Gmail SMTP Server Settings: The Definitive Reference

Gmail SMTP Server Settings (Quick Reference)

The standard Gmail SMTP setup:

Setting	Value
SMTP server / host	smtp.gmail.com
SMTP port	587 (STARTTLS) or 465 (SSL/TLS)
Encryption	TLS required
Authentication	Yes (full Gmail address + app password or OAuth2)
Daily limit (free)	500 messages
Daily limit (Workspace)	2,000 messages

These settings work for personal Gmail accounts and Google Workspace. Gmail SMTP host, SMTP host for Gmail, and Gmail server settings SMTP all refer to the same smtp.gmail.com server.

Three Ways to Send Through Gmail

1. SMTP AUTH (smtp.gmail.com)

Standard SMTP submission. Authenticate as a Gmail user, send mail. Suitable for:

• Apps that send "from" a specific user
• Personal scripts and tools
• Low-volume notifications

2. SMTP Relay (smtp-relay.gmail.com) — Workspace only

Higher-volume relay for Google Workspace customers. Suitable for:

• Apps sending many messages to multiple recipients
• Scenarios requiring IP-based authentication
• Up to 10,000 messages/day

3. Gmail API

For Google Workspace developers, the Gmail API supports OAuth2-based sending without SMTP. More setup but better integration with modern apps.

SMTP AUTH Setup (Standard Method)

For most use cases. App configuration:

• SMTP server: smtp.gmail.com
• SMTP port: 587 (recommended, uses STARTTLS)
• Encryption: STARTTLS
• Username: full Gmail address (e.g., [email protected])
• Password: app password if 2-Step Verification is on, otherwise account password

App Password Generation

Required when 2-Step Verification is enabled (which is now the default for Workspace):

1. Go to myaccount.google.com/security
2. Under "Signing in to Google," click 2-Step Verification
3. Scroll to bottom → App passwords
4. Generate password for the app/device
5. Use the generated 16-character password in your SMTP config

SMTP Relay Setup (Google Workspace)

For higher-volume sending. Admin must configure:

1. Google Workspace Admin Console → Apps → Google Workspace → Gmail → Routing
2. SMTP Relay Service → Configure
3. Allowed senders (any address, mailbox addresses only, or addresses in your domain)
4. Authentication (require SMTP authentication, accept mail from specified IP, or both)
5. Require TLS encryption
6. Save

Then in your app:

• SMTP server: smtp-relay.gmail.com
• SMTP port: 587 or 465
• Authentication: per your config (IP-based or SMTP AUTH or both)

Common Gmail SMTP Settings Issues

"Username and Password not accepted"

Most common cause: using account password instead of app password when 2-Step Verification is on. Generate an app password and use that.

Second most common: less-secure app access blocked. Google deprecated this option for most accounts — must use app password or OAuth2.

"5.7.0 Authentication Required"

You're using port 25, which Gmail doesn't accept for client submissions. Switch to 587 with STARTTLS or 465 with SSL/TLS.

"Daily user sending quota exceeded"

You hit the 500 (free) or 2,000 (Workspace) daily limit. Wait 24 hours for the rolling window to reset, or upgrade your sending architecture (use smtp-relay or move to a dedicated ESP).

"Mail sent through Gmail goes to recipient's spam"

Gmail's SMTP server has decent reputation but isn't optimized for application sends. The fix is usually: ensure SPF includes _spf.google.com, configure DKIM in Workspace Admin, and consider moving to a dedicated transactional ESP for app-sent mail.

Gmail SMTP Out Restrictions

What you cannot do via Gmail SMTP:

• Send more than 500/day (free) or 2,000/day (Workspace) per user
• Send via port 25 (not supported)
• Send mass marketing or cold email at any meaningful volume
• Send without authentication

When to Move Off Gmail SMTP

If you find yourself fighting Gmail SMTP limits or deliverability, you've outgrown it. Move to:

• Transactional: Postmark, Resend, SendGrid, Mailgun
• Marketing: Klaviyo, Mailchimp, Brevo
• Cold email: Instantly, Smartlead (using Workspace as the underlying inbox)

Gmail SMTP is fine for low-volume notifications and human-sent mail. It's not a sending platform.

Practitioner note: I see "Gmail SMTP server outgoing not working" tickets constantly, and 80% trace to two issues: 1) the user didn't generate an app password when 2-Step Verification was on, or 2) the app is hardcoded to port 25 which Gmail rejects. The fix is always one of these.

Practitioner note: Gmail's smtp-relay.gmail.com is underutilized — many Workspace customers don't know it exists. For internal app sending where you want higher limits and IP-based auth instead of per-mailbox app passwords, it's a much better fit than smtp.gmail.com.

Practitioner note: Gmail SMTP service is not a substitute for transactional infrastructure. I've seen SaaS teams send password resets via Gmail SMTP, hit the daily limit, and have customers unable to log in. For anything where deliverability matters, use a real transactional ESP.

If you're hitting Gmail SMTP limits or deliverability problems and need help architecting a proper sending infrastructure, book a consultation. I migrate teams from Gmail SMTP to scalable transactional and marketing infrastructure regularly.

Sources

• Google: Send email from a printer, scanner, or app
• Google: Gmail IMAP, POP, and SMTP settings
• Google: Google Workspace SMTP relay service
• Mailtrap: Gmail SMTP guide

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v1.0 · May 2026