GLM 5.3 Flash vs DeepSeek V4.1 Flash: specs, price, and who keeps your prompts

The Morse teamPublished October 27, 2026Facts checked October 27, 20268 min read

DeepSeek V4.1 Flash scores higher than GLM 5.3 Flash on every benchmark both companies report, while GLM 5.3 Flash costs less per output token, reads video and files as well as images, and its maker's app processes your chats in Singapore rather than China. Choose GLM 5.3 Flash if you want the cheaper, broader-input model and don't mind that its thinking stays on; choose DeepSeek V4.1 Flash if you want the stronger agent and coding scores and cheap cached input. On Morse you can use both without a Z.ai or DeepSeek account: GLM 5.3 Flash is on the Free plan and DeepSeek V4.1 Flash on Pro.

We read Z.ai's GLM 5.3 Flash launch post, API guide, price list, model card, and privacy policy, and DeepSeek's change log, price list, thinking-mode guide, both V4.1 Flash model cards (original and 1017), and privacy policy, all on October 27, 2026. Every benchmark number is the maker's own. Neither company has published a test of these two models against each other, so we set their separate results side by side and say where the setups differ.

GLM 5.3 Flash vs DeepSeek V4.1 Flash at a glance

As of October 27, 2026, from each maker's own pages.

Should you compare DeepSeek V4 Flash or V4.1 Flash?

V4.1 Flash. DeepSeek retired V4 Flash, a smaller 284B model, on September 10, 2026 (change log), yet most of the comparison pages we found for "glm 5.3 flash vs deepseek v4 flash" on October 27 still describe the old model.

The makers' own tables don't settle it either. Z.ai's launch post compares GLM 5.3 Flash with a column it labels "DeepSeek-V4-Vision-Exp," and the scores in that column (83.9 on Terminal Bench 2.1, 59.3 on DeepSWE, 57.7 on NL2Repo) are the ones DeepSeek's change log gives for V4 Flash Vision Exp, the experimental model of August 21 that it has since retired. DeepSeek's V4.1 Flash cards, in turn, compare against GLM-5.3, not GLM-5.3-Flash. So the benchmark table below uses each company's numbers for its own current model.

Which is better, GLM 5.3 Flash or DeepSeek V4.1 Flash?

DeepSeek V4.1 Flash, on every benchmark both companies publish, by margins from under 1 point to about 11, and wider for the 1017 update. These are each company's own runs of its own model, at maximum reasoning effort, with different harnesses in places. We haven't run them.

Sources: Z.ai's launch post and DeepSeek's V4.1 Flash and 1017 cards, read October 27, 2026. DeepSeek's 1017 card gives the original V4.1 Flash 65.4 on NL2Repo, not the 64.0 on its own card.

Terminal-Bench 2.1 is the one test both companies ran in the same harness, Claude Code, and there GLM 5.3 Flash scores 84.3 against 88.0. The closest race is Chartography, a chart-reading test. GLM 5.3 Flash has numbers DeepSeek doesn't publish: 78.4 on Toolathlon Verified and 1773 on GDPval-AA v2, the top scores in Z.ai's own table. Image tests don't line up. Z.ai reports 53.4 on BabyVision without saying tools were used, and DeepSeek reports 89.6 "with tools," so the two numbers can't be compared.

Which is cheaper, GLM 5.3 Flash or DeepSeek V4.1 Flash?

GLM 5.3 Flash for fresh input and output, DeepSeek V4.1 Flash for cached input. As of October 27, 2026, Z.ai charges $0.15 per million input tokens, $0.03 cached, and $0.50 output (Z.ai). DeepSeek charges $0.30, $0.006 on a cache hit, and $1.20 at peak, and half that off-peak (DeepSeek). Peak is 01:00 to 04:00 and 06:00 to 10:00 UTC on weekdays, except Chinese public holidays; every other hour is off-peak.

We worked out two jobs from those price lists, with no batch discounts:

DeepSeek's cache-hit price is a fifth of Z.ai's at peak and a tenth off-peak, which is why it wins jobs that reread a long context. DeepSeek also says V4.1 Flash's memory for long contexts takes about a quarter of what V4 Flash's did, at about 890 bytes per token (DeepSeek), while Z.ai's launch post says GLM 5.3 Flash's is "still slightly larger" than V4 Flash's. The two tokenizers don't count the same text the same way, and neither company compares them, so test your own prompts before you budget.

