Fastmail SMTP Settings
Paid ad-free mail host where every client needs its own scoped app password.
Search for your email provider
Outgoing mail (SMTP)
SMTP server
smtp.fastmail.com
Port. STARTTLS
587
Port. SSL/TLS
465
Security
SSL/TLS on 465 (recommended) or STARTTLS on 587.
Incoming mail (IMAP)
IMAP server
imap.fastmail.com
Port. SSL/TLS
993
Port. STARTTLS
143
Incoming mail (POP3)
POP3 server
pop.fastmail.com
Port. SSL/TLS
995
Port. STARTTLS
110
Sending limits & login
Daily send limit
Generous per-plan limits aimed at personal and small-business use.
Authentication
Requires an app password: your login password will not work in mail clients.
App password
Create one at Settings > Privacy & Security > App passwords.
Fastmail requires an app password for every third-party SMTP, IMAP or POP connection.
Sending cold email? EmailChaser manages inboxes, warmup and deliverability for you.
Try EmailChaser freeFind the SMTP, IMAP and POP3 server settings for any email provider. Free, with no signup, every field copies with one click.
Fastmail SMTP, IMAP and POP3 settings
Fastmail is a paid mail service with no free plan, and it never accepts your normal login inside a mail app. Every client gets its own app password, scoped to Mail, Contacts and Calendars or narrower. The trap is the cheapest tier, Basic, now sold as Business Basic: Fastmail blocks IMAP, POP, SMTP, CalDAV and CardDAV on it, so no app password can even be created.
For incoming mail, use the IMAP server imap.fastmail.com on port 993, or POP3 at pop.fastmail.com on port 995. Pick the exact values from the tool above and copy them straight into your mail client.
Checked against Fastmail's own documentation: fastmail.help. Ports and limits change, so check there too if something will not connect.
Fastmail settings at a glance
One card with every server and port on it. Right click to save it, or share the page and this is the preview people see.
What to enter as your Fastmail username and password
Wrong credentials, not a wrong port, are the usual reason a Fastmail connection fails. These are the exact values to type.
Your full Fastmail address, for example you@fastmail.com or you@yourdomain.com
An app password created in Fastmail settings. Your normal password and your two-step verification password both fail here.
Get your app passwordHow to set up Fastmail in a mail client
The exact path through Fastmail's own settings, in order.
- 1
Confirm you are not on a Basic plan
Fastmail states that Basic plans do not include access to IMAP, SMTP, CalDAV or CardDAV. On Basic you cannot create an app password and no mail client will connect. Any other plan works: Individual, Duo or Family on the personal side, Business Standard or Business Professional on the business side.
- 2
Open Settings then Privacy & Security
In the Fastmail web interface go to Settings > Privacy & Security and find the Connected apps & API tokens section.
- 3
Create a new app password
Click Manage app passwords and access, then New app password. If a Verify it's you box appears, enter your password and click Continue.
- 4
Set the access scope to Mail
Name the password after the device, then leave access on the default Mail, Contacts & Calendars. A Files (WebDAV) scoped password will not send or receive mail.
- 5
Copy the generated password
Click Generate password. The next page shows the password, so paste it straight into the mail app.
- 6
Enter the server settings
SMTP smtp.fastmail.com port 465 with SSL/TLS (not STARTTLS), IMAP imap.fastmail.com port 993, POP pop.fastmail.com port 995. Port 587 with STARTTLS is the SMTP fallback.
What Fastmail looks like filled in
Every mail client asks for the same handful of fields. Here they are with Fastmail's values already in place.
Account settings: Fastmail
Server
smtp.fastmail.comPort
465Encryption
SSL/TLSAuthentication
RequiredUsername
Your full Fastmail address, for example you@fastmail.com or you@yourdomain.comPassword
An app password created in Fastmail settings. Your normal password and your two-step verification password both fail here.Server
imap.fastmail.comPort
993Encryption
SSL/TLSAn illustration of the fields, not a screenshot of any one app. Field names differ slightly between Outlook, Apple Mail and Thunderbird; the values do not.
Fastmail SMTP settings in Thunderbird
The outgoing server dialog with Fastmail's details entered. Outlook and Apple Mail ask for the same four things under slightly different names.
Which port should you use for Fastmail?
SSL/TLS on 465 (recommended) or STARTTLS on 587.
STARTTLS
Starts as a plain connection, then upgrades to an encrypted one. The modern standard for sending.
SSL/TLS
Encrypted from the first byte. Widely supported and a good choice when 587 is blocked.
Plain SMTP
Meant for server-to-server relay. Home networks and cloud hosts block it, so do not use it to send from a client.
Why your Fastmail connection is failing
The failures people actually hit with Fastmail, and what fixes each one.
You are on a Basic plan, which Fastmail excludes from third-party app access. IMAP, POP, SMTP, CalDAV and CardDAV need one of the higher plans.
