Email APIs · side by side
Knock vs Mandrill
Compare Knock, Mandrill by sending volume, delivery webhooks, inbound email, domain limits and retention.
Email APIs pricing calculator
These providers bill in different units. Each estimate uses its own workload; there is no same-volume price winner.
Knock
0
Mandrill
0
Knock
$0 / mo
Developer · 0 messages
Mandrill
$0 / mo
Try for free · 0 emails
Listed USD plan fees and tracked usage only. Unlisted compute, transfer, extras, taxes and contract terms are excluded. Custom or unsupported plan usage is not estimated.
Email APIs overview & pricing
| Email APIs | Knock | Mandrill |
|---|---|---|
| Provider | Knock Labs, Inc. | Mailchimp |
| Billing unit | messages | emails |
| Plan at selected usage | Developer | Try for free |
| Monthly estimate | $0/mo | $0/mo |
| Workload | 0 messages | 0 emails |
| Free access | Developer plan includes up to 10,000 messages per month, 500 guide active users, and 500 AI agent credits. | Up to 500 free demo/test email sends to a verified domain for new users. |
| Published plans | Developer, Starter, Enterprise | Try for free, Transactional Email |
| Prices checked | 2026-10-08 | 2026-10-08 |
Provider
- Knock
- Knock Labs, Inc.
- Mandrill
- Mailchimp
Billing unit
- Knock
- messages
- Mandrill
- emails
Plan at selected usage
- Knock
- Developer
- Mandrill
- Try for free
Monthly estimate
- Knock
- $0/mo
- Mandrill
- $0/mo
Workload
- Knock
- 0 messages
- Mandrill
- 0 emails
Free access
- Knock
- Developer plan includes up to 10,000 messages per month, 500 guide active users, and 500 AI agent credits.
- Mandrill
- Up to 500 free demo/test email sends to a verified domain for new users.
Published plans
- Knock
- Developer, Starter, Enterprise
- Mandrill
- Try for free, Transactional Email
Prices checked
- Knock
- 2026-10-08
- Mandrill
- 2026-10-08
Email APIs monthly cost
Knock: $0Mandrill: $0
Different workloads, separate estimates
Separate transactional delivery from campaigns, outreach and agent inboxes. Compare monthly sends and daily caps; contacts, seats and inboxes are not sending allowances. Budget separately for dedicated IPs, validation and attachments.
Email APIs feature comparison
| Email APIs | Knock | Mandrill |
|---|---|---|
| Messages included | Up to 10,000 Upgrade for additional usage. | Not listed |
| Guide active users included | Up to 500 Upgrade for additional usage. | Not listed |
| AI agent credits included | 500 $.01 per additional credit. | Not listed |
| Notification channels | Unlimited | Not listed |
| Team members | Unlimited | Not listed |
| Recipients | Unlimited | Not listed |
| Power Knock with source events | Not listed | |
| Notification workflows | Unlimited | Not listed |
| Workflow triggers | Unlimited | Not listed |
| Intelligent cross-channel routing | Not listed | |
| Batching | Not listed | |
| Fetch from HTTP | Not listed | |
| Conditional sending | Not listed | |
| Scheduled workflows | Not listed | |
| Preferences | Not listed | |
| End-to-end testing | Not listed | |
| Email client previews | Not listed | |
| Non-user recipients | Not listed | |
| Manage via API & CLI | Not listed | |
| Translations (i18n) | Not listed | |
| Feeds per recipient | Unlimited | Not listed |
| Pre-built components (In-app feeds) | Not listed | |
| Bring your own components (In-app feeds) | Not listed | |
| Remove Knock branding | Not listed | |
| Feed retention | Unlimited | Not listed |
| Feed API | Not listed | |
| Custom feed filtering | Not listed | |
| Unlimited guides | Unlimited | Not listed |
| Guide ordering | Not listed | |
| Guide throttling | Not listed | |
| Pre-built components (In-app guides) | Not listed | |
| Bring your own components (In-app guides) | Not listed | |
| Per-tenant branding | Not listed | |
| Per-tenant preferences | Not listed | |
| Logs | Not listed | |
| Log retention | 30-day retention | Not listed |
| Engagement tracking | Not listed | |
| Stream observability data | Not listed | |
| Stream analytics to Segment | Not listed | |
| Stream analytics to data warehouse | Not listed | |
| Version control & history | Not listed | |
| Isolated environments | Unlimited | Not listed |
| Custom roles and permissions | Not listed | |
| Audit logs | Not listed | |
| Google SSO | Not listed | |
| Custom SSO | Not listed | |
| Directory sync (SCIM) | Not listed | |
| Template migration services | Not listed | |
| Uptime SLA | 99.9% | Not listed |
| Enterprise support | Not listed | |
| Dedicated infrastructure | Not listed |
Messages included
- Knock
- Up to 10,000 Upgrade for additional usage.
- Mandrill
- Not listed
Guide active users included
- Knock
- Up to 500 Upgrade for additional usage.
