# OpenAI vs Fireworks AI

Canonical: https://inetgeek.com/compare/openai-vs-fireworks/

Every value below is read from OpenAI's and Fireworks AI's own documentation. See https://inetgeek.com/methodology/ for how.

## At a glance

| Criterion | OpenAI | Fireworks AI |
| --- | --- | --- |
| Pricing model | Per million tokens, with a second rate above the short-context threshold — long-context input and output cost roughly double. Batch, Flex, Fast and standard tiers are priced separately, and regional processing adds a 10% uplift on models released from March 2026. | Three products on one bill. Serverless inference is per token, per model. Fine-tuning is per million TRAINING tokens by parameter band — $0.50 for models up to 16B, $10.00 above 300B. Dedicated GPUs are hourly: $7.00 for an H100 or H200, $10.00 for a B200. |
| Input price, top model | $10 per million input tokens for gpt-6-astra at short context, rising to $20 above the short-context threshold. gpt-5.6-sol is $4 and gpt-5.6-terra $2. | $3.00 per million input tokens for Kimi K3, the most expensive model in its serverless catalogue. Fireworks hosts other labs' open-weight models rather than its own, so "flagship" here means the top of what it serves. |
| Output price, top model | $50 per million output tokens for gpt-6-astra at short context, $75 at long context. | $15.00 per million output tokens for Kimi K3. |
| Input price, cheapest model | $0.20 per million input tokens for gpt-5.6-luna at short context, with output at $1.20. | $0.15 per million input tokens for GLM 5.3 Flash, with output at $0.50. DeepSeek-V4-Flash is $0.22 in and $0.66 out — the same model DeepSeek itself sells at $0.44 peak. |
| Context window | 1,050,000 tokens on gpt-6-astra, of which at most 922,000 may be input. | 1,048,576 tokens on Kimi K3, GLM 5.3 and both DeepSeek V4 variants; 262,144 on Qwen3.8 and 131,072 on Muse Glimmer 30B. The window is the model's, not Fireworks'. |
| Max output tokens | 128,000 tokens on gpt-6-astra. | No separate output cap. max_tokens is bounded by the model's context length — prompt plus completion must fit inside it — and what happens on overflow is set by context_length_exceeded_behavior rather than a fixed ceiling. |
| Prompt caching | Supported | Supported |

## Where they differ

### Pricing model

- OpenAI: Per million tokens, with a second rate above the short-context threshold — long-context input and output cost roughly double. Batch, Flex, Fast and standard tiers are priced separately, and regional processing adds a 10% uplift on models released from March 2026. ([source](https://platform.openai.com/docs/pricing))
- Fireworks AI: Three products on one bill. Serverless inference is per token, per model. Fine-tuning is per million TRAINING tokens by parameter band — $0.50 for models up to 16B, $10.00 above 300B. Dedicated GPUs are hourly: $7.00 for an H100 or H200, $10.00 for a B200. ([source](https://fireworks.ai/pricing))

### Input price, top model

- OpenAI: $10 per million input tokens for gpt-6-astra at short context, rising to $20 above the short-context threshold. gpt-5.6-sol is $4 and gpt-5.6-terra $2. ([source](https://platform.openai.com/docs/pricing))
- Fireworks AI: $3.00 per million input tokens for Kimi K3, the most expensive model in its serverless catalogue. Fireworks hosts other labs' open-weight models rather than its own, so "flagship" here means the top of what it serves. ([source](https://fireworks.ai/models))

### Output price, top model

- OpenAI: $50 per million output tokens for gpt-6-astra at short context, $75 at long context. ([source](https://platform.openai.com/docs/pricing))
- Fireworks AI: $15.00 per million output tokens for Kimi K3. ([source](https://fireworks.ai/models))

### Input price, cheapest model

- OpenAI: $0.20 per million input tokens for gpt-5.6-luna at short context, with output at $1.20. ([source](https://platform.openai.com/docs/pricing))
- Fireworks AI: $0.15 per million input tokens for GLM 5.3 Flash, with output at $0.50. DeepSeek-V4-Flash is $0.22 in and $0.66 out — the same model DeepSeek itself sells at $0.44 peak. ([source](https://fireworks.ai/models))

### Context window

- OpenAI: 1,050,000 tokens on gpt-6-astra, of which at most 922,000 may be input. ([source](https://platform.openai.com/docs/models/gpt-6-astra))
- Fireworks AI: 1,048,576 tokens on Kimi K3, GLM 5.3 and both DeepSeek V4 variants; 262,144 on Qwen3.8 and 131,072 on Muse Glimmer 30B. The window is the model's, not Fireworks'. ([source](https://fireworks.ai/models))

### Max output tokens

- OpenAI: 128,000 tokens on gpt-6-astra. ([source](https://platform.openai.com/docs/models/gpt-6-astra))
- Fireworks AI: No separate output cap. max_tokens is bounded by the model's context length — prompt plus completion must fit inside it — and what happens on overflow is set by context_length_exceeded_behavior rather than a fixed ceiling. ([source](https://fireworks.ai/docs/api-reference/post-chatcompletions))

## Which should you choose?

Pick OpenAI if Work that fits inside the short-context rate, where the cheapest tier is $0.20 per million input tokens and the batch tier halves everything above it.

Pick Fireworks AI if Running open-weight models without operating GPUs — the same DeepSeek and Qwen checkpoints the labs publish, served per token, with a path to dedicated hardware if throughput demands it.

Consider something else: OpenAI — Long prompts cross into the long-context rate and roughly double the bill, which is a cliff the flat-rate vendors do not have.

Consider something else: Fireworks AI — You want a frontier proprietary model: Fireworks serves other people's open weights, so the ceiling is whatever the open ecosystem has released.

## Documented by only one

- Free tier: Fireworks AI: Yes
- Batch discount: OpenAI: 50% off input and output through the Batch API: gpt-6-astra falls from $10/$50 to $5/$25 at short context.
- H100 SXM, per GPU-hour: Fireworks AI: $7.00 per hour for an H100 80GB on demand, or $8.00 on the shorter commitment shown beside it. The same rate applies to an H200 141GB.
- Largest GPU offered: Fireworks AI: 180GB per GPU on a B200, at $10.00 an hour on demand.

## Questions this comparison answers

**Should I choose OpenAI or Fireworks AI?**

Pick OpenAI if Work that fits inside the short-context rate, where the cheapest tier is $0.20 per million input tokens and the batch tier halves everything above it.
Pick Fireworks AI if Running open-weight models without operating GPUs — the same DeepSeek and Qwen checkpoints the labs publish, served per token, with a path to dedicated hardware if throughput demands it.