Settings guide
Gmail SMTP Server Settings
The Gmail SMTP server is smtp.gmail.com on port 587 (STARTTLS) or 465 (SSL/TLS). Below are the full settings for Gmail, Google Workspace, Outlook and Microsoft 365, plus the daily sending limits for each.
- SMTP server
- smtp.gmail.com
- Port (STARTTLS)
- 587
- Port (SSL/TLS)
- 465
- Username
- [email protected]
- Password
- App Password or OAuth
- Authentication
- Required
IMAP (incoming): imap.gmail.com, port 993, SSL
Gmail & Google Workspace
Gmail SMTP settings
| Setting | Value |
|---|---|
| SMTP server | smtp.gmail.com |
| Port with STARTTLS | 587 |
| Port with SSL/TLS | 465 |
| Authentication | Required |
| Username | Your full Gmail or Google Workspace address |
| Password | An App Password (needs 2-Step Verification), or OAuth 2.0 |
| IMAP server (incoming) | imap.gmail.com |
| IMAP port | 993 |
Your regular Google password won't work
Gmail SMTP relay for Google Workspace
Sending from a website, printer or app rather than a person's mailbox? Workspace admins can enable the SMTP relay service in the Admin console under Apps → Google Workspace → Gmail → Routing.
| Setting | Value |
|---|---|
| Relay server | smtp-relay.gmail.com |
| Ports | 25, 465 or 587 |
| Authentication | Allowed IP addresses, SMTP AUTH, or both |
| Daily limit | 10,000 recipients per user |
Other providers
Outlook, Microsoft 365, Yahoo and iCloud SMTP settings
Every provider below requires authentication and an encrypted connection.
| Provider | SMTP server | Port | Encryption |
|---|---|---|---|
| Microsoft 365 / Office 365 | smtp.office365.com | 587 | STARTTLS |
| Outlook.com / Hotmail | smtp-mail.outlook.com | 587 | STARTTLS |
| Yahoo Mail | smtp.mail.yahoo.com | 465 or 587 | SSL/TLS or STARTTLS |
| iCloud Mail | smtp.mail.me.com | 587 | STARTTLS |
Microsoft 365: use OAuth, not basic authentication
Ports
SMTP ports: 25, 465, 587 and 2525 compared
The SMTP port number tells the server what kind of connection to expect. Apps and outreach tools that sign in to a mailbox should use 587 or 465. Port 25 is for server-to-server delivery.
| Port | Encryption | What it's for | When to use it |
|---|---|---|---|
| 587 | STARTTLS (starts plain, upgrades to TLS) | Message submission: apps and mail clients sending through a mailbox | Your default. Gmail, Microsoft 365, Yahoo and iCloud all accept it. |
| 465 | Implicit TLS (encrypted from the first byte) | Message submission over TLS | When the app asks for SSL/TLS. Works with Gmail and Yahoo, not Microsoft 365. |
| 25 | None by default; STARTTLS optional | Relay between mail servers | Server-to-server only, or the Workspace relay. Often blocked by ISPs and cloud hosts. |
| 2525 | Same as 587 | Not an official SMTP port; a fallback some sending services offer | Only if your provider documents it and 587 is blocked. Gmail and Microsoft 365 don't list it. |
Which SMTP port should you use?
- Use 587 with STARTTLS unless your provider says otherwise.
- If the app only offers SSL/TLS, use 465 with Gmail or Yahoo. Microsoft 365 needs 587.
- If the connection times out, your network is probably blocking the port: switch between 587 and 465.
- Don't point an app or mail client at port 25. It's meant for servers, and it's the port most often blocked.
SMTP port 25
Port 25 is the original SMTP port and still carries mail between servers: when Google delivers your message to a prospect, it connects to their mail server on 25. Because it has been heavily abused for spam, many ISPs and cloud hosts block outbound connections on it. Google Cloud, for example, blocks port 25 to destinations outside your network. You'd only use it yourself for the Gmail SMTP relay (smtp-relay.gmail.com accepts 25, 465 or 587) or Google's restricted server aspmx.l.google.com, which only takes port 25 and only delivers to Gmail and Google Workspace users.
