Comparison · DeepSeek and OpenAI
DeepSeek V4 Flash Vision Exp vs GPT-5.4 Mini
Listed API prices of DeepSeek V4 Flash Vision Exp and GPT-5.4 Mini 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 Flash Vision Exp costs $0.074 and GPT-5.4 Mini $0.133 at the prices listed in the United States on , so DeepSeek V4 Flash Vision Exp is 44.3 % less than GPT-5.4 Mini, counting visible output only, without cache discounts or hidden reasoning.
| Task | DeepSeek V4 Flash Vision Exp, per task | GPT-5.4 Mini, per task | DeepSeek V4 Flash Vision Exp, per month | GPT-5.4 Mini, per month | DeepSeek V4 Flash Vision Exp vs GPT-5.4 Mini, per task |
|---|---|---|---|---|---|
| L1Micro-task (classification or strict JSON extraction) | $0.0009per L1 task | $0.0020per L1 task | $13.49per month | $29.57per month | −54.4 % |
| L2Deep analysis over a 50,000-token document | $0.074per L2 task | $0.133per L2 task | $1,079.23per month | $1,938.15per month | −44.3 % |
| L3Agentic coding loop, 15 steps | $0.591per L3 task | $1.03per L3 task | $8,624.22per month | $14,996.02per month | −42.5 % |
Calculated Per month: 20 tasks an hour around the clock, 730 hours.
Prices USD per 1M tokens
| Price | DeepSeek V4 Flash Vision Exp | GPT-5.4 Mini |
|---|---|---|
| Input, per 1M tokens | $0.440 | $0.750 |
| Output, per 1M tokens | $1.32 | $4.50 |
| Price from | OpenRouter · source page (data) Published | Provider's price list · source page 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 Flash Vision Exp | GPT-5.4 Mini |
|---|---|---|
| Answer customer messages | — | Fits on price and context |
| Pull data from invoices and documents with strict JSON and page images | — | Fits on price and context |
| 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 | — | 6 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. DeepSeek V4 Flash Vision Exp 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 Flash Vision Exp changed on on OpenRouter: input $0.22 → $0.44, output $0.65 → $1.32 per 1M tokens. Briefing