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 forever	Free 1,000 emails / mo	Flat · 1,000 emails / mo	Standalone · Free
Pay as you grow	USD 0 per email $0.001 / email	Usage · 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 forever

Highlights No credit card required: 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

Pay as you grow

Highlights Everything in Free: Included
Highlights No Plunk branding: Included
Highlights Monthly spend cap: Included
Highlights Unlimited emails: Included

How their prices changed

Each date shows when a public price was observed, not when it took effect. An archived region or currency can differ, so a currency change is not necessarily a price increase.

Customer.io

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

Plunk

September 21, 2026
Official pricing page
- Free forever: Free
- Pay as you grow: USD 0 per email
August 27, 2026
Official pricing page
- Free — Free: Free
- Paid — Pay as you grow: $0.001 per email