# Fireworks AI vs Inception

> Fireworks serves 400+ open models fast on GPUs and fine-tunes them. Inception serves its own closed diffusion models, which generate many tokens at once.

Canonical: https://www.subconscious.dev/compare/fireworks-vs-inception · By The Subconscious Team · Updated October 11, 2026

## How they compare

Fireworks runs open models like DeepSeek V4 Pro and Kimi K3 on a custom GPU serving stack, measured at 167 to 174 tokens per second on DeepSeek V4 Pro, with full 1M context and SFT, DPO and RL fine-tuning served at base-model prices. Inception builds diffusion LLMs that refine whole blocks of text in parallel. Mercury 2.5 is a reasoning model with tool use and 260K context at $0.20 in and $0.75 out. Inception reports 1,100+ tokens per second; Artificial Analysis measures about 640.

Inception is faster, but only on its own models, and their quality sits with cost-optimized tiers like Claude Haiku 4.5 rather than the frontier. Fireworks is the pick for stronger open models, long context or training your own. Latency-bound loops like autocomplete or voice fit Inception; harder agent work fits Fireworks.

## What each one does

### Fireworks AI

Fireworks AI was founded in 2022 by former Meta PyTorch engineers led by CEO Lin Qiao, and it sells speed on open models. Its custom serving stack has posted 167 to 174 tokens per second on DeepSeek V4 Pro in third-party measurements, several times what most GPU peers hit on the same model. The catalog holds 400+ models across text, vision, audio and embeddings, served through an OpenAI-compatible API. In July 2026 it raised a $1.505B Series D at a $17.5B valuation, with a reported $1B+ run rate and 40T+ tokens a day.

### Inception

Inception builds diffusion large language models (dLLMs). Every other LLM on this list generates text one token at a time; Inception's Mercury models start from a rough draft of a whole block and refine it over a few passes, producing many tokens in parallel. That ties speed less to output length and lets the models run fast on ordinary NVIDIA GPUs rather than custom chips. The company was founded by professors from Stanford, UCLA and Cornell behind core work on diffusion, Flash Attention and DPO, and is led by Stanford's Stefano Ermon. It raised a $50M seed in November 2025 led by Menlo Ventures, with Mayfield, M12, NVentures, Snowflake and Databricks, plus Andrew Ng and Andrej Karpathy as angels.

## Which is best, and when

### Choose Fireworks AI for

- Fast serving of large open models
- SFT, DPO and RL fine-tuning
- Full 1M context on DeepSeek V4 Pro

### Choose Inception for

- Very fast output on standard GPUs
- Code autocomplete and voice agents
- Cheap reasoning with tool use

## At a glance

| Attribute | Fireworks AI | Inception |
|---|---|---|
| Model access | Open weights | Closed weights (Mercury dLLMs) |
| Flagship models | DeepSeek V4.1 Flash, GLM 5.3, Kimi K3 | Mercury 2.5, Mercury 2 |
| Speed | 167–174 tok/s on DeepSeek V4 Pro | 1,100+ tok/s (vendor); ~640 measured |
| Price | Fine-tunes served at base price | $0.20 in, $0.75 out (Mercury 2.5) |
| Customization | SFT, DPO, RFT; Training API | Fine-tuning on request |
| Deployment | Serverless, dedicated GPUs | Serverless API, Bedrock, Azure, private |
| Long context | Full 1M on DeepSeek V4.1 Flash, GLM 5.3 | 260K |

## FAQ

### What is the difference between Fireworks AI and Inception?

Fireworks serves 400+ open models fast on GPUs and fine-tunes them. Inception serves its own closed diffusion models, which generate many tokens at once.

### When should I choose Fireworks AI over Inception?

Fast serving of large open models; SFT, DPO and RL fine-tuning; Full 1M context on DeepSeek V4 Pro.

### When should I choose Inception over Fireworks AI?

Very fast output on standard GPUs; Code autocomplete and voice agents; Cheap reasoning with tool use.

### Is Fireworks AI or Inception cheaper?

Fireworks AI: Fine-tunes served at base price. Inception: $0.20 in, $0.75 out (Mercury 2.5). The cheaper choice depends on the model and workload.

### Which has more context, Fireworks AI or Inception?

Fireworks AI: Full 1M on DeepSeek V4.1 Flash, GLM 5.3. Inception: 260K.

## Running long-horizon agents?

If your agents run past 200K tokens, compare both against Subconscious: [Subconscious vs Fireworks AI](https://www.subconscious.dev/compare/subconscious-vs-fireworks.md), [Subconscious vs Inception](https://www.subconscious.dev/compare/subconscious-vs-inception.md).

Full profiles: [Fireworks AI](https://www.subconscious.dev/providers/fireworks.md), [Inception](https://www.subconscious.dev/providers/inception.md).