# C3 AI vs Writer: who uses which

On usedby, 35 companies use C3 AI and 74 use Writer. 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 2026-10-08: 101 of 109 public lines checked.

## Side by side

|  | [C3 AI](https://www.usedby.ai/tools/c3-ai.md) | [Writer](https://www.usedby.ai/tools/writer.md) |
|---|---|---|
| Public customers | 35 | 74 |
| Confirmed | 23 | 63 |
| Observed | 12 | 11 |
| Signals (job posts) | 0 | 0 |
| Top industries of customers | Aerospace & Defense (2), Energy, Utilities & Cleantech (2), Biotech & Pharma (1) | HealthTech & Digital Health (7), Marketing Tech (7), Fintech & Payments (5) |
| Category | Enterprise AI Platforms | Enterprise AI Platforms |
| Security | — | SOC 2 Type II, ISO 27001 ([writer.com](https://writer.com/trust/), checked 2026-10-03) |
| Your data | — | Not used to train models by default. ([writer.com](https://writer.com/trust/), checked 2026-10-03) |
| Data processing terms | — | A data processing agreement is available. ([writer.com](https://writer.com/legal/data-processing/), checked 2026-10-03) |
| Free trial | — | Free trial or free plan available. ([writer.com](https://writer.com/plans/), checked 2026-10-03) |
| Integrations | — | Snowflake, Salesforce, Contentful, Adobe Experience Manager, Asana, Atlassian, Databricks, FactSet, Gong, Google BigQuery, Google Workspace, HubSpot ([writer.com](https://writer.com/product/connectors/), checked 2026-10-03) |

## Published results

Reviewed stories only; usedby did not measure the figures.

- C3 AI: [Missile Defense Agency](https://www.usedby.ai/case-studies/missile-defense-agency-c3-ai.md): **99%**: “99% reduction in the time to generate threat data, from weeks to minutes” (captured by usedby 2026-10-08)

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Source: https://www.usedby.ai/compare/c3-ai-vs-writer · How we check: https://www.usedby.ai/methodology