Customer.io vs Plunk

See how their public offers line up before you choose your own position. Prices stay in the currency, billing schedule, and charged unit each vendor publishes.

Customer.io

See full pricing history

USD · US · source: customer.io

Plan	Pricing	Charged by	Offer type
Essentials	USD 100 monthly Starts at $100/month billed monthly	Flat · per month	Standalone · Starting at
Premium Highlighted	USD 1000 / month with annual commitment Starts at $1,000/month billed yearly	Flat · per month	Standalone · Starting at

Plunk

See full pricing history

USD · US · source: www.useplunk.com

Plan	Pricing	Charged by	Offer type
Free — Free	Free Free forever 1,000 emails per month	Flat · 1,000 emails / mo	Standalone · Free
Paid — Pay as you grow Highlighted	$0.001 per email $0.001 per email	Usage · $0.001 per email	Standalone · Usage based

What each plan includes

Feature names follow each vendor’s own pricing page, so verify the wording before treating them as exact equivalents.

Customer.io

Essentials

Plan card Profiles: 5,000

Included
Plan card Emails: 1 million/month

Included
Plan card Visual workflow builder: Included

Premium

Plan card Unlimited workspaces: Included
Plan card Advanced governance: Included
Plan card Dedicated implementation support: Included

Plunk

Free — Free

Highlights Emails per month: 1,000 emails

Included
Highlights Credit card required: No

Included
Highlights Transactional emails: Included
Highlights Workflow automation: Included
Highlights Campaign broadcasts: Included
Highlights Custom domains: Included
Highlights Click & open tracking: Included
Highlights Unlimited contacts: Included
Highlights Plunk branding on emails: Included

Paid — Pay as you grow

Highlights Emails per month: Unlimited emails

Included
Highlights Plunk branding on emails: No

Excluded
Highlights Monthly spend cap: Yes

Included

How their prices changed

Each dated row shows the public prices observed when that vendor’s pricing page changed.

Customer.io

August 27, 2026 Source
- Essentials: USD 100 monthly
- Premium: USD 1000 / month with annual commitment

Plunk

August 27, 2026 Source
- Free — Free: Free
- Paid — Pay as you grow: $0.001 per email