SumizAI vs DeepSeek

What DeepSeek is

What DeepSeek is

DeepSeek is a Chinese AI startup and the name of its flagship chat assistant, built around the open-weight R1 model family released on January 20, 2025. R1 drew enormous industry attention because it delivered results comparable to top reasoning models from OpenAI (o1) at a much lower training and inference cost, sparking a loud market-wide debate about the real cost of developing large language models.

Key features

R1 is a reasoning model — before answering, it generates a visible chain of intermediate steps, which helps with math, coding, and logic tasks. The model weights are open source under the MIT licence, allowing free commercial and academic use and letting anyone build their own smaller, distilled versions from the full model. The DeepSeek-R1-0528 update from May 2025 improved benchmark results, reduced hallucinations, and added support for function calling and structured JSON output.

Who it's for

DeepSeek appeals both to everyday users looking for a free, capable chat assistant and to developers and researchers who want to run or fine-tune an open reasoning model on their own infrastructure, without paying for a closed provider's API.

Use cases

In practice, DeepSeek works well for solving complex math and coding problems step by step, as a free alternative to paid reasoning models for everyday work, and as a base for building custom, fine-tuned models for teams with access to GPU infrastructure.

Pricing and business model

The DeepSeek chat app is free on a freemium basis, and the R1 model weights themselves are fully open and free to download and run locally — the only cost is the hardware or cloud infrastructure needed to host the model yourself.

Limitations and what to watch for

As a product of a Chinese company, DeepSeek is subject to local content and moderation regulations, which can affect answers on political or historical topics — worth factoring in when choosing a tool for use cases requiring full neutrality.

AI notes built by hand from reasoning answers

People using DeepSeek to solve complex problems often want to keep not just the final answer but the visible reasoning chain too, as ai notes documenting the model's train of thought — with no built-in archive, building such a collection of ai notes takes regular, manual export from the chat window.

Community around the open model weights

Releasing R1's weights under the MIT licence inspired dozens of derivative projects and integrations, from local chat front-ends to notebook plugins supporting ai notes generated by a local run of the model with no queries sent to DeepSeek's cloud.

The debate over data security in Chinese AI models

Institutional users often ask whether conversations run through DeepSeek's cloud version could be stored on servers subject to Chinese law — one reason some teams choose to run the open model weights locally instead of using the hosted chat version, keeping their ai notes entirely within their own infrastructure.

Impact on competitors' API pricing

After R1's launch, several major closed-model providers cut their API prices or rushed out cheaper variants of their models, showing how strongly a single release can shift the entire pricing structure of the large-language-model market.

Availability through API and third-party integrations

DeepSeek also offers an API compatible with a widely used industry format, making it easier to integrate the model with existing developer and notes tools without writing custom connecting code.

Fine-tuning the model for specialized tasks

R1's open weights let research teams fine-tune the model further for specific domains — law, medicine, engineering — something closed models available only through an API without weight access don't offer. That freedom attracts teams who want full control over the model's final behaviour, not just prompt-level tuning.

AI notes from DeepSeek reasoning sessions

DeepSeek offers no built-in archive of past conversations — every chat session, even one with a visible reasoning chain, ends inside the chat interface, and a worthwhile answer someone wants to keep as an ai notes entry has to be copied by hand into a separate notes app.

Impact on the language model market

Releasing R1 under an open licence at a low training cost pushed many other providers to revisit their pricing and open-weight strategies, and the debate over DeepSeek's actual training cost became one of the loudest topics in the AI industry in 2025.

Distilled versions of the model

Beyond the full R1, DeepSeek released smaller, distilled variants that can run on more modest hardware while retaining part of the original's reasoning ability — lowering the barrier to entry for anyone wanting to experiment with reasoning models locally.

What's worth checking before choosing

Before using DeepSeek, check the current privacy policy on conversation storage, and whether you want the cloud version or to self-host the open model weights instead.

Running the model on your own hardware

The full R1 model needs serious hardware — GPUs with a large amount of memory — but smaller, distilled variants can run locally on much more modest machines, making experimenting with an open reasoning model accessible to individual enthusiasts too, not just teams with an enterprise-grade cloud budget. Choosing between the full and a distilled variant is a trade-off between answer quality and hardware availability that everyone has to weigh against their own resources.

Bottom line

DeepSeek is a free, capable chat assistant built on the open R1 reasoning model, which reshaped the global conversation about AI training costs. Anyone who wants worthwhile answers from such conversations to land automatically in a searchable archive of these notes should consider a tool built around that workflow.

