If you searched “deepseek vs bing chat” expecting two products with the same shape, the first thing to flag is that “Bing Chat” is no longer the official name. On November 15, 2023, Microsoft announced that Bing Chat itself was being rebranded as Microsoft Copilot. What sits at copilot.microsoft.com today is the same lineage, but the surface area is now Microsoft’s broader Copilot ecosystem. DeepSeek, by contrast, ships open-weight models and a thin chat UI on top.

This article compares the two as most readers actually use them: a free conversational AI that searches the web (Copilot, formerly Bing Chat) versus DeepSeek’s V4 chat plus its API. I’ll cover models, pricing, coding, reasoning, privacy, and where each one wins.

The verdict up front

For everyday web search with citations and tight integration into Windows, Edge and Microsoft 365, Microsoft Copilot (the product formerly branded Bing Chat) wins. It plugs into your operating system, your Office documents, and a search index DeepSeek does not have.

For API access, transparent per-token pricing, open weights, long-context document work, and coding-heavy workflows, DeepSeek wins — by a wide margin on cost and a measurable margin on several coding benchmarks. DeepSeek V4 Pro released April 2026: 1.6T parameters, 1M token context, Terminal-Bench 67.9% vs Claude 65.4%, LiveCodeBench 93.5% vs 88.8%, SWE-bench 80.6%.

The honest answer is that they solve different problems. Copilot is an assistant layered on top of Microsoft’s stack. DeepSeek is a model family with an OpenAI-compatible API. If you only want one of those, the choice picks itself.

At-a-glance comparison

What “Bing Chat” actually means in 2026

Before any benchmark talk, the naming needs to be straight. Microsoft said Bing Chat and Bing Chat Enterprise would “simply become Copilot,” and that the product would become generally available beginning December 1, 2023, reinforcing that this was not merely a UI rename but a packaging and access reset. The standalone copilot.microsoft.com domain is the spiritual successor to bing.com/chat, and the underlying tech now uses a routing layer. Microsoft began rolling out GPT‑5 to Bing and Copilot in August 2025. This upgrade introduced a new Smart Mode, a server‑side “model router” that dynamically decides which AI model to use depending on the complexity of the query. Quick queries are handled by a lightweight, high‑speed model. Complex reasoning tasks are escalated to GPT‑5.

So when readers ask about deepseek vs bing chat, the comparison is really DeepSeek V4 versus Microsoft’s consumer Copilot — a free product backed by OpenAI models, integrated with Bing search, and surfaced in Edge and Windows.

Models and architecture

DeepSeek V4

DeepSeek’s current generation went live with two tiers on April 24, 2026. They just dropped the first of their hotly anticipated V4 series in the shape of two preview models, DeepSeek-V4-Pro and DeepSeek-V4-Flash. Both models are 1 million token context Mixture of Experts. Pro is 1.6T total parameters, 49B active. Flash is 284B total, 13B active. They’re using the standard MIT license. The default context window on both is 1,000,000 tokens with output up to 384,000 tokens. For deeper specs see our DeepSeek V4 page.

Thinking mode is a request parameter on either V4 model, not a separate model ID. The legacy deepseek-chat and deepseek-reasoner IDs still work — both currently route to deepseek-v4-flash — but they retire on 2026-07-24 at 15:59 UTC.

Microsoft Copilot

Copilot does not publish a parameter count because Microsoft does not own most of the underlying weights — they are OpenAI’s. The visible architecture is the router and the surface integrations. On October 1, 2024, Microsoft announced a major overhaul of Copilot for personal accounts, which included UI changes, fully separating it from Bing, the addition of features such as Copilot Voice, Copilot Vision, and Think Deeper (a reasoning model), and the launch of Copilot Labs, an early access program exclusive to Microsoft Copilot Pro.

