Comparison · DeepSeek and OpenAI
DeepSeek V4.1 Flash 1017 vs GPT-5.4 Nano
Listed API prices of DeepSeek V4.1 Flash 1017 and GPT-5.4 Nano turned into the cost of the same three standard tasks and what each provider’s API documentation says about features that break on a switch. Output quality, speed and answer length are not compared.
Calculated impact cost per task and per month
For an L2 task (deep analysis over a 50,000-token document, 3 steps), DeepSeek V4.1 Flash 1017 costs $0.051 and GPT-5.4 Nano $0.036 at the prices listed in the United States on , so DeepSeek V4.1 Flash 1017 is 44.3 % more than GPT-5.4 Nano, counting visible output only, without cache discounts or hidden reasoning.
| Task | DeepSeek V4.1 Flash 1017, per task | GPT-5.4 Nano, per task | DeepSeek V4.1 Flash 1017, per month | GPT-5.4 Nano, per month | DeepSeek V4.1 Flash 1017 vs GPT-5.4 Nano, per task |
|---|---|---|---|---|---|
| L1Micro-task (classification or strict JSON extraction) | $0.0007per L1 task | $0.0006per L1 task | $10.07per month | $8.03per month | +25.5 % |
| L2Deep analysis over a 50,000-token document | $0.051per L2 task | $0.036per L2 task | $748.98per month | $519.03per month | +44.3 % |
| L3Agentic coding loop, 15 steps | $0.405per L3 task | $0.274per L3 task | $5,919.57per month | $4,005.51per month | +47.8 % |
Calculated Per month: 20 tasks an hour around the clock, 730 hours.
Prices USD per 1M tokens
| Price | DeepSeek V4.1 Flash 1017 | GPT-5.4 Nano |
|---|---|---|
| Input, per 1M tokens | $0.300 | $0.200 |
| Output, per 1M tokens | $1.20 | $1.25 |
| Price from | Provider's price list · source page Published | OpenRouter · source page (data) Published |
| Read | · the United States | · the United States |
| Context window | 1,048,576 tokens | 400,000 tokens |
What can I use it for? six common tasks, our data checks
Quality on your task: not measured by Measured Lab yet.
| Task | DeepSeek V4.1 Flash 1017 | GPT-5.4 Nano |
|---|---|---|
| Answer customer messages | Fits on price and context | — |
| Pull data from invoices and documents with strict JSON and page images | Not confirmed: a strict JSON schema request was refused in our test call on 17 Oct 2026 | — |
| Summarize documents and meetings | Fits on price and context | — |
| Translate content | Fits on price and context | — |
| Chat assistant on your website | Fits on price and context | — |
| Write and review code with tool calls | Fits on price and context | — |
| Tasks it fits | 5 of 6 | — |
Checks of our data for six common tasks: a published price, a context window and answer length for the task and, where the task needs them, strict JSON output, page images and tool calls; prices, cost a month and terms for each model on its model card. GPT-5.4 Nano is not in the model picker. Compare models for your own task in the model picker.
What breaks when you switch Published provider documentation
Moving from DeepSeek to OpenAI: every feature that DeepSeek’s documentation lists as supported is also listed as supported by OpenAI.
Moving from OpenAI to DeepSeek, 4 of the 5 features may not carry over, by each provider’s documentation:
- Strict JSON schemas — OpenAI: yes; DeepSeek: partly. Code that parses answers without checks starts failing where a provider promises only valid JSON, not your schema.
- Parallel tool calls — OpenAI: yes; DeepSeek: not stated. An agent built around several calls per turn gets one call per turn: more round trips, more input tokens, slower runs.
- Streamed tool arguments — OpenAI: yes; DeepSeek: not stated. An interface that shows arguments as they are written sees nothing until the whole call is ready.
- Cache covers tool definitions — OpenAI: yes; DeepSeek: not stated. Where the cache does not cover tool definitions, a long tool list is paid as fresh input on every request.
| Feature of the API | DeepSeek | OpenAI |
|---|---|---|
| Strict JSON schemas | Partly | Yes |
| Parallel tool calls | Not stated | Yes |
| Streamed tool arguments | Not stated | Yes |
| Reasoning with tools | Yes | Yes |
| Cache covers tool definitions | Not stated | Yes |
What each provider’s own API documentation says, read ; “not stated” is not the same as “no”. Quotes and sources: what breaks when you switch AI APIs.
Price changes in the last 30 days
- The listed price of DeepSeek V4.1 Flash 1017 changed on on OpenRouter: input $0.30 → $0.0060, output $1.20 → $0.50 per 1M tokens. Briefing