Comparison with SumizAI

DeepSeek and SumizAI play different roles in the AI ecosystem. DeepSeek is a model provider and chat app with no lasting notes archive. SumizAI is a notebook where answers worth keeping automatically become these notes — Markdown files in a vault you own — with the AI model connected through your own API key to one of seven providers (though not DeepSeek directly at the moment). Anyone who wants a free, capable reasoning model to talk to will pick DeepSeek; anyone who wants worthwhile answers from those conversations to build a lasting archive of these notes will find SumizAI the better-fitting tool.

That is our reading of the record. For AlternativeTo's own wording, see its page for DeepSeek — the facts above were read on 2026-08-16.

DeepSeek in depth

A model lab that also runs a consumer chat

DeepSeek is unusual among the assistants in this category because the chat window is the smaller half of the business. Behind it sits DeepSeek Artificial Intelligence Co., Ltd., a Chinese research company that trains its own frontier models and publishes technical reports for each generation — V3, R1, V3.1, V3.2 and now V4 all have their own research pages. What most people meet is the free web chat and the mobile apps for iOS and Android; what developers meet is a token-billed API; and there is a third product, DeepSeek Harness, sitting alongside them. The corporate footprint is visible in the site footer, which carries Zhejiang ICP filings, and the interface is offered in Chinese and English with the assistant itself handling well over thirty languages.

The company reached wide attention because it released capable models under permissive terms while charging far less than the American labs for API access. The catalogue records the licence as MIT, which is what makes the open-weights claim meaningful: a user in the comments describes it as genuinely open source rather than open in name, and open weights are why the product can be run outside DeepSeek's own servers by anyone with the hardware. That is also the only sense in which the catalogue's "works offline" tag is defensible — the hosted chat certainly needs a connection.

V4, and what the current models actually are

The generation on offer now is V4, in two variants that the API documents name precisely: deepseek-v4-flash, build DeepSeek-V4-Flash-0731, and deepseek-v4-pro, build DeepSeek-V4-Pro-0813. The catalogue notes their arrival in April 2026 as the first major update in more than a year, which fits a lab that ships infrequently and substantially rather than continuously. DeepSeek's own announcement for the Pro release emphasises stronger agent behaviour plus support for the Responses API and Codex integration, and states that it went live simultaneously on the web, in the app and through the API.

Both variants share a context window of one million tokens and a maximum output of 384,000 tokens, which is at the generous end of the market and directly addresses one of the complaints in the reviews. Both support a thinking mode and a non-thinking mode, with thinking on by default. Both do structured JSON output, tool calls, the Responses API and an Anthropic-compatible API, plus chat prefix completion in beta; fill-in-the-middle completion is beta as well and works only in non-thinking mode. The endpoints are deliberately drop-in: api.deepseek.com speaks the OpenAI format and api.deepseek.com/anthropic speaks Anthropic's, so existing client code usually needs a base URL change rather than a rewrite.

Pricing, including the part that catches people out

The chat is free with no usage cap that DeepSeek publishes, which is the single biggest reason casual users pick it. The API is billed per token, and the rate card has a wrinkle that materially changes the arithmetic: prices vary by time of day. Peak hours are 01:00 to 04:00 and 06:00 to 10:00 UTC; everything outside those windows is off-peak and costs exactly half.

• Flash, per million tokens: input on a cache hit $0.007 off-peak and $0.014 at peak; input on a cache miss $0.22 off-peak and $0.44 at peak; output $0.66 off-peak and $1.32 at peak.
• Pro, per million tokens: input on a cache hit $0.022 off-peak and $0.044 at peak; input on a cache miss $0.66 off-peak and $1.32 at peak; output $1.98 off-peak and $3.96 at peak.

Note how large the cache-hit discount is: roughly thirty times cheaper than a cache miss on input. Anyone sending a long, stable system prompt should design for context caching before worrying about anything else. Concurrency is capped by model — 2,500 for Flash, 500 for Pro. Billing draws down a prepaid or granted balance, granted first, and DeepSeek states openly that prices may change. They already have: the catalogue notes a substantial API price rise announced by the company, so the figures above are a snapshot rather than a promise. The catalogue's own pricing field, showing a one-time purchase of $150 to $300 or a $10 to $20 monthly subscription, does not correspond to anything DeepSeek sells and should be disregarded — it appears to be a stray entry rather than a real plan.