Coding

This is where the gap is largest, and clearly in DeepSeek’s favour for raw model capability. V4-Pro is genuinely competitive with GPT-5.4 and Claude Opus 4.6 across most categories, and beats both on coding benchmarks. Copilot, the consumer chat product, is fine for explaining a stack trace or rewriting a regex, but it isn’t pitched as an agentic coding tool — that’s GitHub Copilot, a different product line.

If you want hands-on coding, the workflow comparison looks like this:

• DeepSeek: point your IDE at the API. We cover the setup in our DeepSeek with VS Code guide. For a deeper API walk-through see DeepSeek API getting started.
• Copilot: open the chat panel, paste a snippet, ask a question. Useful, but you can’t pipe it through scripts without a separate Microsoft 365 or GitHub product.

For a head-to-head on coding-specific tooling, see DeepSeek Coder vs Copilot.

Reasoning and long context

DeepSeek V4 supports thinking mode on both tiers via reasoning_effort. The response returns reasoning_content alongside the final content. This is configurable per request, which matters when you want the cheaper non-thinking path for trivia and the more expensive thinking path for proofs. On Putnam-200 Pass@8 with minimal tools, V4-Flash-Max scores 81.0, compared to 35.5 for Seed-2.0-Pro, 26.5 for Gemini-3-Pro, and 26.5 for Seed-1.5-Prover. On the frontier Putnam-2025 setup, V4 reaches a proof-perfect 120/120.

Copilot’s reasoning mode is “Think Deeper”. In February 2025, Microsoft announced that Copilot Voice and Copilot Think Deeper, which uses OpenAI’s o1 model, would be free for all Copilot users with unlimited access. Whether it still uses o1 specifically by the time you read this is worth checking on Microsoft’s own page — model labels behind app toggles change frequently.

On context length, the difference is structural. DeepSeek V4 ships with a default 1M-token window on both Pro and Flash. Microsoft does not publicly document a per-request token ceiling for free Copilot. For very long documents or multi-file code review, point-blank: DeepSeek is the better tool.

Pricing — the part where DeepSeek really pulls ahead

Microsoft Copilot’s consumer chat is free; on January 15, a subscription service, Microsoft Copilot Pro, was announced, providing priority access to newer features for US$20 per month. There is no public pay-per-token chat-completions API for the Copilot consumer chatbot.

DeepSeek’s V4 pricing as of April 2026 (see DeepSeek API pricing):

Off-peak discounts ended on 2025-09-05 and were not reintroduced for V4. Context: OpenAI’s GPT 5.4 costs $2.50 per 1M input tokens and $15.00 per 1M output tokens, while Claude Opus 4.6 costs $5 per 1M input tokens and $25 per 1M output tokens. As such, DeepSeek — at least on benchmarks — delivers similar performance to these models at a 50-80% cost reduction.

Worked example — V4-Flash for a customer-support bot

Imagine 1,000,000 calls a month with a 2,000-token cached system prompt, a 200-token user message, and a 300-token reply. On deepseek-v4-flash:

• Cached input: 2,000 × 1,000,000 = 2,000,000,000 × $0.028/M = $56.00
• Uncached input: 200 × 1,000,000 = 200,000,000 × $0.14/M = $28.00
• Output: 300 × 1,000,000 = 300,000,000 × $0.28/M = $84.00
• Monthly total: $168.00

The same workload on deepseek-v4-pro at $0.145 / $1.74 / $3.48 lands at $1,682.00. Pick a tier deliberately. Copilot has no equivalent priced product on the consumer side, which is exactly the point: you cannot embed Copilot Chat in a SaaS pipeline.

Calling DeepSeek from code

DeepSeek’s API is OpenAI-compatible. Chat requests hit POST /chat/completions, the OpenAI-compatible endpoint, against https://api.deepseek.com. An Anthropic-compatible surface is also available at the same base URL. The API is stateless — your client must resend the conversation history with every request, unlike the web chat which keeps session history for you.