Where do chat.z.ai and chat.deepseek.com send your prompts?

To Singapore for Z.ai and to China for DeepSeek, and both apps keep your input as long as you have an account; our guides to GLM 5.3 Flash and whether DeepSeek is safe go through each policy.

Their training language differs. DeepSeek's privacy policy, last updated February 10, 2026, says it uses your data "to train and improve our technology, such as our machine learning models," and lists "the right to opt-out of using your Personal Data for training our models." Z.ai's privacy policy, last updated September 29, 2025, is vaguer. Its table of purposes names "when we train and improve our models" as one of Z.ai's legitimate interests, but the data listed against that purpose is account, communication, log, usage, and device information, and the policy describes no training opt-out. The prompts you type, which it calls User Content, appear in no row of that table, including the one for answering them, so the policy neither says Z.ai trains on your chats nor rules it out.

How to use GLM 5.3 Flash and DeepSeek V4.1 Flash on Morse

On chat.z.ai and chat.deepseek.com, every prompt lands on the maker's servers under your own account, kept until you delete that account. Morse gives you both models with no Z.ai or DeepSeek account, and keeps your history off its servers. GLM 5.3 Flash is one of the Free plan's models, with 15 messages a day and no card. DeepSeek V4.1 Flash is one of Pro's unlimited text models, at $19 a month ($17 billed yearly).

• Private, to put the same question to GLM 5.3 Flash and DeepSeek V4.1 Flash. A new chat opens in Private mode, which runs open-weight models like GLM and DeepSeek. Morse has zero data retention agreements with its inference, search, and other providers, so the host that runs the model keeps nothing of what you ask. When a provider confirms that on a reply, Morse checks the confirmation and refuses a reply that doesn't carry it; for the rest, it relies on the provider's commitment. Our explainer covers what zero data retention means.
• E2EE, for a question that should reach no one but the model. On Pro, GLM and DeepSeek models also run inside secure enclaves, operated by third-party providers rather than Morse. Before your message is sent, your browser verifies the enclave's hardware attestation against the versions pinned in the app and seals the message to that enclave alone, so what crosses Morse's servers is ciphertext they can't open. That holds as long as the enclave hardware and attestation work as designed. E2EE has no web search, so look things up in a Private chat. Our guide walks through how end-to-end encrypted AI chat works, step by step.
• Anonymous, to check either answer against Claude or GPT. Paste the prompt you gave GLM or DeepSeek into an Anonymous chat with Claude or GPT, and Morse sends it under its own account with your email, account, and IP address stripped off. Anthropic or OpenAI reads the prompt without knowing it's you, though under its own policy it may hold the message for a limited time to check for abuse.

In every mode, your chat history is stored only in your browser, encrypted, and locked when you sign out. Morse doesn't train AI on your chats, sell your data, or show ads (privacy policy), so there's no training opt-out to ask for. Clearing your browser deletes the history for good, and Morse can't recover it, so keep a copy of anything you need.

Which should you choose?

Z.ai's API guide says GLM 5.3 Flash's thinking "cannot be disabled," while DeepSeek's thinking-mode guide lets you switch V4.1 Flash's off or set it to low, high, or max effort.

• Choose GLM 5.3 Flash if you need video or file input, want the lower price on fresh input and output, or your work looks like the tool-use and office tasks where Z.ai reports its best scores, Toolathlon and GDPval. Its app processes data in Singapore.
• Choose DeepSeek V4.1 Flash if your work looks like DeepSeek's agent and coding tests, your jobs reread long cached contexts, you want replies up to 384K tokens, or you want thinking switched off for quick answers.
• Choose Morse if you want both models in one account, without sending either one's maker your email or keeping your chats on its servers.

Start free with GLM 5.3 Flash today, or send a first message from the Morse home page without an account; DeepSeek V4.1 Flash and E2EE chats come with Pro.

Morse publishes this comparison. We've tried to keep it fair; if something's wrong or out of date, email hello@trymorse.ai.

GLM is a trademark of Z.ai. Morse is not affiliated with or endorsed by Z.ai.

DeepSeek is a trademark of Hangzhou DeepSeek Artificial Intelligence Co., Ltd. Morse is not affiliated with or endorsed by DeepSeek.