comparison
A European alternative to the OpenAI API
OpenAI sells the best-known proprietary models through an API that most of the industry has copied. GPU Flow speaks that same API but serves open-source models (Qwen, GLM, Gemma, Nemotron, ALIA, Whisper). You keep your code and your SDK; what changes is which model you use, what happens to your data, what you pay and in which currency. This page is honest about the trade: for many workloads an open 27B model is enough and cheaper; for some, GPT-5 class models are still the right tool.
The short version
| OpenAI | GPU Flow | |
|---|---|---|
| Models | Proprietary: GPT-5, GPT-5.4 and GPT-5.5 families, plus audio models such as Whisper | Open source: 13 models, including Qwen3.8 27B, GLM 5.3, Gemma 4, Nemotron, ALIA 40B, Whisper and Qwen3-TTS |
| Training on API data | Not since March 2023, unless you opt in to share data, per its documentation | Never, on any plan |
| Prices and invoice | In USD | EUR with Spanish VAT; reverse charge for EU businesses with a VAT number |
| SDK | OpenAI SDK | The same OpenAI SDK, plus the Anthropic SDK |
Price per million tokens: GPT-5 family vs open models on GPU Flow
Blended cost for a typical production workload of 100 million input and 20 million output tokens a month. Each provider in its own currency: OpenAI in USD, GPU Flow in EUR.
| Model | Input | Output | 100M in + 20M out / month |
|---|---|---|---|
| GPU Flow Qwen3.8 27B | €0.10 | €0.30 | €16.00 |
| GPU Flow GLM 5.3 NVFP4 | €1.206 | €3.789 | €196.38 |
| OpenAI gpt-5-nano | $0.05 | $0.40 | $13.00 |
| OpenAI gpt-5.4-nano | $0.20 | $1.25 | $45.00 |
| OpenAI gpt-5-mini | $0.25 | $2.00 | $65.00 |
| OpenAI gpt-5.4-mini | $0.75 | $4.50 | $165.00 |
| OpenAI gpt-5 | $1.25 | $10.00 | $325.00 |
| OpenAI gpt-5.4 | $2.50 | $15.00 | $550.00 |
| OpenAI gpt-5.5 | $5.00 | $30.00 | $1,100.00 |
OpenAI prices checked on 9 November 2026 on its official pricing page: standard tier, in USD and not converted; gpt-5.4 and gpt-5.5 at the under-272K context rate. GPU Flow prices in EUR and live. Source: developers.openai.com/api/docs/pricing
Two honest notes. First, OpenAI’s nano tier is very cheap per token; if it is good enough for your task, it can win on price. Second, price per token is not quality per token: GPT-5 and GPT-5.5 outperform open models on the hardest tasks. In the product work where an open model does the job comfortably (support, extraction, summarisation, coding assistance, classification), the price difference is the one you see in the table.
Audio: Whisper on GPU Flow vs OpenAI
Whisper is OpenAI’s own open-source model. On OpenAI’s API it costs $0.006 per minute; gpt-4o-mini-transcribe about $0.003 per minute, by OpenAI’s own estimate. On GPU Flow, Whisper large-v3 costs €0.0015 per minute, on the same /v1/audio/transcriptions call.
Migrating is three lines
python
client = OpenAI(
base_url="https://api.gpuflow.ai/v1", # was api.openai.com
api_key=os.environ["GPUFLOW_API_KEY"],
)
r = client.chat.completions.create(model="qwen-3.8-27b", messages=messages) # was gpt-5-miniStreaming, function calling, JSON mode and reasoning keep working on the models that support them; each model page says which. The full guide covers the account, model mapping, streaming and tools.
When to stay on OpenAI
- 1Your task needs frontier reasoning and your evals show open models falling short.
- 2You depend on OpenAI-only features (specific assistants, fine-tuned GPT models, image generation).
- 3The invoice currency does not matter to you and the nano tier is enough.
When to move to GPU Flow
- 1Your DPO, your customers or your sector ask for a European data processor, with a DPA, GDPR, ISO 27001 and ENS Medium.
- 2You want to pay less per token on mid-size tasks without rewriting code.
- 3You want open weights you can audit, self-host later or run on a dedicated GPU.
- 4You invoice in euros and want VAT handled properly.
- 5You need Spanish and co-official languages (ALIA 40B).
Frequently asked questions
Is GPU Flow compatible with the OpenAI SDK?
Yes. Change the base URL and the key; the rest of your code stays.
Are open-source models as good as GPT-5?
For many product tasks, a 27B model like Qwen3.8 does the job comfortably; for the hardest reasoning, GPT-5 class models are still ahead. Test with your own data: the €5 welcome credit is for that.
Is GPU Flow cheaper than OpenAI?
It depends on the model and the tier you compare against. The table above puts both side by side, with OpenAI’s prices in USD as it publishes them. On the nano tier, OpenAI’s price per token is very low.
Can I run both during migration?
Yes. Two clients, same code, route by task.
Test it on your own prompts with €5 free
Create your account, change the base URL and run your prompts against any model in the catalogue.