A minimal Python example using the OpenAI SDK:

from openai import OpenAI

client = OpenAI(
    base_url="https://api.deepseek.com",
    api_key="YOUR_KEY",
)

resp = client.chat.completions.create(
    model="deepseek-v4-flash",
    messages=[
        {"role": "system", "content": "You are a helpful assistant."},
        {"role": "user", "content": "Summarise this changelog in five bullets."},
    ],
    temperature=1.3,
    max_tokens=600,
)
print(resp.choices[0].message.content)

For thinking mode, add reasoning_effort="high" and extra_body={"thinking": {"type": "enabled"}}. JSON mode (response_format={"type": "json_object"}) is designed to return valid JSON, not guaranteed — your prompt should include the word “json” plus a small example schema, and you should set max_tokens high enough to avoid truncation. Other parameters worth knowing: top_p, streaming via stream=true, tool calling, FIM completion (Beta, non-thinking only), and context caching that automatically applies the cache-hit price tier when the API detects repeated prefixes.

Privacy and data handling

This is where most enterprise readers actually make the call.

Microsoft Copilot runs on Azure, with a tiered data regime. Microsoft said signed-in users with an Entra ID would get commercial data protection at no additional cost. Microsoft carefully preserved a separation between consumer and enterprise protection models. Consumer Copilot later received a different data-use policy, while commercial accounts continued to benefit from stronger guarantees around storage, access, and model training. If you are a free consumer user, treat your prompts as training data unless you sign in with a work Entra ID.

DeepSeek processes conversations on servers subject to Chinese law. There has been regulatory pushback in some jurisdictions: Italy’s Garante ordered blocking of the DeepSeek app in January 2025, and several US states (Texas, New York, Virginia among them) restricted DeepSeek on government devices. There is no federal US ban as of this article’s verification date. For a fuller treatment see our notes on DeepSeek privacy and the running tracker at DeepSeek US restrictions.

If your data cannot leave your network at all, only DeepSeek offers a clean answer: download the open weights and self-host. See install DeepSeek locally.

Ecosystem and integrations

Copilot’s strongest pitch is that it is everywhere a Windows or Microsoft 365 user already is. Windows users now access Copilot through multiple entry points: the taskbar icon, keyboard shortcuts (Windows Key + C), or voice activation. The integration allows Copilot to interact with system settings, file management, and installed applications in ways that Bing Chat never could. Users can ask Copilot to change display settings, summarize documents, or control media playback without leaving their current workflow. If you live in Outlook, Word, Excel, or Teams, that gravity is hard to argue with.

DeepSeek’s ecosystem is built around the API and open weights — Hugging Face, Ollama, LangChain, LlamaIndex, vLLM. There is no native Word add-in. There is, however, a thriving third-party tooling layer; for Python and JS specifically see DeepSeek Python integration and DeepSeek Node.js integration.

When to pick which

Pick Microsoft Copilot if

• You want a free chatbot that also searches the web with citations.
• You spend your day in Windows, Edge, or Microsoft 365.
• You are an enterprise that already has Entra ID and wants commercial data protection by default.
• You don’t need to embed AI in your own product or pipeline.

Pick DeepSeek if

• You need a programmatic API with predictable per-token pricing.
• You work with long documents or large codebases — the 1M-token window is real and useful.
• You are doing serious coding or formal-math work and want frontier-tier benchmarks at a fraction of the spend.
• You need to self-host on open weights for compliance, air-gap, or research reasons.

Alternatives worth comparing

Two more pairings are likely on your shortlist: DeepSeek vs ChatGPT (because Copilot is essentially OpenAI underneath, ChatGPT is the closer like-for-like) and DeepSeek vs Perplexity (because Perplexity is purpose-built for the citations-and-search use case Copilot is best at). For the broader landscape see DeepSeek comparisons.

Last verified: 2026-04-25. DeepSeek AI Guide is an independent resource and is not affiliated with DeepSeek or its parent company. Model IDs, pricing and API behaviour change; check the official DeepSeek documentation and pricing page before committing to a production decision.