# How Cursor uses Fireworks AI

**6–10x**: “6–10x lower inference cost vs comparable frontier coding models”

As published on [fireworks.ai](https://fireworks.ai/customers/cursor-composer-2-reinforcement-learning), June 2026. Captured by usedby on 2026-10-31.

- Company: [Cursor](https://www.usedby.ai/companies/cursor.md)
- Tool: [Fireworks AI](https://www.usedby.ai/tools/fireworks-ai.md)
- Industry: [DevTools & Infrastructure](https://www.usedby.ai/companies/industry/devtools-infrastructure.md)

## The use case: how Cursor deploys Fireworks AI

Cursor uses Fireworks AI as the inference and rollout layer for reinforcement learning of its Composer 2 coding model, running RL across several distributed global clusters without building its own dedicated inference stack.

Summary written by usedby from the source page, in English. The figures are those of Fireworks AI and Cursor, not ours.

> Fireworks provides the inference and rollout layer that allows Cursor to scale RL without building a dedicated inference system.

- **3–4**: “Distributed reinforcement learning across 3–4 global clusters”
- **98%**: “Cross-region model updates with ~98%+ optimization in transfer size”

> We have finite engineers like everybody else. We would prefer to have engineers make training more efficient and more precise rather than spin up an inference effort.
>
> Federico Cassano, Research Lead, Cursor

Source: [fireworks.ai](https://fireworks.ai/customers/cursor-composer-2-reinforcement-learning), captured 2026-10-31.

> ...because it's way more performant than the open source engines and is what we use in production. our rl inference scales elastically and globally because of it. when we have low prod traffic we scale up RL, when we have high prod traffic, we scale down RL.
>
> Federico Cassano, AI Researcher

Source: [fireworks.ai](https://fireworks.ai/), captured 2026-10-05.

> Fireworks has been a key partner in helping us train and serve the models behind Cursor at scale. Their platform supports the high-throughput RL workloads and production inference required for Composer, giving us the speed, reliability, and efficiency to keep pushing the frontier of AI coding.
>
> Sualeh Asif, CPO

Source: [fireworks.ai](https://fireworks.ai/), captured 2026-10-05.

> We work with Fireworks to push on inference.
>
> Federico Cassano, Research Lead

Source: [fireworks.ai](https://fireworks.ai/customers), captured 2026-10-31.

## Other AI tools used by Cursor

- [Claude](https://www.usedby.ai/tools/claude.md) — Confirmed
- [Notion](https://www.usedby.ai/tools/notion.md) — Confirmed
- [Together AI](https://www.usedby.ai/tools/together-ai.md) — Confirmed
- [Baseten](https://www.usedby.ai/tools/baseten.md) — Observed
- [Clay](https://www.usedby.ai/tools/clay.md) — Observed
- [Dust](https://www.usedby.ai/tools/dust.md) — Observed

## Fireworks AI users in DevTools & Infrastructure

- [Vercel](https://www.usedby.ai/companies/vercel.md) — Confirmed
- [Hasura](https://www.usedby.ai/companies/hasura.md) — Declared by the company
- [Linear](https://www.usedby.ai/companies/linear.md) — Declared by the company
- [Replit](https://www.usedby.ai/companies/replit.md) — Declared by the company
- [Turbopuffer](https://www.usedby.ai/companies/turbopuffer.md) — Declared by the company
- [Cognition](https://www.usedby.ai/companies/cognition.md) — Observed

## What usedby checked

We compared the story with its live page on 2026-10-31.

- Checked: the figure 6–10x is printed word for word on the page, near the name of Cursor.
- Checked: the passage quoted above is copied word for word from the page, near the name of Cursor.
- Checked: each number in our summary is printed on the page.
- Checked: the publication date is read from the page’s own metadata, never guessed.
- Checked: Cursor uses Fireworks AI. Confirmed line. Latest check across sources: 2026-10-31.
- Not checked: the result itself. We quote it; we did not measure it.

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Source: https://www.usedby.ai/case-studies/cursor-fireworks-ai · How we check: https://www.usedby.ai/methodology