# Fiddler AI vs LangSmith: who uses which

On usedby, 10 companies use Fiddler AI and 43 use LangSmith. No company is listed with both yet. Counts include every proof level, job-post signals included. Companies named on both have a confirmed or observed line on each side. Latest check 2026-10-06: 47 of 53 public lines checked.

## Side by side

|  | [Fiddler AI](https://www.usedby.ai/tools/fiddler-ai.md) | [LangSmith](https://www.usedby.ai/tools/langsmith.md) |
|---|---|---|
| Public customers | 10 | 43 |
| Confirmed | 1 | 11 |
| Observed | 9 | 31 |
| Signals (job posts) | 0 | 1 |
| Top industries of customers | Fintech & Payments (2), Government & GovTech (1), Insurance & InsurTech (1) | HR & Recruiting (5), Fintech & Payments (4), Biotech & Pharma (2) |
| Category | LLM Ops & Frameworks | LLM Ops & Frameworks |
| Data processing terms | A data processing agreement is available. ([fiddler.ai](https://www.fiddler.ai/legal/dpa), checked 2026-10-08) | — |
| Free trial | Free trial or free plan available. ([fiddler.ai](https://www.fiddler.ai/pricing), checked 2026-10-08) | Free trial or free plan available. ([langchain.com](https://www.langchain.com/pricing), checked 2026-10-04) |
| Pricing | — | Developer: $0 seat per month; Plus: $39 seat per month; Enterprise: contact sales ([langchain.com](https://www.langchain.com/pricing), checked 2026-10-04) |

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Source: https://www.usedby.ai/compare/fiddler-ai-vs-langsmith · How we check: https://www.usedby.ai/methodology