DeepSeek V4 Pro vs Claude Sonnet 5

Specs side by side

Price per token

Prices exclude taxes and are charged from your prepaid USD balance. Both models work through the same key, in the OpenAI-compatible /v1/chat/completions endpoint. Failed generations cost nothing.

Pick DeepSeek V4 Pro when the model reads a lot, writes little and budget matters: its input is about 8 times cheaper than Claude Sonnet 5, and a typical chat workload comes out about 4 times cheaper. Pick Claude Sonnet 5 for Claude Code and coding agents where you want Anthropic's model with tools and the /v1/messages endpoint. If price is why you are looking at DeepSeek, also check V4.1 Flash, which DeepSeek itself rates above V4 Pro.

Key differences

• Price. DeepSeek V4 Pro costs $2.35 / $4.70 per 1M tokens, Claude Sonnet 5 costs $3.24 / $16.20 per 1M tokens. Sonnet is about 8 times more on input and about 2.9 times more on output. On the 1,000-reply row above that works out to roughly 4 times.
• Input to output ratio. On V4 Pro output costs about 14 times its input rate, on Sonnet 5 times. Long generations eat into DeepSeek's lead; long prompts widen it.
• Reply length. V4 Pro returns up to 384,000 tokens, Sonnet up to 128K. Context in both: 1,000,000 tokens.
• Endpoints and tools. Sonnet works on /v1/chat/completions and /v1/messages, so it runs in Claude Code. V4 Pro only on the OpenAI-compatible endpoint: Cursor, Cline, n8n.
• Open weights. V4 Pro is a MoE model with 1.6 trillion parameters (49 billion active per token) and published weights. Sonnet 5 is closed.
• Thinking. DeepSeek offers three effort levels: low, high and max. Sonnet 5 has adaptive thinking on by default and rejects non-default temperature, top_p and top_k.
• Model lifecycle. DeepSeek first announced it would redirect V4 Pro traffic to V4.1 Flash, then reversed that. A V4.1 Pro has been mentioned without a date, so plan for a migration.

When to pick DeepSeek V4 Pro

• Analysis of repositories and document sets where input is large and the answer short.
• Very long outputs, such as full reports beyond 128K tokens.
• Agent workflows already tuned on V4 Pro.
• Comparing an open-weight model with a closed one on your own data.

When to pick Claude Sonnet 5

• Daily work in Claude Code: tests, fixes, new features.
• Agents that plan and call tools over many steps. Anthropic calls Sonnet 5 its most agentic Sonnet so far.
• Debugging legacy code down to the root cause.
• Code written for the Anthropic SDK.

Both sit behind one key and one balance, so the easiest way to decide is to run the same tasks through both and compare the results and the usage field. The code for that test is in One LLM API in Python and Node, and the budget-model ranking is in Cheapest LLM API in 2026.

FAQ

DeepSeek V4 Pro or Claude Sonnet 5 for coding?

For Claude Code, Sonnet 5, because of the two only Sonnet works through /v1/messages. In Cursor or your own agent you can use both and compare them on a dozen tasks from your repository. I have not tested this pair on my own code, so I will not name a winner.

How much cheaper is DeepSeek V4 Pro than Sonnet 5?

About 8 times on input, about 2.9 times on output, and about 4 times on a typical chat (1,500 input tokens, 400 output). Current rates: $2.35 / $4.70 per 1M tokens and $3.24 / $16.20 per 1M tokens.

Can I use DeepSeek V4 Pro in Claude Code?

Not through Jantaris. The Anthropic-compatible endpoint that Claude Code uses serves Claude models only. Connect DeepSeek in OpenAI-compatible tools instead.

Is V4 Pro better than DeepSeek V4.1 Flash?

Not by DeepSeek's own account: V4.1 Flash does better in tests by several parties and costs less. V4 Pro makes sense where your prompts and evals were built around it.

Do I need a DeepSeek account?

No. You pay from your Jantaris balance with the same key you use for Claude and every other model. Jantaris does not use your prompts or outputs to train models.