DeepSeek

Open-source frontier reasoning that just leveled up with V4 — pay per token

Why we recommend DeepSeek

DeepSeek is a relatively young Chinese AI lab that stepped into the first tier with DeepSeek-V3 / R1, and in August 2026 launched its next-gen flagship DeepSeek-V4 (V4-Flash / V4-Pro). Three things stand out:

Open source + commercial friendly — DeepSeek ships model weights, training details, and inference code under a permissive MIT license. You can use, modify, fine-tune, and self-host the model commercially without paying anyone — a sharp contrast to "open weights, no commercial use" competitors.

Strong reasoning — The new DeepSeek-V4-Pro pushes well past R1 on math, code, logic, and Agent benchmarks, and natively supports the Responses API and Codex. R1 still returns chain-of-thought (CoT) output and remains a solid fit for multi-step reasoning and agent orchestration.

Cost-controlled — DeepSeek bills on a peak/off-peak schedule: peak hours are double, and off-peak (anything outside UTC 01–04 and 06–10) is half price. The flagship V4-Flash runs off-peak at $0.22 input / $0.66 output (peak doubles to $0.44 / $1.32, per 1M tokens, cache miss); the previous-gen V3 stays at ¥1/¥2 and R1 at ¥4/¥16. Overall still far below closed-source frontier models, great for high-volume workloads.

In practice, platform.deepseek.com is reliably reachable from inside China, the API is 100% OpenAI-compatible (existing code can switch with one baseURL change), and top-ups work via WeChat / Alipay without a credit-card gate.

Billing model note — DeepSeek does not offer a fixed Coding Plan subscription; it's pure pay-per-token. The "plans" above are illustrative pricing rows summarizing the public per-token rates (current flagship V4-Flash / V4-Pro, with previous-gen V3/R1 kept for reference), not tiers you can subscribe to. Peak/off-peak pricing takes effect 2026-08-16 16:00 UTC. Real billing is on the platform.deepseek.com console.

If your project is high-volume, budget-sensitive, and needs frontier reasoning, DeepSeek-V4 is one of the strongest cost-per-quality plays on the market right now.