> This page is part of the [Customer.io documentation](https://docs.customer.io). For the complete index, see [llms.txt](https://docs.customer.io/llms.txt).
> Last updated: July 15, 2026

# Builder plan: pay-as-you-go

The Builder plan gives early-stage builders, transactional senders, and AI coding agents messaging infrastructure: set up for free, and go live for $10 when you’re ready.

## How it works

The Builder plan is a low-cost way to set up and start sending [transactional messagesMessages that your audience implicitly opts into—like purchase receipts, password reset requests, shipping updates, two-factor authentication codes, etc.](/journeys/send/transactional/api/) and one-time broadcasts with Customer.io. If you’re looking for an email platform, transactional email, or messaging infrastructure for an app, Builder is the Customer.io plan to start with. You can send emails, push notifications, in-app messages, and webhooks via our CLI, MCP server, or web app. You can also send [SMS](/messaging/channels/sms/get-started/#set-up-sms-through-twilio) and [WhatsApp](/messaging/channels/whatsapp/get-started/#set-up-twilio) if you integrate with Twilio.

Unlike our other offerings, the Builder plan is not a subscription model and has no monthly fees and no trial period. It’s free to build and test!

When you’re ready to send to your customers, you add funds, starting at just $10, and pay $0.40 per 1,000 messages.

To create marketing automations or set up out-of-the-box integrations with services like Salesforce, check out our [subscription-based plans](https://customer.io/pricing/) instead.

### Who is the Builder plan for?

Anyone can sign up for the Builder plan, but it’s intended for:

*   **Developers and founders at startups** in the early stages who need reliable transactional messaging and aren’t yet ready to sign up for a monthly plan.
*   **Mobile developers** who want to test push notifications and in-app messages before committing to a monthly plan.
*   **AI-native builders** working with LLMs, coding agents, and other tools who want messaging as infrastructure. You don’t need a GUI; you use our CLI to support your workflows.

 If you need behavioral workflows, audience segmentation, or multi-channel automation, start with the [Essentials plan](https://customer.io/pricing/).

### What’s included in the Builder plan

The Builder plan includes the following features. Those not included are available on our [Essentials and higher plans](https://customer.io/pricing/).

Workflows

Available in Builder Plan

[Transactional messagesMessages that your audience implicitly opts into—like purchase receipts, password reset requests, shipping updates, two-factor authentication codes, etc.](/journeys/send/transactional/api/)

[Broadcasts](/get-started/send-messages/#one-time-sends) (One-time sends only)

[API-triggered broadcasts](/get-started/send-messages/#api-triggered-broadcasts)

[Automations](/get-started/send-messages/#automations)

Message channels

Available in Builder Plan

Details

Email

Send for free to up to 10 [verified recipients](#add-test-users) before sending to customers. Up to 2 sending domains per workspace.

Push notifications

[In-app messages](/messaging/channels/in-app/send-in-app-message/)

[Inbox messages](/messaging/channels/in-app/inbox/get-started/)

Webhooks

[SMS](/get-started/set-up-messages/#set-up-smsmms) or [WhatsApp through Twilio](/messaging/channels/whatsapp/get-started/#set-up-twilio)

SMS or WhatsApp through direct integrations

LINE

Slack

Anonymous in-app messages

Data and integrations

Available in Builder Plan

Details

[Profiles](/get-started/add-profiles/)

Add verified, test recipients and customers to your workspace.

[Manual segmentsA segment of people you maintain manually. You must explicitly add people to, or remove people from, the segment.](/journeys/segmentation/manual-segments/)

[Dynamic, data-driven segments](/get-started/segments-and-profiles-data/#data-driven-segments)

[Custom objectsAn object is a non-person entity that you can associate with one or more people—like a company, account, or online course.](/journeys/objects-data/objects/)

Web & mobile SDKs and libraries

Native integrations for services like Salesforce or Hubspot

Analytics across workflows and message channels

## Set up & test your account

If you’re new to Customer.io, you can [sign up for the Builder plan here](https://fly.customer.io/signup?signupType=builder) or through [our CLI](/ai/cli/get-started/).

You can sign up without payment information and start setting up your message channels and integrations right away.

### Start with an AI coding agent

If you’re working in Claude Code, Codex, Cursor, Windsurf, or another terminal-based coding agent, install the Customer.io CLI and its skill in your project:

1.  Install the CLI:
    
    ```bash
    npm install -g @customerio/cli
    ```
    
2.  Install skills:
    
    ```bash
    cio skills install
    ```
    
3.  Tell your agent: `Set up Customer.io for this project using cio.`
    

The skill helps you sign up or sign in, wire up your project to send data to Customer.io, and set up your domain to send messages.