Connecting mailboxes to an outreach tool? Skip the port settings.
SMTP only sends. Reading mail uses IMAP on port 993: see IMAP vs SMTP. Microsoft 365 details, including why port 465 fails there, are in Office 365 SMTP settings.
Sources (checked October 2026): Google Workspace Admin Help · Google Cloud: sending email · RFC 6409 · RFC 8314 · Twilio SendGrid SMTP ports
Limits
Daily sending limits, and the number that actually matters
Provider limits are hard ceilings. For cold email the safe volume per mailbox is far lower, because reputation, not the quota, is what runs out first.
Maximum emails per mailbox per day
Provider limits from Google and Microsoft documentation. Cold email figure is the planning number we use per mailbox.
| Free Gmail | ~500 |
|---|---|
| Google Workspace | 2,000 |
| Workspace SMTP relay | 10,000 |
| Microsoft 365 | 10,000 |
| Safe cold email | 30 |
That gap is why outbound teams send from many mailboxes across several domains instead of one heavily used account. Need 1,500 emails a day? That's about 50 mailboxes, not one. See how many mailboxes you need or get them set up with Google Workspace business email.
Troubleshooting
Gmail SMTP errors and fixes
| Error | Cause | Fix |
|---|---|---|
535-5.7.8 Username and Password not accepted | Wrong password, or a normal password where an App Password is needed. | Create an App Password or switch the app to OAuth. |
534-5.7.9 Application-specific password required | 2-Step Verification is on. | Generate an App Password for this app. |
| Connection timed out | Your host or firewall blocks the port. | Try 587 instead of 465 (or the reverse). Many cloud hosts block port 25. |
550-5.4.5 Daily user sending limit exceeded | The mailbox hit its daily quota. | Wait up to 24 hours. Spread volume across more mailboxes. |
421-4.7.0 Try again later | Google is temporarily throttling you. | Send more slowly and retry later. |
Mail sends but lands in spam? That's an authentication or reputation problem, not an SMTP one. Run your domain through the SPF, DKIM and DMARC checker.
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Or see pricing →Frequently asked questions
What is the SMTP server for Gmail?
smtp.gmail.com. Use port 587 with STARTTLS or port 465 with SSL/TLS, and sign in with your full Gmail or Google Workspace address.
What port does Gmail SMTP use?
Port 587 (STARTTLS) or port 465 (SSL/TLS). Both are encrypted. Port 25 is for server-to-server relay and is blocked by many hosts and ISPs.
What are the SMTP port numbers?
587 is the standard port for apps and mail clients sending through a mailbox, using STARTTLS. 465 does the same over TLS from the first byte. 25 is for relay between mail servers. 2525 isn't an official SMTP port, but some sending services such as SendGrid offer it as a fallback.
What is SMTP port 25 used for?
Delivering mail between servers: your provider connects to the recipient's mail server on port 25. Many ISPs and cloud hosts block outbound port 25 (Google Cloud blocks it to external destinations), so apps should submit mail on 587 or 465 instead.
What password do I use for Gmail SMTP?
Not your normal Google password. Use Sign in with Google (OAuth) if your app supports it. Otherwise turn on 2-Step Verification and create an App Password in your Google Account's security settings.
What is the Outlook SMTP server?
smtp-mail.outlook.com for Outlook.com and Hotmail accounts, and smtp.office365.com for Microsoft 365 work accounts. Both use port 587 with STARTTLS.
How many emails can I send per day through Gmail SMTP?
Google Workspace allows 2,000 messages per user per day (500 on trial accounts). Free Gmail accounts are limited to roughly 500 recipients per day. Go over and Google blocks sending for up to 24 hours.
Can I use Gmail SMTP for cold email?
Technically yes, but personal Gmail accounts aren't meant for outreach. Use Google Workspace mailboxes on separate domains, keep each to about 30 cold emails a day, and connect them with OAuth instead of raw SMTP.