How much does Customer.io cost?

Customer.io's entry-level Essentials plan starts at $100 per month and includes 5,000 profiles and 1 million emails per month. Billing is based on the maximum number of uniquely identified profiles in the account during the month, with overage charges of roughly $0.009 per additional profile and $0.12 per 1,000 emails beyond plan limits. The Premium plan starts around $1,000 per month on an annual contract and adds managed deliverability, dedicated IPs, and HIPAA compliance with a signed BAA, while Enterprise pricing is custom.

What SDKs and languages does OneSignal support?

OneSignal provides official server SDKs for Node.js, Python, Java, Go, PHP, Ruby, C#, and Rust, all generated from the same OpenAPI specification for a consistent interface. It also offers a REST API and client SDKs for mobile and web. This makes it straightforward to send email and other channels from most common backend stacks.

Can I use Customer.io and OneSignal Email together?

Yes. Many teams route different message types through different providers or fail over between them. Courier lets you send through both behind a single API and switch providers without changing your code.

Customer.io vs OneSignal Email

Two transactional email providers, compared on price, features and ratings, so you can pick fast.

Customer.io wins developer experience and sending APIsOneSignal Email wins price

Updated September 2026

At a glanceCustomer.ioOneSignal Email

Cost per 1k @ 100k—$1.39

G2 rating4.44.7

Trustpilot3.22.6

Drag-and-drop editorYesYes

THE VERDICT

Customer.io wins on developer experience and sending APIs. OneSignal Email wins on price.

Customer.io and OneSignal Email take different pricing approaches. OneSignal Email rates higher with developers (4.7 vs 4.4 on G2). Pick based on volume and team, and the scorecard below breaks down where each one leads.

Which should you choose?

Pick Customer.io

✓You need behavior-triggered lifecycle messaging across email, push, and SMS

✓You want journeys driven by real-time user/event data and a unified profile

✓You're consolidating marketing automation and transactional messaging

✓You need EU data residency or HIPAA-grade compliance

Pick OneSignal Email

✓You already use OneSignal for push or in-app and want to add email from the same dashboard

✓You want a free tier to start sending marketing or transactional email

✓You need to manage subscribers across push, in-app, and email in one place

✓You want a simple setup rather than a dedicated deliverability or template platform

Set up OneSignal Email with Courier →

Feature by feature

Winner cells are tinted, green where Customer.io leads, violet where OneSignal Email does.

capability

Customer.io

OneSignal Email

Pricing

Starting paid plan

$100/mo

$19/mo

Cost per 1k @ 100k

—

$1.39

Pricing model

Subscription

Hybrid

Overage

Profile-based pricing: additional profiles $0.009 each; additional emails $0.12 per 1,000 over the plan's bundled allowance; AI credits $10/100K. Email volume does not map to a per-email tier.

$1.50 / 1,000 sends

Deliverability

Dedicated IP

Plan-gated

Deliverability tooling

Yes

Automated IP warmup

Yes

Suppression management

Yes

SPF / DKIM / DMARC

Yes

API & sending

Transactional API

Yes

Marketing campaigns

Yes

SMTP relay

Yes

—

Inbound routing

—

Dynamic templates

Yes

Batch send

Yes

Scheduled send

Yes

Developer experience

Official SDKs

Ruby, Python, Node.js, Go, PHP, JavaScript (Web), iOS, Android, React Native, Flutter, Expo

Node.js, Python, Java, Go, PHP, Ruby, C#, Rust

Event webhooks

Yes

Drag-and-drop editor

Yes

Custom HTML editor

Yes

Email validation

—

Analytics

Open / click tracking

Yes

Analytics dashboard

Yes

A/B testing

Yes

Compliance

EU data residency

Yes

—

SOC 2

Yes

HIPAA

BAA

GDPR

Yes

ISO 27001

Yes

Support

Support channels

Community + email (Essentials); chat (Standard); dedicated CSM + technical specialist (Premium/Enterprise)

Email, Community

24/7 support

—

Yes

Support SLA

Plan-gated

Migration assistance

Yes

—

FAQ

Common questions

OneSignal Email rates higher on G2 (4.7 vs 4.4). Ratings are aggregated from public review platforms as of the date shown.

Keep comparing

Related comparisons

Customer.io vs PostmarkEmail→Customer.io vs MailgunEmail→Customer.io vs SendGridEmail→AWS SES vs Customer.ioEmail→Customer.io vs SparkPostEmail→Customer.io vs MailjetEmail→

Why not both?

Use both behind one API.

Route Customer.io, OneSignal Email, or both, and switch providers without changing your code. Courier sits in front of every channel.

Start building free Read the docs

Pricing, plans and feature availability as of September 2026 and may change. Ratings are aggregated from public review platforms.