Tools to orchestrate, observe, and deploy LLM applications
257 companies on usedby use at least one of the 14 tools in this category with a public customer. LangSmith leads with 43 companies. Then come Braintrust (39) and Arize AI (35). 40 companies run two of these tools or more. The most common pair is LangSmith with Langchain (29 companies).Latest check Oct 7, 2026: 295 of 307 public lines checked. Counts are of companies on usedby, not of the whole market: we list a company when a public page shows its AI tools.
257
companies on usedby use a tool of this category
Companies per tool. A company using two tools counts for both.
Counts include job-post signals, drawn apart on each tool page.
Companies with a public line for each tool. Job-post signals count and are drawn apart in the proof bar.
| # | Tool | Customers | Proof |
|---|---|---|---|
| 1 |  LangSmith | 43 | |
| 2 |  Braintrust | 39 | |
| 3 |  Arize AI | 35 | |
| 4 |  Langchain | 32 | |
| 5 |  TrueFoundry | 27 | |
| 6 |  E2B | 23 | |
| 7 |  Portkey | 22 | |
| 8 |  Comet Opik | 17 | |
| 9 |  Mem0 | 16 | |
| 10 |  CrewAI | 13 | |
| 10 |  Flowise | 13 | |
| 10 |  Galileo | 13 | |
| 13 |  Fiddler AI | 10 | |
| 14 |  Contextual AI | 4 |
40 companies run two of these tools or more. The most common pair is LangSmith with Langchain, at 29 companies.
LangSmith43 customersLangSmith is used by 43 companies on usedby, 11 confirmed by a case study, a named quote or a press release. Named customers include Nvidia, Toyota, and Cisco. Who uses LangSmith, Arize AI vs LangSmith
Customer page: langchain.com. Latest check of 37 of 43 lines: Oct 6, 2026.
Braintrust39 customersBraintrust is used by 39 companies on usedby, 15 confirmed by a case study, a named quote or a press release. Named customers include Cloudflare, Coursera, and Dropbox. Who uses Braintrust, Braintrust vs LangSmith
Customer page: braintrust.dev. Latest check of 39 of 39 lines: Oct 7, 2026.
Arize AI35 customersArize AI is used by 35 companies on usedby, 9 confirmed by a case study, a named quote or a press release. Named customers include Microsoft, Booking.com, and Atlassian. Who uses Arize AI, Arize AI vs LangSmith
Customer page: arize.com. Latest check of 30 of 35 lines: Oct 5, 2026.
Langchain32 customersLangchain is used by 32 companies on usedby, 13 confirmed by a case study, a named quote or a press release. Named customers include Nvidia, Toyota, and Cisco. Who uses Langchain, Braintrust vs Langchain
Customer page: langchain.com. Latest check of 32 of 32 lines: Oct 7, 2026.
Companies first listed by a tool of this category in the last 90 days.
Side-by-side pages with the companies behind each tool.
Answers drawn from usedby data.
LangSmith, used by 43 of the 257 companies on usedby in this category. Then come Braintrust (39) and Arize AI (35). Who uses LangSmith.
LangSmith: 43 companies on usedby, against 39 for Braintrust.
Yes: 40 of the 257 companies on usedby in this category run two or more. The most common pair is LangSmith with Langchain (29 companies).
By the number of companies with a public line for each tool, read from dated captures of vendor customer pages, case studies, press releases and job posts. Job-post signals count in the totals and are shown apart. usedby lists a company when a public page shows it, so these counts describe the companies on usedby, not the whole market.