Braintrust vs E2B: who uses which
Customers, public proof and the companies that use both.
On usedby, 39 companies use Braintrust and 23 use E2B. No company is listed with both yet. Braintrust leads among the DevTools & Infrastructure companies on usedby that use either tool, E2B among the Artificial Intelligence companies.Latest check Oct 7, 2026: 62 of 62 public lines checked. Counts include every proof level, job-post signals included. Companies named on both have a confirmed or observed line on each side.
Who uses Braintrust, E2B, or both
Every company with a public proof for at least one of the two tools.
39
use only Braintrust
0
companies use both
23
use only E2B
39 companies use only Braintrust, 23 use only E2B and 0 use both, out of the 62 companies on usedby that use at least one of them.
Where it lands
Newest customers
We have not started tracking changes for Braintrust yet.
Where it lands
Newest customers
We have not started tracking changes for E2B yet.
Who uses both
Companies with a confirmed or observed line on both tools.
By industry
Which tool the companies on usedby use, by industry. Shares of the companies on usedby that use Braintrust, E2B or both: a share of the companies on usedby, not of the market.
Braintrust onlyBothE2B only
More common with Braintrust
- DevTools & Infrastructure10 of the 10 DevTools & Infrastructure companies on usedby that use either tool use Braintrust.
More common with E2B
- Artificial Intelligence4 of the 6 Artificial Intelligence companies on usedby that use either tool use E2B.
Source: confirmed and observed usedby lines. Job-post signals, the weakest proof level, are left out of these shares.
Side by side
Facts from our data and from each vendor's public pages. Each line says where it comes from.
BraintrustE2BWhat customers report
Results as the vendor or the customer published them, with the source and the date.
Braintrust
Continuous signal, 30-min fix cycles
Rex
Vendor case study, braintrust.dev, captured Oct 6, 2026
E2B
we had over 50,000 users who started over 230,000 E2B sandboxes
LMArena
Vendor case study, e2b.dev, published Feb 3, 2025
from zero to $250M ARR in 12 months
Genspark
Vendor case study, e2b.dev, published May 7, 2026
Questions about Braintrust and E2B
Which is used more, Braintrust or E2B?
Braintrust has more customers on usedby: 39 against 23 for E2B. Braintrust leads among the DevTools & Infrastructure companies on usedby that use either tool, E2B among the Artificial Intelligence companies.
Do companies use both Braintrust and E2B?
usedby has not found a company with a confirmed or observed line on both Braintrust and E2B yet.
Who uses Braintrust?
39 companies on usedby, each with the public page that shows it. See who uses Braintrust.
Who uses E2B?
23 companies on usedby, each with the public page that shows it. See who uses E2B.
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 three proof levels: confirmed, observed or signal (a job post, the weakest). A company is named as using both tools when its lines on both are confirmed or observed.