Knock vs Postmark (2026): which should you pick?

Pick Knock if

• Fits if you're a product team and want one workflow to reach email, in-app and chat
• Works for apps that already have an email provider and need preferences and batching on top

Look elsewhere if

• Skip it if you want a service that sends email by itself: it needs a provider you connect
• Pricey if you outgrow free, because the next step is $250 a month
• Tight if you want the Knock branding gone, as that needs Starter or higher
• Watch out: email client previews, SAML SSO, SCIM and translations sit on dearer plans, and the HIPAA BAA is Enterprise only

Pick Postmark if

• Fits if you want password resets kept on a separate stream from your newsletters
• Works for apps that need to look back at exactly what an email said weeks later

Look elsewhere if

• Pricey if you send 50,000 emails a month, at $55 with no yearly discount
• Skip it if you want a free plan to run a small app on, as it's 100 emails a month with no tier until 10,000
• Tight if you're on Basic, with 4 users, 5 sending domains and no inbound email
• Not for you if you want a dedicated IP below 300,000 emails a month, and each one is $50 a month on Pro or higher
• Watch out: DMARC reports are an add-on from $14 a month per domain

Knock

• Knock is an orchestration layer, so email delivery goes through a provider you connect; it is not a standalone sending service.
• The jump from Free to Starter is $250 a month, with messages beyond 50,000 billed at $0.005 each.
• Removing Knock branding, email client previews and priority email support need Starter or higher.
• Custom roles, SAML SSO, SCIM, translations and the HIPAA BAA are listed on Enterprise only.

Postmark

• There is no tier between the free 100 emails a month and the 10,000-email paid plans.
• Billing is monthly only; the FAQ says annual plans are not offered yet.
• Basic has no inbound email processing and caps users at 4 and sending domains at 5.
• Dedicated IPs start at $50 a month per IP, need Pro or higher and 300,000 emails a month or more.

Knock

Cross-channel workflows

A workflow is a single type of message, such as a user invite, that can branch, delay and route across email, in-app, push, SMS and chat.

Broadcasts and in-app guides

Broadcasts send a one-time message to an audience on any channel. In-app guides cover banners, modals, cards and tooltips rendered with your own components.

Batching and preferences

Batch and digest notifications to cut frequency, and let recipients manage preferences by channel, notification and category.

Email through your own provider

The integrations list names email providers including SendGrid, Postmark, Amazon SES, Mailjet, Mailgun, Mailtrap and MailerSend.

Agent and MCP access

Workflows, templates, guides, broadcasts and audiences can be managed from Claude, ChatGPT, Cursor and Slack, through a remote MCP server or the Knock CLI.

Multi-tenancy

Built-in multi-tenancy is listed on every plan, and per-customer branding and preferences on Enterprise.

Postmark

Email API and SMTP

Send through a REST API with official SDKs or through SMTP, with batch sending, a sandbox mode and migration guides from other providers.

Message streams

Transactional and bulk or broadcast email run on separate sending infrastructure, so marketing sends do not affect password resets and receipts.

Inbound email processing

Pro and Platform turn incoming email into a JSON object and post it to a webhook URL your app handles.

Templates

Responsive templates for welcome emails, password resets and receipts, with a template editor and import tool.

Message history and analytics

45 days of full message content by default, adjustable from 7 to 365 days, with bounce details, open and link tracking and a stats API.

DMARC monitoring

DMARC Digests reports show authentication problems and who is sending with your domain, sold as an add-on from $14 a month per domain.

Knock

• Free$0

  Up to 10,000 messages sent, 500 guide recipients and 500 agent credits each month. No credit card required.

• Starter$250

  per month, plus additional usage

  Includes 50,000 messages (then $0.005 each), 2,500 guide recipients and 2,000 agent credits. Removes Knock branding; adds email client previews.

• EnterpriseCustom

  Annual agreements with volume-based pricing, custom roles, SAML SSO, SCIM, enterprise SLAs, HIPAA BAA and priority support over Slack, email and calls.

Postmark

• Free$0

  100 emails a month, never expires; extra emails cannot be bought on this plan.

• Basic$15

  per month for 10,000 emails

  5 sending domains, 4 users, 45 days of history, no inbound email. Extra emails $1.80 per 1,000; $55 a month at 50,000 emails.

• Pro$16.50

  per month for 10,000 emails

  10 domains, 6 users, inbound email, retention up to 365 days. Extra emails $1.30 per 1,000; $60.50 a month at 50,000 emails.

• Platform$18

  per month for 10,000 emails

  Unlimited domains, servers, streams and users, with inbound email. Extra emails $1.20 per 1,000; $66 a month at 50,000 emails.

• High volumeCustom

  Custom pricing for large senders, arranged through sales.

Knock

No public discounts listed.

Postmark

• Startups

  $75 credit for bootstrapped companies

  Companies that have launched, are charging for their product and have taken no outside investment can ask support for $75 of account credit.