Because of the limits of the free versions of Cursor and Kiro, the author purchased access to the official DeepSeek API, personally testing the V4-Flash and Pro models and documenting the pitfalls encountered throughout the process, from adding credit and configuring the tools to writing code and debugging in real projects.
| Model | Input price (per million tokens) | Output price (per million tokens) | Core strengths |
|---|---|---|---|
| DeepSeek-V4-Flash | CNY 1 | CNY 3 | Fast inference and low cost; suitable for everyday development and batch generation |
| DeepSeek-V4-Pro | CNY 2 | CNY 6 | Stronger reasoning; suitable for complex architectures, algorithm problems, and deep debugging |
The author added CNY 30. With usage equivalent to writing 20,000 lines of code per day and frequent conversational debugging, the Flash version still had credit left after nearly two days. Its cost was roughly 10%–20% that of closed-source models.
Fast: It generates a 1,000-line Python script in seconds, more than twice as fast as GPT-3.5, with coherent output and no stalling.
Strong coding ability: It supports 300+ programming languages, can directly achieve AC on medium-difficulty LeetCode problems, and can refactor 1,000 lines of legacy project code.
Long context: With a 1M context window, you can provide an entire codebase for cross-file dependency analysis and hidden-bug detection.
Drawback: It occasionally makes logical mistakes in highly complex architectural designs and extremely difficult algorithm problems.
When writing microservice architectures and database schemas, it can draw complete ER diagrams and API documentation while identifying performance bottlenecks in advance.
Stronger debugging: For a cross-origin bug that had gone unresolved for three hours, it gave three solutions and marked the relevant CORS details.
Broad scenario coverage: technical documentation, project proposals, and copy editing.
Drawback: It is slower than Flash and costs more, so it is better suited to complex scenarios.
Create an API Key on the DeepSeek Open Platform (platform.deepseek.com).
In Cursor, go to Settings → Models, enable OpenAI API Key, and enter https://api.deepseek.com/v1 under Override OpenAI Base URL (the /v1 suffix is required; otherwise, the request returns 404).
Add the deepseek-v4-flash model (or deepseek-v4-pro).
When the free version of Cursor displays “Named models unavailable,” enter “Please use the deepseek-v4-flash model to answer the following question: ...” in the conversation to force it to use the model.
For Kiro, go to Settings → Providers → Add Custom Provider → OpenAI Compatible, then enter the Base URL and API Key.
Use Flash for everyday development and batch tasks; use Pro for complex architectures, algorithm problems, and deep debugging. Official top-ups support WeChat Pay and Alipay, and the process is smooth.
DeepSeek V4 Flash
