HubSpot SMTP Settings and Configuration (2026)
HubSpot Marketing Hub does not include SMTP — requires the Transactional Email add-on
HubSpot Marketing Hub (Free, Starter, Professional, Enterprise) is broadcast-only for marketing emails. To send transactional email (order confirmations, password resets, receipts) from HubSpot, you must purchase the Transactional Email add-on, which unlocks a dedicated sending IP and both API + SMTP relay access. The add-on starts around $150-450/mo depending on volume and is available only on paid Marketing Hub or Sales Hub tiers.
Unlike Klaviyo or Constant Contact (which have no SMTP at all), HubSpot offers a legitimate transactional path — but at a premium. If you already run HubSpot for marketing + CRM and want unified vendor billing, the Transactional Email add-on makes operational sense. If you only need SMTP relay standalone, Postmark, Mailgun, or Brevo deliver equivalent quality at a fraction of the cost. HubSpot Transactional Email is best suited for enterprise buyers who value the CRM contact integration for transactional messages.
Quick reference
The essential HubSpot Transactional Email SMTP settings once you have added the paid add-on. Applies to the Transactional Email add-on only — not the base Marketing Hub product.
| Add-on required | Transactional Email (paid, ~$150-450/mo) |
|---|---|
| SMTP server | Provided per-account by HubSpot after add-on activation |
| Port (STARTTLS) | 587 |
| Authentication | SMTP API key (generated per SMTP token in HubSpot UI) |
| Username | Auto-generated per SMTP token |
| Password | SMTP API key (shown once at token creation) |
| Alternative: HTTP API | Single-send transactional API endpoint (requires Marketing Hub Pro + add-on) |
| Dedicated IP | Included in the add-on |
SMTP configuration (with Transactional Email add-on)
Outgoing mail server (HubSpot Transactional add-on)
— requires paid add-on activation
Setup steps
- Confirm you have a paid Marketing Hub or Sales Hub tier (Starter or higher) and purchase the Transactional Email add-on.
- Once activated, navigate to Settings › Marketing › Email › Transactional. Complete the domain authentication wizard (DKIM + SPF).
- Create an SMTP API token under the same section. Name it descriptively (e.g.,
wordpress-transactional). Copy the generated username + password immediately. - In your email client or WP SMTP plugin, enter the assigned SMTP host, port 587, encryption
STARTTLS, authLOGIN. - Username = the SMTP API token username. Password = the SMTP API token password.
- Send a test email. Check the HubSpot Transactional Email dashboard for delivery status and any auth or bounce errors.
Authentication
HubSpot Transactional Email SMTP uses LOGIN authentication with per-token credentials. Each SMTP API token issued under your account has a unique username + password pair — not tied to your main HubSpot API keys or private app tokens.
- Per-token isolation: generate multiple SMTP tokens for different integrations. Revoke individually without breaking others.
- Separate from Marketing API keys: the SMTP token is NOT the same as your HubSpot API key or private app token. They authenticate different systems.
- Dedicated IP included: the Transactional add-on assigns a dedicated sending IP. Warmup and reputation management are handled by HubSpot’s deliverability team.
- DKIM auto-signed: once your sending domain is authenticated via HubSpot’s wizard, DKIM signing is automatic on all transactional sends.
Domain authentication (SPF, DKIM, DMARC)
Complete domain authentication under Settings › Marketing › Email › Transactional › Domain. HubSpot generates the DKIM record and provides SPF include values. Propagation typically completes in 1-4 hours after DNS publication.
DKIM record
HubSpot generates a domain-scoped DKIM TXT record. Publish it at the selector HubSpot assigns. Once verified, HubSpot signs every outbound transactional message with DKIM using your domain.
SPF record
Add include:_spf.hubspot.com (or the specific include HubSpot provides in your setup wizard) to your existing SPF record. If your Marketing Hub already sends broadcasts, the SPF may already be published. Never publish two separate v=spf1 TXT records.
DMARC alignment
DMARC is strongly recommended given Gmail/Yahoo/Microsoft bulk-sender rules in force since February 2024. HubSpot supports strict DMARC alignment on both SPF and DKIM when your domain is properly authenticated. Publish a DMARC TXT at _dmarc.yourdomain.com with a rua reporting address.
Rate limits & sending caps
| Limit type | Value | Notes |
|---|---|---|
| Transactional Email add-on entry tier | Volume-based, custom quote | Typical entry ~10K sends/mo included at $150/mo tier. |
| Volume scaling | Progressive tiers | $150/mo (10K), $250/mo (50K), $450/mo (100K+) as typical ranges. |
| Concurrent SMTP connections | Not disclosed | Reputation-based, managed by HubSpot deliverability team. |
| Recipients per message | Not disclosed | Standard SMTP conventions apply. Use batches for bulk sends. |
| Message size | 10 MB standard | Body + attachments combined. Larger via HubSpot support. |
| Dedicated IP included | Yes | Automatic warmup by HubSpot deliverability team. |
Common setup gotchas
SMTP relay requires the Transactional Email paid add-on
Base HubSpot Marketing Hub (Free, Starter, Professional, Enterprise) does NOT include SMTP relay. You must purchase the Transactional Email add-on separately (~$150-450/mo) AND you must be on paid Marketing Hub or Sales Hub (Starter or higher). Do not attempt to configure SMTP without the add-on activated.
