Braintrust vs LangSmith: who uses which
Customers, public proof and the companies that use both.
On usedby, 39 companies use Braintrust and 43 use LangSmith. No company is listed with both yet. Braintrust leads among the DevTools & Infrastructure companies on usedby that use either tool, LangSmith among the HR & Recruiting companies.Latest check Oct 7, 2026: 76 of 82 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, LangSmith, or both
Every company with a public proof for at least one of the two tools.
39
use only Braintrust
0
companies use both
43
use only LangSmith
39 companies use only Braintrust, 43 use only LangSmith and 0 use both, out of the 82 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
No new customer since tracking started on October 3, 2026.
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, LangSmith or both: a share of the companies on usedby, not of the market.
Braintrust onlyBothLangSmith only
More common with Braintrust
- DevTools & Infrastructure10 of the 12 DevTools & Infrastructure companies on usedby that use either tool use Braintrust.
More common with LangSmith
- HR & Recruiting5 of the 6 HR & Recruiting companies on usedby that use either tool use LangSmith.
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.
BraintrustLangSmithWhat 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
LangSmith
No reviewed story for LangSmith yet.
Questions about Braintrust and LangSmith
Which is used more, Braintrust or LangSmith?
LangSmith has more customers on usedby: 43 against 39 for Braintrust. Braintrust leads among the DevTools & Infrastructure companies on usedby that use either tool, LangSmith among the HR & Recruiting companies.
Do companies use both Braintrust and LangSmith?
usedby has not found a company with a confirmed or observed line on both Braintrust and LangSmith yet.
Who uses Braintrust?
39 companies on usedby, each with the public page that shows it. See who uses Braintrust.
Who uses LangSmith?
43 companies on usedby, each with the public page that shows it. See who uses LangSmith.
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.