Posteo SMTP Settings
German green-powered mail with one server name, posteo.de, and no custom domains.
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Outgoing mail (SMTP)
SMTP server
posteo.de
Port. STARTTLS
587
Port. SSL/TLS
465
Security
STARTTLS on 587 (recommended) or SSL/TLS on 465.
Incoming mail (IMAP)
IMAP server
posteo.de
Port. SSL/TLS
993
Port. STARTTLS
143
Incoming mail (POP3)
POP3 server
posteo.de
Port. SSL/TLS
995
Port. STARTTLS
110
Sending limits & login
Daily send limit
Fair-use limits apply; Posteo is a personal mailbox, not a bulk sender.
Authentication
Sign in with your full Posteo address and your account password. All three protocols share the single host posteo.de.
App password
No app password. If two-factor auth is on, use the app-specific password set in Posteo's settings.
SMTP, IMAP and POP3 all run on the same hostname: posteo.de.
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Posteo SMTP, IMAP and POP3 settings
Posteo is a small German provider funded only by its users, with no custom domains and no free plan. Whatever your address ends in, posteo.de, posteo.net or posteo.com, the server name you type into a mail app is always plain posteo.de. Posteo also lets you switch on additional email account protection, which stops your normal password from working over IMAP, POP3 and SMTP.
For incoming mail, use the IMAP server posteo.de on port 993, or POP3 at posteo.de on port 995. Pick the exact values from the tool above and copy them straight into your mail client.
Checked against Posteo's own documentation: posteo.de. Ports and limits change, so check there too if something will not connect.
Posteo 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 Posteo username and password
Wrong credentials, not a wrong port, are the usual reason a Posteo connection fails. These are the exact values to type.
Your full Posteo address, for example yourname@posteo.de
Your Posteo password, or an app password you choose yourself. An app password is compulsory once additional email account protection is active.
How to set up Posteo in a mail client
The exact path through Posteo's own settings, in order.
- 1
Pay for the account first
Posteo's terms state that until the first payment has been made, the customer can only send 10 emails within a two hour period.
- 2
Create an app password if you want one
In webmail open Settings, click My account, open Password and security, and in the App passwords (device passwords) section click Create app password.
- 3
Pick a password that meets Posteo's rules
An app password must be at least 16 characters and contain at least one number and one upper-case letter. You can hold up to five at once, and you may type your own into the App password field instead of the suggested one.
- 4
Enter the incoming server
Server name posteo.de. IMAP is port 993 with SSL/TLS or port 143 with STARTTLS; POP3 is port 995 with SSL/TLS or port 110 with STARTTLS.
- 5
Enter the outgoing server
Server name posteo.de, SMTP port 465 with SSL/TLS or port 587 with STARTTLS. Set the authentication method to normal or plain.
- 6
Optionally lock out your main password
Under Settings > My account > Password & security, activate additional email account protection so IMAP, POP3 and SMTP accept app passwords only.
What Posteo looks like filled in
Every mail client asks for the same handful of fields. Here they are with Posteo's values already in place.
Account settings: Posteo
Server
posteo.dePort
587Encryption
STARTTLSAuthentication
RequiredUsername
Your full Posteo address, for example yourname@posteo.dePassword
Your Posteo password, or an app password you choose yourself. An app password is compulsory once additional email account protection is active.Server
posteo.dePort
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.
Posteo SMTP settings in Thunderbird
The outgoing server dialog with Posteo's details entered. Outlook and Apple Mail ask for the same four things under slightly different names.
Which port should you use for Posteo?
STARTTLS on 587 (recommended) or SSL/TLS on 465.
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 Posteo connection is failing
The failures people actually hit with Posteo, and what fixes each one.
Additional email account protection has been switched on, which blocks the normal Posteo password over IMAP, POP3 and SMTP. Create an app password under Settings > My account > Password and security and use that.
Using Posteo's forgotten password flow deletes all your app passwords. Changing the password normally from inside account settings leaves them working, so prefer that route.
Posteo accepts encrypted connections only and refuses obsolete TLS versions. A client that tops out at TLS 1.1 or older cannot sync, so the software has to be updated or replaced.
Posteo blocks .exe, .vbs, .pif, .scr, .bat, .cmd, .com, .cpl and .dll, including inside archives. Send the file through a file transfer service instead.
Posteo has no per-protocol hostnames. The server name is plain posteo.de for IMAP, POP3 and SMTP, whichever Posteo domain your address uses.
Posteo sending limits
The hourly and daily figures come from Posteo's terms of service; before the first payment the account is held to 10 emails per two hours. Posteo's own pages disagree on attachments: the features page says 100 MB each way, while the terms of service still say 50 MB, so treat 50 MB as the safe number.
Per day
1,000 emails
Per hour
500 emails
Max attachment
100 MB sending and 100 MB receiving
Posteo quirks by mail client
Thunderbird
Set the authentication method to Normal password, which matches the normal or plain login Posteo documents.
Sending cold email through Posteo
Fair-use limits apply; Posteo is a personal mailbox, not a bulk sender. Sign in with your full Posteo address and your account password. All three protocols share the single host posteo.de.
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 Posteo accounts.
Other consumer email providers
Setting up more than one mailbox? These sit in the same category as Posteo.
Common questions about Posteo SMTP settings
What are Posteo's SMTP settings?
Posteo's outgoing (SMTP) server is posteo.de. Use port 587 (STARTTLS) or 465 (SSL/TLS). STARTTLS on 587 (recommended) or SSL/TLS on 465. Sign in with your full email address and password (or app password).
What is Posteo's IMAP or POP3 server?
Posteo's incoming IMAP server is posteo.de on port 993 (SSL/TLS). If you prefer POP3, use posteo.de on port 995.
Which port should I use for Posteo?
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. Posteo's recommended value is above.
Why won't my Posteo SMTP connection work?
Check authentication first: Sign in with your full Posteo address and your account password. All three protocols share the single host posteo.de. No app password. If two-factor auth is on, use the app-specific password set in Posteo's settings. 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 Posteo?
Not at scale. Fair-use limits apply; Posteo is a personal mailbox, not a bulk sender. 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.
I have a @posteo.net address. Do I use posteo.net as the server?
No. Posteo runs one set of servers, and the server name is posteo.de for IMAP, POP3 and SMTP no matter which Posteo domain your address uses. Only the username changes.
Do I have to use an app password with Posteo?
Not by default, they are an optional feature. But once you activate additional email account protection they become the only thing a mail app can log in with. Unusually, you pick the app password yourself: at least 16 characters with a number and a capital letter, up to five at a time.
Can I use my own domain with Posteo?
No. Posteo only issues addresses on its own domains such as posteo.de, posteo.net and posteo.com. You get three alias addresses included and can buy up to 25 for 0.10 EUR each per month, but a custom domain means choosing a different provider.
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