You pasted your normal Fastmail password or your two-step verification password. Only an app password authenticates over IMAP, POP and SMTP.
The app password was created with a scope that excludes mail, such as Files (WebDAV). Create another with access set to Mail, Contacts & Calendars or Mail, then replace it in the app.
Fastmail runs proxy servers that answer on any port: imaps-proxy.fastmail.com, pops-proxy.fastmail.com and smtps-proxy.fastmail.com.
The device is missing the Let's Encrypt ISRG Root X1 root certificate. Install that root certificate or update the operating system.
Fastmail sending limits
There is also a 10 minute cap set at half the hourly figure, plus a smaller unpublished cap on the number of distinct recipient addresses.
Per day
4,000 messages on Basic, 8,000 on Individual, Duo, Family and Business Standard, 16,000 on Business Professional; 120 on trial accounts
Per hour
Half the daily figure, so 4,000 on an 8,000 plan and 8,000 on Business Professional
Max attachment
70 MB total message size, which is roughly 50 MB of attachments after encoding
Fastmail quirks by mail client
Outlook
Fastmail reports that Outlook can take hours to sync or show a Something went wrong error, and that rebuilding the account from scratch usually clears it.
Apple Mail
On a Mac, Fastmail's automatic setup tool downloads a configuration file that enters the app password and servers for you.
Sending cold email through Fastmail
Generous per-plan limits aimed at personal and small-business use. Requires an app password: your login password will not work in mail clients.
Those caps make single-mailbox sending fine for personal mail but a poor fit for cold outreach at volume. Emailchaser spreads sending across warmed inboxes and manages deliverability, so you can scale without burning Fastmail accounts.
Other consumer email providers
Setting up more than one mailbox? These sit in the same category as Fastmail.
Common questions about Fastmail SMTP settings
What are Fastmail's SMTP settings?
Fastmail's outgoing (SMTP) server is smtp.fastmail.com. Use port 587 (STARTTLS) or 465 (SSL/TLS). SSL/TLS on 465 (recommended) or STARTTLS on 587. Sign in with your full email address and password (or app password).
What is Fastmail's IMAP or POP3 server?
Fastmail's incoming IMAP server is imap.fastmail.com on port 993 (SSL/TLS). If you prefer POP3, use pop.fastmail.com on port 995.
Which port should I use for Fastmail?
Use port 587 with STARTTLS wherever it's offered, it's the modern standard for authenticated sending. Port 465 with SSL/TLS is a solid alternative. Avoid port 25, which most networks block for client sending. Fastmail's recommended value is above.
Why won't my Fastmail SMTP connection work?
Check authentication first: Requires an app password: your login password will not work in mail clients. Create one at Settings > Privacy & Security > App passwords. Then confirm the host, port and security method match exactly, a 587/SSL or 465/STARTTLS mismatch will fail to connect.
Can I send bulk or cold email through Fastmail?
Not at scale. Generous per-plan limits aimed at personal and small-business use. Providers throttle bursts to fight spam, so pushing cold email through one mailbox hits limits and wrecks deliverability. High-volume outreach belongs on dedicated infrastructure that spreads sending across warmed inboxes, which is what Emailchaser does.
Why can I not add Fastmail to the iPhone Mail app?
If you are on a Basic plan there is no IMAP access at all, so the native Mail app cannot connect whatever you type. On any other plan it works once you create an app password and use imap.fastmail.com on port 993.
Do I need a separate app password for every device?
Fastmail is built around one app password per app or device, each with its own name. That way you can revoke a lost phone without changing your main password or reconfiguring anything else. Each one can also be limited to only the data that app actually needs.
Should I send on port 465 or port 587?
Fastmail lists 465 as the default and notes the encryption is enabled but is not STARTTLS, so pick SSL/TLS in your client. Port 587 with STARTTLS is offered as the alternative if your network blocks 465.
Ready to 10x your pipeline?
Send your first cold email campaign today.
Start my free trialAddress: 151 Calle de San Francisco San Juan, Puerto Rico
Email: support@emailchaser.com
Product
Cold Email SoftwareAutopilotEmail FinderCampaignsSales CRMLead FinderEmail AccountsEmail WarmupEmail VerifierCold Email APIMCP ServerAPI documentationWho it's for
FreelancersFoundersSales teamsMarketing agenciesRecruitment agenciesLead generation agenciesComparisons
Best cold email softwareInstantly alternativesSmartlead alternativesInstantly vs EmailchaserSmartlead vs EmailchaserHunter vs EmailchaserFree tools
All free toolsBulk Email VerifierDeliverability TestEmail Header AnalyzerSMTP Settings FinderCold Email TemplatesBoolean Search BuilderAudience Size CalculatorName SplitterCompany Email FormatSpam Word CheckerInternational
Cold email (ES)Cold email (FR)Cold email (DE)Cold email (IT)Cold email (PT)Verifica email (IT)© Copyright 2026 Emailchaser