subscriber.dev vs Customer.io

Customer.io is a full marketing platform with a visual journey builder and every channel. subscriber.dev does lifecycle email from your agent and terminal, for a fraction of the price.

## side by side

┌─────────────┬─────────────────────────┬─────────────────────────────┐
│             │ subscriber.dev          │ Customer.io                 │
├─────────────┼─────────────────────────┼─────────────────────────────┤
│ priced by   │ opted-in subscribers    │ profiles (people + objects) │
│ 5,000       │ $19/mo                  │ $100/mo                     │
│ 10,000      │ $39/mo                  │ $145/mo                     │
│ 25,000      │ $79/mo                  │ $280/mo                     │
│ sends       │ no limit on paid plans  │ 1M emails/mo, then add-on   │
│ free        │ 1,000 subscribers       │ trial                       │
│ AI agents   │ MCP server              │ MCP server, built-in agent  │
│ sending     │ your own provider       │ theirs, or custom SMTP      │
│ channels    │ email, webhooks         │ email, SMS, push, in-app    │
│ open source │ AGPL-3.0, self-hostable │ no                          │
└─────────────┴─────────────────────────┴─────────────────────────────┘

Customer.io details from their pricing page, checked October 2026.

## where subscriber.dev is different

› a fifth of the price

Customer.io starts at $100 a month for 5,000 profiles. The same list is $19 here, with no limit on sends.

› only people who can receive email count

Customer.io bills every profile, including objects. We count opted-in subscribers, nothing else.

› built for agents and terminals

Everything works over MCP, the API, a CLI and a TUI, so there's no dashboard to learn.

› open source

AGPL-3.0 and self-hostable with Docker Compose, so you're never locked in.

## when Customer.io is the better fit

  • You need SMS, push or in-app messages alongside email.
  • A marketing team wants a visual journey builder and drag-and-drop editor.
  • You want Customer.io's data pipelines to route events to other tools.

## switching

Import your people through the bulk API or the CLI, 500 at a time, or hand your agent a Customer.io export. Describe your campaigns and it can rebuild them as workflows, with Stripe events as triggers and exit conditions.

# from your terminal
$ npx @subscriber.dev/cli login
# from your agent
$ claude mcp add --transport http subscriber https://mcp.subscriber.dev