SparkPost SMTP Settings
Transactional relay now sold as Bird Email; its SMTP username is always SMTP_Injection.
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Outgoing mail (SMTP)
SMTP server
smtp.sparkpostmail.com
Port. STARTTLS
587
Port. SSL/TLS
465
Security
STARTTLS on 587 (recommended) or 2525, or SSL/TLS on 465.
Incoming mail (IMAP)
IMAP
Not supported. This is a send-only service.
Incoming mail (POP3)
POP3
Not supported by this provider.
Sending limits & login
Daily send limit
Set by your SparkPost plan.
Authentication
Use the literal username "SMTP_Injection" and paste an API key with the Send via SMTP permission as the password.
App password
Create the API key under Configuration > API Keys.
SparkPost is a send-only relay: there is no IMAP or POP inbox. EU accounts use smtp.eu.sparkpostmail.com.
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SparkPost SMTP, IMAP and POP3 settings
SparkPost was bought by MessageBird and is now sold under the name Bird Email, though the smtp.sparkpostmail.com endpoint is still documented and still takes mail. Every customer types the same username, the literal string SMTP_Injection, and the password is an API key that has to carry the Send via SMTP permission. Accounts created in Europe use a separate host, smtp.eu.sparkpostmail.com.
SparkPost is a send-only relay, so there's no IMAP or POP3 inbox. You only configure the SMTP server above. Use the tool to copy each value into your app or script.
Checked against SparkPost's own documentation: developers.sparkpost.com, bird.com. Ports and limits change, so check there too if something will not connect.
SparkPost 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 SparkPost username and password
Wrong credentials, not a wrong port, are the usual reason a SparkPost connection fails. These are the exact values to type.
SMTP_Injection (type it exactly; it is the same fixed string for every SparkPost account)
How to set up SparkPost in a mail client
The exact path through SparkPost's own settings, in order.
- 1
Get a sending domain to 'ready to send'
Add the domain at https://app.sparkpost.com/domains/list/sending. It is only ready once three records verify: DKIM, the return-path CNAME that also covers SPF, and a DMARC policy covering the domain. A registration left unverified for about 14 days is removed.
- 2
Create an API key with Send via SMTP ticked
Go to https://app.sparkpost.com/account/api-keys, or https://app.eu.sparkpost.com/account/api-keys for an EU account, and enable the Send via SMTP permission on the key.
- 3
Point your client at the right regional host
smtp.sparkpostmail.com for a US account, smtp.eu.sparkpostmail.com for an EU account. Port 587 with STARTTLS, or 2525 where 587 is blocked.
- 4
Type SMTP_Injection as the username
Enter it exactly, with that capitalisation and the underscore, and paste the API key as the password. The authentication method has to be AUTH LOGIN. On a subaccount the username becomes SMTP_Injection:X-MSYS-SUBACCOUNT=123, with the primary account's API key still as the password.
- 5
Match your From address to the verified domain
A From address on a domain that is not verified in the account is blocked by policy at send time.
What SparkPost looks like filled in
Every mail client asks for the same handful of fields. Here they are with SparkPost's values already in place.
Account settings: SparkPost
Server
smtp.sparkpostmail.comPort
587Encryption
STARTTLSAuthentication
RequiredUsername
SMTP_Injection (type it exactly; it is the same fixed string for every SparkPost account)Password
A SparkPost API key that has the Send via SMTP permission enabledIMAP / POP3
Not applicable. SparkPost sends only, so there is no inbox to configure.An 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.
SparkPost SMTP settings in Thunderbird
The outgoing server dialog with SparkPost's details entered. Outlook and Apple Mail ask for the same four things under slightly different names.
Which port should you use for SparkPost?
STARTTLS on 587 (recommended) or 2525, 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 SparkPost connection is failing
The failures people actually hit with SparkPost, and what fixes each one.
Your From address has to sit on a domain that is verified in the account, and a subdomain does not cover its parent: adding autos.example.com does nothing for sales@example.com. Add the exact domain and wait until DKIM, the return-path CNAME and DMARC all verify.
SparkPost requires STARTTLS and AUTH LOGIN, and the API key you send as the password must carry the Send via SMTP permission. Turn encryption on and reissue the key with that permission enabled.
EU accounts sit on separate infrastructure. Use smtp.eu.sparkpostmail.com and manage keys at app.eu.sparkpost.com instead.
SparkPost disconnects idle connections after 1 minute and asks senders to reuse a connection for at most 100 messages before reconnecting. Set your mailer to reconnect rather than hold one socket open.
Use port 2525, which SparkPost offers for exactly this situation and which its docs name Google Compute Engine as an example of.
SparkPost sending limits
SparkPost asks for at most 100 messages per connection, drops idle connections after 1 minute, and expects a per-command timeout of at least 60 seconds
Recipients per message
1,000 in total across the cc, bcc and archive lists combined
SparkPost servers by region and plan
SparkPost does not use one set of hostnames everywhere. Match the row to your account.
| Region or plan | SMTP | IMAP | POP3 |
|---|---|---|---|
| United States (default) | smtp.sparkpostmail.com | Not applicable | Not applicable |
| European Union | smtp.eu.sparkpostmail.com | Not applicable | Not applicable |
Sending cold email through SparkPost
Set by your SparkPost plan. Use the literal username "SMTP_Injection" and paste an API key with the Send via SMTP permission as the password.
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 SparkPost accounts.
Other smtp sending services
Setting up more than one mailbox? These sit in the same category as SparkPost.
Common questions about SparkPost SMTP settings
What are SparkPost's SMTP settings?
SparkPost's outgoing (SMTP) server is smtp.sparkpostmail.com. Use port 587 (STARTTLS) or 465 (SSL/TLS). STARTTLS on 587 (recommended) or 2525, or SSL/TLS on 465. Sign in with the SMTP credentials SparkPost issues you, not a mailbox address and password.
What is SparkPost's IMAP or POP3 server?
SparkPost is a send-only service, so it has no IMAP or POP3 inbox. You configure it as an outgoing SMTP server only.
Which port should I use for SparkPost?
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. SparkPost's recommended value is above.
Why won't my SparkPost SMTP connection work?
Check authentication first: Use the literal username "SMTP_Injection" and paste an API key with the Send via SMTP permission as the password. Create the API key under Configuration > API Keys. 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 SparkPost?
Not at scale. Set by your SparkPost plan. 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.
Is SparkPost the same thing as Bird now?
Yes. MessageBird acquired SparkPost and rebranded the product as Bird Email, and the old support pages now redirect to bird.com. The SMTP relay itself has not changed name: smtp.sparkpostmail.com is still what the developer documentation tells you to connect to.
Why is the SMTP username the same for everybody?
SMTP_Injection is a fixed literal, not an account identifier. SparkPost works out who you are from the API key you send as the password, so the username field carries no information. Typing your email address there will fail.
Do I need a different setup if my account is in the EU?
Yes, in two places. Connect to smtp.eu.sparkpostmail.com rather than smtp.sparkpostmail.com, and create your API key in the EU dashboard at app.eu.sparkpost.com. A key made in the US dashboard will not authenticate against the EU host.
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