### Authenticate via CLI

If you signed up through our CLI, you’ll already have a key and can skip this step.

If you signed up through our site, go to *Home* in your workspace to create a *Service Account API key*.

Learn more about [getting started with our CLI](/ai/cli/get-started/).

### Set up your message channels

If you plan to send emails, add your sending domain to your workspace to start the verification process. Your domain must be verified to send emails to anyone, including your [verified recipients](#add-test-users).

Otherwise, you can set up other message channels through our CLI or [Workspace Settings](https://fly.customer.io/workspaces/last/settings).

### Add verified recipients

Verified recipients are test users that have opted into receiving emails from you. You can add up to 10 verified recipients to your workspace. Account Admins are automatically added as verified recipients.

Verified recipients are only available on the Builder plan.

#### Add recipients from *Home*

When you add a verified recipient from *Home*, this profile automatically receives an email asking them to opt-in to receiving emails. You can’t send to verified users until they’ve opted in.

#### Add recipients from the Profiles page

You can also add individuals or groups of profiles via CSV from the Profiles page.

After you add profiles, select each profile you want to verify. Then choose **Actions > Invite verified recipient** to send them an opt-in confirmation email.

#### Check opt-in status

To check whether your verified recipients have opted-in to receiving emails, review their profile:

1.  Go to *Profiles*.
2.  Search for and select your recipient.
3.  Check *Verified user status*. `Pending` means they have not opted in yet. `Verified` means they have opted in and can now receive emails.

### Send to verified recipients

Send emails to verified recipients to check how your emails look before going live. Your sending domain must be verified before you can send to anyone, including verified recipients.

## Send to customers: add funds

When you’re ready to send to your customers, you purchase funds to go live. Funds don’t expire, and you can track usage from *Home* or your [Plans & Billing page](https://fly.customer.io/settings/billing/your-plan).

Details

**Minimum purchase**

$10 (~25,000 sends)

**Maximum funds per purchase**

$1,000

**Cost**

$0.40 per 1,000 messages

**Message rate**

Flat across all channels—email, in-app, push, webhooks, and SMS or WhatsApp through Twilio

**Profiles**

Unlimited person profiles, no objects

1.  Click **Add funds**.
2.  Enter your payment information and the amount you want to purchase.

The minimum purchase is $10, and you can add funds at any time.

 Sending stops when your funds run out

When your funds run out, sending stops and you need to add funds manually. We’ll email your Account Admins when you’re low on funds so you know to take action.

## Sending limits for new accounts

New accounts on our “builders” plan start with a daily sending limit that increases automatically as you build a healthy sending history. You don’t need to request an increase; most senders never reach it. See [Sending limits for new accounts](/accounts/billing/plan-features/#new-account-sending-limits) for more information.

## Manage your plan

If you’re new to Customer.io, you can [sign up for the Builder plan](https://fly.customer.io/signup?signupType=builder). Otherwise, learn more about upgrading and downgrading below.

You can upgrade to Essentials or higher by reaching out to our team at [win@customer.io](mailto:win@customer.io).

When you upgrade, everything you’ve built carries over—your message channels, profiles, and content. No migration is required.

To downgrade from another plan, you’ll also reach out to our team at [win@customer.io](mailto:win@customer.io).

*   *   [How it works](#how-it-works)
        *   [Who is the Builder plan for?](#who-is-the-builder-plan-for)
        *   [What’s included in the Builder plan](#whats-included-in-the-builder-plan)
    *   [Set up & test your account](#set-up--test-your-account)
        *   [Start with an AI coding agent](#start-with-an-ai-coding-agent)
        *   [Authenticate via CLI](#authenticate-via-cli)
        *   [Set up your message channels](#set-up-your-message-channels)
        *   [Add verified recipients](#add-test-users)
            *   [Add recipients from *Home*](#add-recipients-from-home)
            *   [Add recipients from the Profiles page](#add-recipients-from-the-profiles-page)
            *   [Check opt-in status](#check-opt-in-status)
        *   [Send to verified recipients](#send-to-verified-recipients)
    *   [Send to customers: add funds](#send-to-customers-add-funds)
    *   [Sending limits for new accounts](#new-account-sending-limits)
    *   [Manage your plan](#manage-your-plan)

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