SMTP API tokens are separate from Marketing API keys / private app tokens
HubSpot has multiple credential systems: API keys, private app tokens, OAuth tokens, and (with the add-on) SMTP API tokens. Only the SMTP API token works for SMTP relay authentication. Pasting a Marketing API key or private app token as your SMTP password will fail with 535 authentication failed.
Marketing emails and transactional emails have different sending rules
HubSpot enforces strict separation: marketing emails follow subscription and unsubscribe rules; transactional emails bypass those. Do not use the Transactional Email add-on for newsletter blasts — HubSpot will detect the pattern and pause the account. Use Marketing Hub for broadcasts, transactional add-on for triggered 1-to-1 messages only.
Port 25 is blocked on major cloud hosts
Standard cloud provider restriction. Use port 587 with STARTTLS as the default. HubSpot does not publish alternative ports.
Cost sensitivity: consider standalone SMTP if transactional is your primary need
The Transactional Email add-on starts at ~$150/mo on top of paid Marketing Hub (Starter from $20/mo). Total floor: ~$170/mo. If you only need SMTP relay for transactional traffic and do not use HubSpot Marketing, Postmark ($15/mo for 10K) or Brevo (Free 300/day) deliver equivalent quality at 5-10x lower cost.
Migrating SMTP setups
To HubSpot Transactional (from another provider)
Purchase the Transactional Email add-on, complete domain authentication in HubSpot, generate SMTP API tokens, and cutover your app SMTP config. Plan for 4-8 hours including add-on activation, DNS propagation, and reputation warmup coordination with HubSpot’s deliverability team. Keep the old provider active for 24 hours during cutover.
From HubSpot Transactional (to a cheaper standalone SMTP)
Postmark, Mailgun, Brevo, and Amazon SES all deliver equivalent SMTP quality at fractional cost. Common migration reason: transactional volume grew past the point where the HubSpot add-on premium made sense standalone. Plan for 2-4 hours to swap credentials, republish DNS SPF include, and warm up a new IP if applicable.
Frequently asked questions
Does HubSpot have SMTP relay?
Only via the paid Transactional Email add-on (~$150-450/mo depending on volume) on top of a paid Marketing Hub or Sales Hub tier (Starter from $20/mo minimum). Base HubSpot Marketing Hub (Free, Starter, Professional, Enterprise) does NOT include SMTP. If you only need standalone SMTP, cheaper alternatives like Postmark ($15/mo), Brevo (Free 300/day), or Mailgun offer equivalent quality at fractional cost.
What does the HubSpot Transactional Email add-on cost?
Volume-based, not publicly transparent. Community-reported ranges: ~$150/mo for approximately 10K sends/month entry, ~$250/mo for 50K/mo, ~$450/mo for 100K+/mo. Request an accurate quote from HubSpot sales specifying your expected monthly transactional volume.
Can I use HubSpot Marketing Hub Free for SMTP relay?
No. HubSpot Marketing Hub Free does not include SMTP relay. You must upgrade to a paid Marketing Hub or Sales Hub tier (Starter minimum) AND purchase the Transactional Email add-on. Total minimum cost: ~$170/mo (Starter $20/mo + Transactional add-on $150/mo).
What credentials do I use for HubSpot SMTP?
An SMTP API token generated under Settings › Marketing › Email › Transactional › SMTP API tokens (available only after Transactional add-on activation). Each token has a unique auto-generated username + password pair. NOT the same as your HubSpot API key or private app token — those authenticate different systems. Pasting a Marketing API key as SMTP password will fail with 535 authentication failed.
Does HubSpot Transactional include a dedicated IP?
Yes. The Transactional Email add-on includes a dedicated sending IP with automatic warmup managed by HubSpot’s deliverability team. No extra fee for the dedicated IP — it is bundled with the add-on.
Can I use the HubSpot Transactional add-on for marketing broadcasts?
No, and HubSpot enforces this. Marketing broadcasts must go through Marketing Hub (subject to subscription and unsubscribe rules). Transactional Email is for 1-to-1 triggered messages only (order confirmations, password resets, receipts). If HubSpot detects broadcast patterns on the transactional stream, they pause the account.
Does HubSpot support IMAP or POP3?
No. HubSpot (like every email service provider) is outbound-only. It sends emails to recipients but does not host an inbox for you to read via IMAP or POP3. Those protocols are for mailbox providers like Gmail, Yahoo, or your ISP.
This review follows our email infrastructure testing methodology. We disclose affiliate relationships in our editorial independence policy.
