Key Features

Two chat modes: Instant (V4-Flash) for sub-second replies and Expert (V4-Pro) for deep reasoning
DeepThink reasoning mode that exposes the full chain-of-thought before answering
Real-time web search toggle for current events, prices, and news
File upload (PDF, DOCX, TXT, code) with document Q&A and image vision
1M-token context window with up to 384K-token output (V4)
Open-weight models (V4, R1) downloadable and self-hostable for local/offline use
API deepseek-flash (V4.1-Flash) with peak/off-peak pricing since 2026-09-10 (off-peak is half of peak); cache-hit input is far cheaper
Free chat with no message caps or ads on chat.deepseek.com and the mobile apps

Pros & cons

Pros

Genuinely free unlimited chat with frontier-grade reasoning, web search, and file upload at $0
API pricing roughly 90-95% cheaper than comparable Western frontier models
Open weights let teams self-host for privacy or run models offline
DeepThink mode is strong on math, multi-step logic, and code relative to its cost

Cons

Hosted chat stores data on servers in China, subject to Chinese law; flagged as a national-security risk and banned for government use in several US states, Italy, South Korea, Taiwan, Australia, and Denmark
Heavy political censorship: refuses or deletes answers on Tiananmen, Taiwan, Xinjiang, and Xi Jinping (~85% of politically sensitive prompts), with an app-layer filter that can erase a reply mid-stream
No formal enterprise tier, SSO, audit logs, or no-telemetry option on the hosted service
Reasoning (Expert/DeepThink) mode is slow, often 15-60 seconds per answer
Smaller third-party ecosystem and fewer integrations than ChatGPT, Gemini, or Claude

Pricing

Plan	Details
Free	Unlimited free chat on web and mobile: Instant + Expert modes, DeepThink reasoning, web search, file upload, and image vision, with no message caps or ads. API new accounts get ~5M free tokens valid 30 days.
Starter	Chat (web/app): Free
Pro	API deepseek-flash (V4.1-Flash), per 1M tokens (off-peak / peak): input cache miss $0.15 / $0.30, input cache hit $0.003 / $0.006, output $0.60 / $1.20

Also: prices effective 2026-09-10 04:00 UTC. Peak hours are 01:00-04:00 and 06:00-10:00 UTC, Monday to Friday, excluding Chinese public holidays; all other hours (including weekends and those holidays) are off-peak at half the peak rate. There is no separate V4-Pro paid tier: since 2026-09-14 04:00 UTC, deepseek-v4-pro requests are served by V4.1-Flash at Flash prices until V4.1-Pro launches. Legacy names deepseek-v4-flash and deepseek-v4-flash-vision-exp are retired and routed to V4.1-Flash. No consumer subscription tier exists. Per DeepSeek news post 2026-09-10 (api-docs.deepseek.com/news/news260910).

Tips & Best Practices

Toggle DeepThink only for hard math, logic, or code; leave it off for simple questions to avoid 15-60s waits
Turn on the web search toggle whenever the question depends on recent or time-sensitive data
For confidential business, medical, or legal data, self-host the open weights instead of using the hosted chat
Run batch or flexible API jobs off-peak to pay half the peak rate: peak is 01:00-04:00 and 06:00-10:00 UTC on weekdays; all other hours, weekends and Chinese public holidays are off-peak.

Final Recommendation

DeepSeek is a freemium AI tool best suited for Budget-conscious developers and indie builders, Students and researchers needing math/logic reasoning.

DeepSeek

Key Features

Pros & cons

Pros

Cons

Pricing

Tips & Best Practices

Final Recommendation

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Key Features

Pros & cons

Pros

Cons

Pricing

Tips & Best Practices

Final Recommendation

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