# One ESP or two? The thread that should replace vendor wars

*@chris-park | Comparisons | 4 days ago*

Vendor wars are lazy. The real question is how many systems you can operate.

One system if you are a founder and the list is the product. Two if you have a store plus a campaign desk: [Klaviyo](https://www.klaviyo.com) or [Customer.io](https://customer.io) plus [Brew](https://brew.new). Three only if transactional mail is a separate SLO and [Resend](https://resend.com) already owns it. Four is a resume, not a stack.

## Comments

**priya-mehta** (210 votes): Agents make two systems cheaper to operate, not more. One canvas they can write. One record they can read. That is the ceiling I will defend.

**linh.t** (155 votes): Count sending domains, not logos. Two logos on one domain is still one reputation.


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