Email APIs · side by side
Klaviyo vs UniOne
Compare Klaviyo, UniOne 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.
Klaviyo
UniOne
Klaviyo
Custom / not listed
Custom / unlisted usage pricing · 10K profiles
UniOne
$0 / mo
Free Trial · 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 | Klaviyo | UniOne |
|---|---|---|
| Provider | Klaviyo | ECOMZ Holding Limited |
| Billing unit | profiles | emails |
| Plan at selected usage | Custom / unlisted usage pricing | Free Trial |
| Monthly estimate | Custom / not listed | $0/mo |
| Workload | 10K profiles | 0 emails |
| Free access | Limited free plan | 4-month free trial with 6,000 emails/month and 100 email validations; free testing tier allows up to 100 emails/day to v |
| Published plans | Free | Free Trial, Standard, Individual |
| Prices checked | 2026-10-08 | 2026-10-08 |
- Klaviyo
- Klaviyo
- UniOne
- ECOMZ Holding Limited
- Klaviyo
- profiles
- UniOne
- emails
- Klaviyo
- Custom / unlisted usage pricing
- UniOne
- Free Trial
- Klaviyo
- Custom / not listed
- UniOne
- $0/mo
- Klaviyo
- 10K profiles
- UniOne
- 0 emails
- Klaviyo
- Limited free plan
- UniOne
- 4-month free trial with 6,000 emails/month and 100 email validations; free testing tier allows up to 100 emails/day to v
- Klaviyo
- Free
- UniOne
- Free Trial, Standard, Individual
- Klaviyo
- 2026-10-08
- UniOne
- 2026-10-08
Email APIs monthly cost
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.
Which email providers fit your needs?
Klaviyo features & plan notes
- E-commerce data
- Omnichannel
- Shopify ecosystem
UniOne features & plan notes
- Email delivery via RESTful Web API and SMTP API
- Dynamic templating supporting Liquid, Velocity, and Simple template engines
- Drag-and-drop email builder with AI HTML editor and 200+ pre-built templates
- Real-time event webhooks, click/open tracking, and up to 100 days of analytics storage
- Integrated email validation API and automatic suppression list management
- All features of the STANDARD PLAN
- 4 months with 6,000 monthly emails
- 100 email address validations included
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