> API connection uses direct Gmail or Microsoft sign-in to connect your mailbox. SMTP connection is set up using your email credentials and a third-party app password.<\/div>\n<\/div>\n<p><span style=\"font-weight: 400;\">Both Gmail and Outlook mailboxes can be connected using either API or SMTP in <\/span><span style=\"font-weight: 400;\">Snov.io<\/span><span style=\"font-weight: 400;\">. <\/span><span style=\"font-weight: 400;\">The choice depends on the current usage stage of the mailbox.<\/span><\/p>\n<h2><b>When to choose API connection<\/b><\/h2>\n<p>Snov.io recommends using API connections for campaigns. For best deliverability, keep campaign volume low <a href=\"https:\/\/snov.io\/knowledgebase\/email-sending-limits\/\" target=\"_blank\" rel=\"noopener\">(up to 30 emails\/day per account)<\/a>.<\/p>\n<p>For API-connected accounts, the default recommended sending limits are:<\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>15 emails\/day for Gmail<\/b><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>5 emails\/day for Outlook<\/b><\/li>\n<\/ul>\n<h3><strong>API connection for campaigns<\/strong><\/h3>\n<p><b>Emails sent via API:<\/b><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Use the provider\u2019s native sending infrastructure<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Are treated as personal or manual emails<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Are less likely to land in spam<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Align better with Gmail and Outlook sending rules<\/span><\/li>\n<\/ul>\n<p><b>Emails sent via SMTP<\/b><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Use shared sender IP addresses<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Spam filters apply stricter rules (impacts deliverability)<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Lower average deliverability for cold outreach<\/span><\/li>\n<\/ul>\n<p data-start=\"55\" data-end=\"202\">To connect your mailbox via API, select it for the <strong data-start=\"135\" data-end=\"144\">Gmail<\/strong> or <strong data-start=\"148\" data-end=\"161\">Microsoft<\/strong> during <a href=\"https:\/\/app.snov.io\/account\/email-account\" target=\"_blank\" rel=\"noopener\">the email connection<\/a>.<\/p>\n<p data-start=\"55\" data-end=\"202\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-44789 wp-block-image shadow\" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_21_AM.png\" alt=\"\" width=\"1424\" height=\"677\" srcset=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_21_AM.png 1424w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_21_AM-300x143.png 300w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_21_AM-1024x487.png 1024w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_21_AM-768x365.png 768w\" sizes=\"(max-width: 1424px) 100vw, 1424px\" \/><\/p>\n<h2><b>When to choose SMTP connection<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">SMTP connections are required to <a href=\"https:\/\/app.snov.io\/deliverability\/#\/warm-up\" target=\"_blank\" rel=\"noopener\">warm-up Gmail mailboxes<\/a> <\/span><span style=\"font-weight: 400;\">or when you need <\/span>advanced sending settings<span style=\"font-weight: 400;\">.<\/span><\/p>\n<h3><strong>SMTP connection for warm-up<\/strong><\/h3>\n<p>For warm-up, you\u2019ll need a higher daily limit (the recommended warm-up goal is 40 emails\/day).<\/p>\n<p>Since warm-up emails count as real sends, running warm-up above the recommended API limits (15 emails\/day) can affect sender reputation.<\/p>\n<p><span style=\"font-weight: 400;\">To warm up account, use a <\/span>separate SMTP connection <span style=\"font-weight: 400;\">and<\/span> <span style=\"font-weight: 400;\">set <\/span><a href=\"https:\/\/app.snov.io\/account\/email-account\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">the daily sending limit<\/span><\/a><span style=\"font-weight: 400;\"> to <\/span><b>40 emails\/day<\/b><span style=\"font-weight: 400;\">.<\/span><\/p>\n<h2><strong>Recommended setup for email connection<\/strong><\/h2>\n<p><span style=\"font-weight: 400;\">Create two separate connections for the same email account \u2014 one via API and one via SMTP.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">To warm-up your account, use the SMTP connection. After your warm-up is finished, choose the API-connected account for sending campaigns.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">You can safely add the same email account twice in Snov.io using different connection types, using both <\/span><b>API and SMTP<\/b><span style=\"font-weight: 400;\">.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Just make sure to select the correct type depending on the current usage:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Gmail\/Outlook API \u2192 <\/b><span style=\"font-weight: 400;\">for<\/span> <span style=\"font-weight: 400;\">email campaigns<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Gmail\/Outlook SMTP \u2192 <\/b><span style=\"font-weight: 400;\">for<\/span> <span style=\"font-weight: 400;\">warm-up<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Connect the account via SMTP \u2192 Run warm-up until completed \u2192 Switch back to API for sending campaigns.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">This is what the Gmail API connection type looks like in your <a href=\"https:\/\/app.snov.io\/account\/email-account\" target=\"_blank\" rel=\"noopener\">email account settings.<\/a><\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-44790 wp-block-image shadow\" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_36_AM.png\" alt=\"\" width=\"1424\" height=\"677\" srcset=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_36_AM.png 1424w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_36_AM-300x143.png 300w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_36_AM-1024x487.png 1024w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_36_AM-768x365.png 768w\" sizes=\"(max-width: 1424px) 100vw, 1424px\" \/><\/p>\n<p><span style=\"font-weight: 400;\">This is what the SMTP connection type looks like in your <a href=\"https:\/\/app.snov.io\/account\/email-account\" target=\"_blank\" rel=\"noopener\">email account settings<\/a>:<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-44780 wp-block-image shadow\" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/smtp-connection.png\" alt=\"\" width=\"1424\" height=\"677\" srcset=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/smtp-connection.png 1424w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/smtp-connection-300x143.png 300w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/smtp-connection-1024x487.png 1024w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/smtp-connection-768x365.png 768w\" sizes=\"(max-width: 1424px) 100vw, 1424px\" \/><\/p>\n<h2><strong>Warming-up Gmail accounts<\/strong><\/h2>\n<p><span style=\"font-weight: 400;\">Gmail API connections are not supported in <\/span><a href=\"https:\/\/app.snov.io\/deliverability\/#\/warm-up\/new\/settings\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">Email Warm-up<\/span><\/a><span style=\"font-weight: 400;\">. Change your account\u2019s connection type to SMTP to add it to warm-up.