What users say, split fairly

Reception is mixed and the numbers show it: 177 likes but an average of 3.3 out of 5 across fifteen ratings, with ten written reviews, and 3.99 on Apple's App Store. The value argument dominates the positive side. One reviewer got usable results on a custom CPU instruction set and assembly generation, a genuinely demanding task, and called the openness real. Others describe it as among the strongest models available and repeatedly return to the same point: the ratio of capability to cost. Free unlimited chat, support for several file types and solid handling of short documents come up often.

The criticism is specific and consistent enough to take seriously. Long conversations degrade, and large PDF uploads are reported as a weak spot — a complaint that predates the one-million-token context, so it is worth retesting rather than assuming. Several users say the product has not evolved as fast as rivals and that agentic behaviour, inference speed and image generation all lag. The absence of a canvas-style mode for drafting long documents is named directly. And the most consequential complaint is political: users report heavy censorship of China-related subjects, which is a structural feature of a service hosted in that jurisdiction rather than a bug that will be patched. Anyone whose work touches contested history, regional politics or human rights should assume the hosted chat will not engage, and should look at running the open weights themselves if the model's quality is what they want.

There is also a reputational dispute in the comments: allegations that DeepSeek trained on output from OpenAI in 2024 and from Anthropic in 2026. These are allegations reported by users, not findings, and at least one commenter pushes back by noting that large labs generally are accused of unauthorised use of training data. It is recorded here because it appears in the source material, not as an established fact.

Fit, and the questions to settle first

DeepSeek suits developers who want frontier-adjacent capability at a fraction of the usual token price, teams that can schedule batch work into off-peak hours and halve their bill, and anyone who needs the option of running weights on their own infrastructure rather than depending on a vendor's uptime. The OpenAI- and Anthropic-compatible endpoints make it cheap to evaluate against whatever you use now.

It is a poor fit where the hosted service's jurisdiction is itself the problem — regulated industries and public-sector procurement in Europe and North America will have questions about data location that the free chat does not answer. It is a poor fit for users who need a polished document-drafting surface, since the missing canvas mode is a real gap. And it is a poor fit for anyone who needs price stability, given the company's stated right to adjust rates and its recent history of doing so.

Where SumizAI fits

SumizAI is a place to work with several models side by side rather than a competitor to a model lab. If DeepSeek's price is attractive but you want the option of checking a sensitive answer against a model hosted elsewhere, running both in one interface is the practical arrangement.

Product page: deepseek.com

What SumizAI is

A note-taking application built around a conversation with an AI model. You ask a question, the answer streams back, and the answers worth keeping become Markdown notes — filed into a vault that is a folder on your own disk.

A vault is a directory holding base.md, a generated table of contents up to six levels deep, and a notes/ folder with one .md file per note. Before a note is written it is checked against the ones already there, so the fourth note about the same idea gets merged instead of added. Links between notes are ordinary Markdown links to files that exist.

The model is never ours: you bring your own API key to one of seven providers — Anthropic, OpenAI, Gemini, Groq, OpenRouter, a local Ollama or your own server — and pay that provider directly. A question sends the table of contents plus at most five relevant notes within a 24,000-character budget, and the app shows you which five it used.

Every answer kept this way becomes one of these ai notes, ready to search again months later without hunting back through old chats.

Side by side

Where they differ

• DeepSeek is a place to have the conversation. SumizAI is not a chatbot — the conversation is the input, not the product. What comes out of it is a .md file with a title, a place in base.md and a duplicate check against the notes already in the vault. If you only want to talk to a model, you do not need SumizAI.
• DeepSeek is open source (MIT), and SumizAI is not. If reading the source is what decides it for you, that is a real argument for DeepSeek. The guarantee SumizAI offers instead is structural rather than legal: the notes are Markdown files in a folder you chose, so they open in any editor whether or not the application is running.
• DeepSeek is freemium: there is a free tier and a paid one, and the line between them is the thing to read before committing. SumizAI has one plan at a dollar a month, so there is no feature held back for a higher tier — and an unpaid account still opens and exports every vault it already has.
• AlternativeTo's description of DeepSeek does not mention Markdown, so check what format your notes end up in before you fill it up. SumizAI writes standard .md files to a folder you picked, and an unpaid account can still export all of them.
• DeepSeek also does tasks. SumizAI does not — no boards, no due dates, no projects. It files knowledge, not work.
• DeepSeek runs in the browser. SumizAI is a desktop and mobile application, and on the desktop the vault is a folder on your own disk rather than a document in someone's cloud.

Which one to pick