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Customer.io vs Substack
Customer.io: Data-driven personalized customer journeys. Substack: Writers making money doing the work they believe in. Same fact set for both, straight from each vendor's docs.
Customer.io
- Free tier
- No free plan; 14-day trial
- Paid from
- $100/mo · pricing page
- Public API
- Yes docs
- MCP server
- Yes · Official remote MCP server exposing Journeys and Data Pipelines APIs (docs.customer.io/ai/mcp).
- Best for
- Data-driven personalized customer journeys
- Website
- https://customer.io
Substack
- Free tier
- Free to publish, no subscriber cap
- Paid from
- No monthly fee; 10% of paid subscription revenue plus Stripe fees · pricing page
- Public API
- Yes docs
- MCP server
- Community · Community servers on GitHub only
- Best for
- Writers making money doing the work they believe in
- Website
- https://substack.com
Which one?
Customer.io suits data-driven personalized customer journeys. Substack suits writers making money doing the work they believe in. Pricing changes; the fact tables above link both vendors' live pricing pages. For the rest of the field, see Customer.io alternatives, Substack alternatives, or the full table.