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">SMTP-connected accounts have full compatibility with warm-up features, including:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Warm-up per provider (Gmail \/ Outlook)<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Custom tracking domain warm-up<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Premium warm-up pool (with business domains)<\/span><\/li>\n<\/ul>\n<h3><strong>Connect Gmail account via SMTP<\/strong><\/h3>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The password must be a third-party app password, not your main email password<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Two-factor authentication must be enabled in the Security settings<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">App password is different from your email login password<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">To enable third-party app passwords with Gmail, you need to enable two-factor authentication as well. Learn how to create <\/span><a href=\"https:\/\/support.google.com\/mail\/answer\/185833?hl=en\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">third-party app passwords on Google accounts<\/span><\/a><span style=\"font-weight: 400;\">.<\/span><\/p>\n<h2><strong>Warming-up Microsoft Outlook accounts<\/strong><\/h2>\n<p><span style=\"font-weight: 400;\">If your email is hosted on Office 365:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Make sure <\/span><a href=\"https:\/\/learn.microsoft.com\/en-us\/exchange\/clients-and-mobile-in-exchange-online\/authenticated-client-smtp-submission\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">SMTP AUTH<\/span><\/a><span style=\"font-weight: 400;\"> is enabled in your Microsoft email settings<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">If you\u2019re not sure how to check or enable this, reach out to your Office 365 admin<\/span><\/li>\n<\/ul>\n<h3><strong>Connect Microsoft Outlook via SMTP<\/strong><\/h3>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Use a <\/span><b>third-party app password<\/b><span style=\"font-weight: 400;\">, not your main email password<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">App passwords must be enabled in your Microsoft account<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Learn how to configure <\/span><a href=\"https:\/\/learn.microsoft.com\/en-us\/entra\/identity\/authentication\/howto-mfa-app-passwords\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">third-party app passwords for Microsoft accounts<\/span><\/a><span style=\"font-weight: 400;\">.<\/span><\/p>\n<h2><strong>SMTP for advanced settings<\/strong><\/h2>\n<p><span style=\"font-weight: 400;\">You may also benefit from SMTP connection when you need advanced email sending settings.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">These email settings are only available for SMTP connections.<\/span><\/p>\n<p><b>Advanced SMTP settings include<\/b><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Use alias sender name: <\/b><span style=\"font-weight: 400;\">Send from a different <\/span><b>From email address<\/b><span style=\"font-weight: 400;\"> than the actual mailbox<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Use a different reply-to address: <\/b><span style=\"font-weight: 400;\">Automatically forward replies to another mailbox<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Track replies on another address: <\/b><span style=\"font-weight: 400;\">Set a different IMAP account for tracking replies<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">For both <\/span><b>API- and SMTP-connected accounts<\/b><span style=\"font-weight: 400;\">, you can:<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Check domain health<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Run deliverability tests<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Add custom tracking domains<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Sync inboxes with Unibox<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Find them in <\/span><b>Optional settings<\/b><span style=\"font-weight: 400;\"> for each account.<\/span><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-44794 wp-block-image shadow\" src=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_39_AM.png\" alt=\"\" width=\"1424\" height=\"677\" srcset=\"https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_39_AM.png 1424w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_39_AM-300x143.png 300w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_39_AM-1024x487.png 1024w, https:\/\/snov.io\/knowledgebase\/wp-content\/uploads\/2026\/02\/My-account-02-05-2026_10_39_AM-768x365.png 768w\" sizes=\"(max-width: 1424px) 100vw, 1424px\" \/><\/p>\n<div class=\"notification-block note-gray\">\n<div class=\"notification-block__text\">\n<h3><strong>Related articles<\/strong><\/h3>\n<p><a href=\"https:\/\/snov.io\/knowledgebase\/how-to-connect-your-gmail-account-to-snovio-via-smtp\/\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">Learn how to connect Gmail SMTP accounts<\/span><\/a><\/p>\n<p><a href=\"https:\/\/snov.io\/knowledgebase\/how-to-start-warming-up-your-mailbox-with-snov-io\/\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">How to improve deliverability before cold outreach<\/span><\/a><\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>In this article, we\u2019ll explain when to use API and SMTP connection types for Gmail and Outlook email accounts in Snov.io. Why connection type matters Your email connection type plays a big role when using Snov.io. Choosing the right connection for sending can improve deliverability and replies. Select connection depending on the current usage: Gmail\/Outlook [&hellip;]<\/p>\n","protected":false},"author":16,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1936],"tags":[],"_links":{"self":[{"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/posts\/43294"}],"collection":[{"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/users\/16"}],"replies":[{"embeddable":true,"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/comments?post=43294"}],"version-history":[{"count":23,"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/posts\/43294\/revisions"}],"predecessor-version":[{"id":45186,"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/posts\/43294\/revisions\/45186"}],"wp:attachment":[{"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/media?parent=43294"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/categories?post=43294"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/snov.io\/knowledgebase\/wp-json\/wp\/v2\/tags?post=43294"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}