DeepSeek

DeepSeek is an AI assistant and model family from the Chinese AI company DeepSeek. Its chat app and website are free, with a reasoning mode and file uploads, and its API is known for very low per-token prices. It is popular with developers and with people who want a capable assistant without a subscription.

Quick facts

• Made by: DeepSeek, an AI company based in Hangzhou, China, founded in 2023
• Free plan: Yes. The app and website are free, and there is no paid consumer subscription.
• Paid use: Only through the API, which is billed per token
• Works on: Web, iOS and Android, with an API for developers
• Pricing last checked: October 2026, using several recent published sources. API prices and model names have changed more than once this year, so confirm on DeepSeek’s official API pricing page.

What DeepSeek is best at

• Free everyday chat: questions, writing help, file uploads and web search at no charge.
• Reasoning tasks: a DeepThink mode for maths, logic and step-by-step problems.
• Coding help: code generation, explanation and debugging.
• Low-cost API access: among the cheapest per-token rates for capable models, with large context windows of up to about one million tokens.
• Openness: DeepSeek has published open weights for some models, which developers can study and run themselves, subject to each model’s licence.

Plans and pricing

Prices are charged per million tokens, with cached input billed at a much lower rate and off-peak hours discounted. Rates have changed several times in 2026. The V4 models launched in April at lower prices, and the older deepseek-chat and deepseek-reasoner names reached their retirement deadline in July, so check which model name and rate apply to you. Confirm everything on DeepSeek’s official page.

Best for

• Individuals who want a capable free assistant.
• Developers and startups who need a low-cost API for high-volume work.
• Users who care about open weights and self-hosting options.

Less suited to

• Sensitive, regulated or confidential material. Check where the data is processed and what your organisation allows, since some governments and companies restrict its use.
• Anyone who needs a mature set of business admin controls and a support contract.
• Topics where answers may be shaped by content restrictions, so compare results with another assistant on sensitive subjects.

How to get started

1. Open the website or app and sign in to start chatting for free.
2. Try DeepThink on a problem that needs several steps, and read the reasoning it shows.
3. For the API, create an account, add credit and test with a small number of requests to see real costs.
4. Use cached prompts where possible, because cached input is much cheaper.
5. Keep private or regulated data out of the free app unless you have confirmed it is allowed.

Prompt ideas to copy

Think step by step. Solve this problem, show your reasoning, then give the final answer in one sentence: [problem]

Review this code for bugs and performance problems. List each issue with a short fix and why it matters.

[paste code]

Summarise the attached document in five bullet points, then list three questions it leaves unanswered.

Convert this SQL query to [database name] and explain any differences in behaviour.

Limitations and things to watch

• Answers can be wrong, so verify important facts, code and calculations.
• API prices, model names and peak and off-peak rules change often.
• Data handling and access rules differ by country and organisation, so check them before sharing anything private.
• The free app has no published uptime or support guarantees.

Alternatives

Compare ChatGPT, Claude, Gemini and Grok. For coding in your editor, see GitHub Copilot and Cursor.