- Mandrill
- Not listed
AI agent credits included
- Knock
- 500 $.01 per additional credit.
- Mandrill
- Not listed
Notification channels
- Knock
- Unlimited
- Mandrill
- Not listed
Team members
- Knock
- Unlimited
- Mandrill
- Not listed
Recipients
- Knock
- Unlimited
- Mandrill
- Not listed
Power Knock with source events
- Knock
- Mandrill
- Not listed
Notification workflows
- Knock
- Unlimited
- Mandrill
- Not listed
Workflow triggers
- Knock
- Unlimited
- Mandrill
- Not listed
Intelligent cross-channel routing
- Knock
- Mandrill
- Not listed
Batching
- Knock
- Mandrill
- Not listed
Fetch from HTTP
- Knock
- Mandrill
- Not listed
Conditional sending
- Knock
- Mandrill
- Not listed
Scheduled workflows
- Knock
- Mandrill
- Not listed
Preferences
- Knock
- Mandrill
- Not listed
End-to-end testing
- Knock
- Mandrill
- Not listed
Email client previews
- Knock
- Mandrill
- Not listed
Non-user recipients
- Knock
- Mandrill
- Not listed
Manage via API & CLI
- Knock
- Mandrill
- Not listed
Translations (i18n)
- Knock
- Mandrill
- Not listed
Feeds per recipient
- Knock
- Unlimited
- Mandrill
- Not listed
Pre-built components (In-app feeds)
- Knock
- Mandrill
- Not listed
Bring your own components (In-app feeds)
- Knock
- Mandrill
- Not listed
Remove Knock branding
- Knock
- Mandrill
- Not listed
Feed retention
- Knock
- Unlimited
- Mandrill
- Not listed
Feed API
- Knock
- Mandrill
- Not listed
Custom feed filtering
- Knock
- Mandrill
- Not listed
Unlimited guides
- Knock
- Unlimited
- Mandrill
- Not listed
Guide ordering
- Knock
- Mandrill
- Not listed
Guide throttling
- Knock
- Mandrill
- Not listed
Pre-built components (In-app guides)
- Knock
- Mandrill
- Not listed
Bring your own components (In-app guides)
- Knock
- Mandrill
- Not listed
Per-tenant branding
- Knock
- Mandrill
- Not listed
Per-tenant preferences
- Knock
- Mandrill
- Not listed
Logs
- Knock
- Mandrill
- Not listed
Log retention
- Knock
- 30-day retention
- Mandrill
- Not listed
Engagement tracking
- Knock
- Mandrill
- Not listed
Stream observability data
- Knock
- Mandrill
- Not listed
Stream analytics to Segment
- Knock
- Mandrill
- Not listed
Stream analytics to data warehouse
- Knock
- Mandrill
- Not listed
Version control & history
- Knock
- Mandrill
- Not listed
Isolated environments
- Knock
- Unlimited
- Mandrill
- Not listed
Custom roles and permissions
- Knock
- Mandrill
- Not listed
Audit logs
- Knock
- Mandrill
- Not listed
Google SSO
- Knock
- Mandrill
- Not listed
Custom SSO
- Knock
- Mandrill
- Not listed
Directory sync (SCIM)
- Knock
- Mandrill
- Not listed
Template migration services
- Knock
- Mandrill
- Not listed
Uptime SLA
- Knock
- 99.9%
- Mandrill
- Not listed
Enterprise support
- Knock
- Mandrill
- Not listed
Dedicated infrastructure
- Knock
- Mandrill
- Not listed
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Which email providers fit your needs?
Knock features & plan notes
- Cross-channel workflow orchestration with batching, delays, and branch logic
- Prebuilt and headless UI components for in-app notification feeds
- Out-of-the-box user preference management and hosted preference centers
- Git-like commit and workflow promotion across environments with CLI and API support
- 10K messages (Includes messages sent from workflows and broadcasts)
- 500 guide active users (A user that sees at least one guide in the month)
- 500 AI agent credits (Credits consumed by AI agent function, then $.01 per credit)
- Unlimited notification workflows
- Unlimited broadcasts
- Unlimited delivery channels
- Unlimited team members
- Batch and delay notifications
- Built-in multi-tenancy
- SSO via Google
Mandrill features & plan notes
- Send transactional emails via REST API or SMTP credentials
- Sold in blocks of 25,000 emails with volume discounts from $20 down to $10 per block
- Inbound email processing and real-time event webhooks
- Custom domain whitelabeling, dedicated IPs, and rules engine
- Up to 500 free email sends to your verified domain
- Streamlined template editing with drag and drop builder
- Developer documentation, guides, and SDK repositories
- Connect AI coding assistant directly through first-party MCP server
How to compare email providers
Separate transactional delivery from campaigns, outreach and agent inboxes. Compare monthly sends and daily caps; contacts, seats and inboxes are not sending allowances. Budget separately for dedicated IPs, validation and attachments.
Browse Email APIs pricing