DeepSeek.

DeepSeek is a free AI chatbot and family of open-weight language models from the Chinese AI lab DeepSeek, built for anyone who wants frontier-class chat, reasoning and coding help without a subscription. The chat app at DeepSeek’s official website, deepseek.com, is free to use, and the developer API is pay-as-you-go from $0.15 per million input tokens. DeepSeek is the budget benchmark every other chatbot now gets compared against.

What is DeepSeek?

DeepSeek is an AI assistant you can talk to in a browser or mobile app, backed by the company’s own large language models. Ask it questions, draft and rewrite text, summarise documents, write and debug code, or work through maths and logic problems step by step. Its thinking mode shows the model’s chain of reasoning before the final answer, which makes its problem-solving unusually transparent for a free tool.

Two things made DeepSeek famous. First, its models are released as open weights, so developers can download and run them on their own hardware instead of depending on a hosted service. Second, its API pricing undercuts Western rivals by a wide margin — according to DeepSeek’s official API documentation, the current DeepSeek-V4.1-Flash model charges $0.15 per million input tokens off-peak, with a 1M-token context window. The consumer chat product, meanwhile, carries no paid subscription tier at all.

Key Features of DeepSeek

• Free unlimited-style chat: the web chat and iOS/Android apps are free, with no subscription plan gating the current models.
• Thinking mode: switch on step-by-step reasoning for maths, logic and coding problems, and read the model’s working before its answer; the API supports both thinking and non-thinking modes.
• Web search in chat: the chat app can search the web to ground answers in current information rather than training data alone.
• Document upload: attach files and ask questions about them — summaries, extraction and comparison across long documents.
• 1M-token context: both current API models accept up to a million tokens of input and can return up to 384K tokens of output, per the official API documentation.
• OpenAI- and Anthropic-compatible API: the API speaks the formats developers already use, so existing code can switch to DeepSeek by changing the base URL and key.
• Automatic context caching: repeated prompt prefixes are billed at the far lower cache-hit rate automatically — input cache hits on the Flash model cost $0.003 per million tokens off-peak.
• Tool calls and JSON output: structured outputs, function calling and fill-in-the-middle completion are supported for agent and coding workflows.
• Open weights: DeepSeek publishes its models for self-hosting, so teams can run the same technology inside their own infrastructure.

How to Use DeepSeek

Most people need nothing more than the free chat:

1. Open the chat at chat.deepseek.com or install the mobile app, and create a free account.
2. Ask your question in plain language — writing, coding, analysis and translation all work from the same box.
3. Turn on thinking mode for hard problems where you want the reasoning shown, and use search when the answer needs current information.
4. Upload documents when you want DeepSeek to summarise, extract or compare file contents.
5. Developers: create an API key on the DeepSeek platform, top up a balance, and point any OpenAI-compatible client at api.deepseek.com.

How Much Does DeepSeek Cost?

According to DeepSeek’s official API documentation, the chat product is free and the API is billed per token with two rate periods: off-peak rates are half the peak rates (peak is 01:00–04:00 and 06:00–10:00 UTC on weekdays). The table below shows off-peak prices per 1 million tokens.

Model	Input (Cache Miss)	Input (Cache Hit)	Output	Context
deepseek-flash	$0.15	$0.003	$0.60	1M tokens
deepseek-v4-pro	$0.66	$0.022	$1.98	1M tokens

The Flash model (DeepSeek-V4.1-Flash) is the low-cost default for high-volume work; V4-Pro is the flagship reasoning model and also supports vision input on the Flash tier only, per the official model comparison. There is no monthly subscription for the API — you top up a balance and pay for what you use, and a granted balance, when present, is spent before paid credit.

Last verified: October 2026

DeepSeek Pros and Cons

Pros

• The chat product is completely free with no subscription tier — a rarity among frontier chatbots
• API prices are a fraction of Western rivals, especially with automatic cache-hit discounts
• Open-weight models can be self-hosted, avoiding vendor lock-in entirely
• Thinking mode exposes the reasoning process, which helps verify hard answers

Cons

• Data handling and jurisdiction questions make some companies cautious about sensitive workloads
• Peak-hour API pricing doubles the off-peak rates, so costs vary by time of day
• Enterprise support, SLAs and compliance packaging are thinner than at the big US providers
• The free chat can get busy at peak times, with slower responses or capacity limits

Who Should Use DeepSeek?

DeepSeek suits students and researchers who need a capable free assistant, developers building on a tight API budget, and teams who want to self-host open weights. Compared with xAI’s assistant in our Grok review, DeepSeek is the pick when price and open weights matter most, while Grok leans on real-time X data and paid tiers. For confidential client or regulated data, weigh the data-handling con above before sending anything sensitive.

Frequently Asked Questions

Is DeepSeek really free?

Yes. DeepSeek’s chat product on the web and in its iOS and Android apps is free to use, and DeepSeek does not advertise a paid subscription tier for consumers. Only the developer API costs money, and it is billed per token: the DeepSeek-V4.1-Flash model starts at $0.15 per million input tokens off-peak, with even cheaper cache-hit rates.

How much does the DeepSeek API cost?

According to DeepSeek’s official API documentation, off-peak pricing per million tokens is $0.15 input and $0.60 output for deepseek-flash, and $0.66 input and $1.98 output for deepseek-v4-pro, with cache-hit inputs as low as $0.003. Peak weekday hours (01:00–04:00 and 06:00–10:00 UTC) bill at double those rates, so scheduling batch work off-peak halves the bill.

Is DeepSeek open source?

DeepSeek releases its models as open weights, meaning the trained model files can be downloaded and run on your own hardware with no per-token fee — you pay only for the servers or GPUs. That openness is central to DeepSeek’s popularity with developers, although running the largest models yourself requires serious hardware despite the efficient mixture-of-experts design.

Which DeepSeek model should I choose?

Choose deepseek-flash for everyday chat, coding help and high-volume API work: it is DeepSeek’s low-cost model, supports vision input, and still offers the full 1M-token context. Choose deepseek-v4-pro when reasoning quality matters more than price — complex problem-solving, hard code and long agent runs — accepting output costs of $1.98 per million tokens off-peak instead of $0.60.

Final Verdict: Is DeepSeek Worth It?

DeepSeek is the easiest recommendation in AI chatbots right now: a genuinely free consumer product, an API priced far below the competition, and open weights for anyone who wants full control. The caveats are real but specific — data jurisdiction, thinner enterprise wrapping, peak-hour pricing — and none of them touch the core experience for individuals and cost-conscious developers. If you have not tried it, there is no financial reason not to.

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