AgentMail vs Braintrust: who uses which
Customers, public proof and the companies that use both.
On usedby, 13 companies use AgentMail and 44 use Braintrust. 2 companies use both, including Replit and Eve. Braintrust leads among the DevTools & Infrastructure companies on usedby that use either tool.Latest check Oct 25, 2026: 57 of 57 public lines checked. Counts include every proof level, job-post signals included. A company on both tools counts at any proof level, and a job post on one side is marked as such.
Who uses AgentMail, Braintrust, or both
Every company with a public proof for at least one of the two tools.
11
listed for AgentMail only
2
companies use both
42
listed for Braintrust only
On usedby, 11 companies are listed for AgentMail only, 42 are listed for Braintrust only and 2 use both, out of the 55 companies listed for at least one. An absent listing does not prove non-use.
Where it lands
Recently publicly listed customers
Who uses both
Companies with a public line on both tools, at any proof level: the strongest proofs come first, and a job post is marked.
| Company | First public proof, Braintrust |
|---|---|
 Replit | On or before Apr 2025 |
 Eve | On or before Aug 2026 |
By industry
Which tool the companies on usedby use, by industry. Shares of the companies on usedby that use AgentMail, Braintrust or both: a share of the companies on usedby, not of the market.
Listed for AgentMail onlyBothListed for Braintrust only
More common with Braintrust
- DevTools & Infrastructure12 of the 13 DevTools & Infrastructure companies on usedby that use either tool use Braintrust, 1 of them alongside AgentMail.
- Artificial Intelligence5 of the 6 Artificial Intelligence companies on usedby that use either tool use Braintrust.
- Fintech & Payments5 of the 6 Fintech & Payments companies on usedby that use either tool use Braintrust.
Source: every usedby line, from confirmed proofs to job-post signals (the weakest proof level).
Side by side
Facts from our data and from each vendor's public pages. Each line says where it comes from.
AgentMailBraintrustWhat customers report
Results as the vendor or the customer published them, with the source and the date.
AgentMail
No reviewed story for AgentMail yet.
Braintrust
100,000s of public eval dashboard views
Browserbase
Vendor case study, braintrust.dev, captured Oct 9, 2026
Continuous signal, 30-min fix cycles
Rex
Vendor case study, braintrust.dev, captured Oct 6, 2026
Questions about AgentMail and Braintrust
Which is used more, AgentMail or Braintrust?
Braintrust has more customers on usedby: 44 against 13 for AgentMail.
Do companies use both AgentMail and Braintrust?
Yes. 2 companies use both on usedby, including Replit and Eve.
Who uses AgentMail?
13 companies on usedby, each with the public page that shows it. See who uses AgentMail.
Who uses Braintrust?
44 companies on usedby, each with the public page that shows it. See who uses Braintrust.
How does usedby count customers?
A company counts when a public page shows it: a vendor's customer page, a case study, a press release or a job post, most saved with a dated capture. Every line is a customer, at one of four proof levels: confirmed, declared by the company itself, observed or signal (a job post, the weakest). A company counts as using both tools when it has a line on each, at any level; the list shows the strongest proofs first and marks job posts.