GLM 5.3 Flash vs DeepSeek V4 Flash.

The site's default all-rounder against the cheapest heavy hitter.

GLM 5.3 Flash is the model UsingOpen opens with, and DeepSeek V4 Flash is the model most people reach for when the bill matters. Both are sparse, both hold a million tokens, and both are built for coding and long multi-step work.

The trade is narrow but clear. GLM 5.3 Flash has 320B parameters with 18B active per token, reads images and video, and costs $0.25 per million tokens. DeepSeek V4 Flash has 284B parameters with 13B active and costs $0.18, but it is text-only. Both offer tool use and zero data retention.

At a glance

Where GLM 5.3 Flash pulls ahead

• A complete default: GLM 5.3 Flash handles text, pictures and video, so you do not have to switch models when a screenshot arrives.
• Long agent runs that need to inspect visual output — rendered pages, charts, interface states — stay in one conversation.
• Slightly more active parameters per token, which can help on dense multi-step reasoning, though the difference is not a guarantee.

Where DeepSeek V4 Flash pulls ahead

• The lowest upstream price of the pair at $0.18 per million tokens, about 28% cheaper than GLM 5.3 Flash.
• Text-only coding and document work where vision would be unused overhead.
• Tighter active-parameter count (13B vs 18B) for high-volume text tasks where throughput and cost are the priority.

The price difference

GLM 5.3 Flash costs $0.25 per million tokens against $0.18 for DeepSeek V4 Flash — about 39% more. On UsingOpen you can chat with both for free inside the daily limit, so the rate is a fair proxy for how expensive each model is to run rather than a bill you pay here. Multiply it by your monthly token volume if you are comparing API access elsewhere.

Which should you choose?

For most people the default is the right answer: GLM 5.3 Flash sees images and video, handles long agent jobs, and the price gap is only seven cents per million tokens. If you are unsure, start there.

Choose DeepSeek V4 Flash when the work is purely text and code and you want the lowest rate on the page. It is also the better pick for a long-running text pipeline, where the 28% saving compounds and no one is pasting a picture.

Chat with GLM 5.3 Flash free · Chat with DeepSeek V4 Flash free

Frequently asked questions

Do GLM 5.3 Flash and DeepSeek V4 Flash have the same context window?

Yes — both are listed with a 1M context window, roughly 750,000 words. The practical limit is therefore similar, and the decision comes down to price, modalities and behaviour.

Which of GLM 5.3 Flash and DeepSeek V4 Flash can read images?

GLM 5.3 Flash accepts image input; DeepSeek V4 Flash is text-only. If a screenshot, diagram or video frame is part of the task, only GLM 5.3 Flash can handle it.

Is GLM 5.3 Flash or DeepSeek V4 Flash better for coding?

Both are tuned for coding or agent work: GLM 5.3 Flash for coding and long, multi-step work, DeepSeek V4 Flash for coding and agents. The faster way to choose is to send the same real task to both in Compare mode and read the answers; the spec sheet cannot settle it.

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

DeepSeek V4 Flash is listed at $0.18 per million tokens against $0.25 for GLM 5.3 Flash — about 28% cheaper. Both are free to chat with on UsingOpen inside the daily limit when live; the rates matter if you are comparing what API access would cost.

Can I chat with GLM 5.3 Flash and DeepSeek V4 Flash for free?

Yes. Both are selectable on UsingOpen without an account when they are live, and each user gets 10 free prompts per day. A model paused for capacity is unavailable until it returns; the picker shows live status. History stays on your device, and Compare mode can send one prompt to both models side by side.

Should I just use the default GLM 5.3 Flash?

Yes, unless your work is text-only and price-sensitive. The default is multimodal, holds a million tokens and costs $0.25 per million upstream tokens. DeepSeek V4 Flash saves about 28% but cannot read images, so the default is the safer first choice.

Which model is faster?

Both are mixture-of-experts models designed for speed: 18B of GLM 5.3 Flash's 320B is active per token, versus 13B of DeepSeek V4 Flash's 284B. Raw latency also depends on load and provider, so the honest answer is to run the same prompt through Compare mode on UsingOpen and judge for yourself.

Related comparisons

• DeepSeek V4 Flash vs Qwen3.8 Flash — The cheapest serious coder against Alibaba's fast multimodal all-rounder.
• GLM 5.3 vs GLM 5.3 Flash — Same family, opposite trade-offs: the full model is bigger; the Flash is multimodal.
• GPT-OSS 120B vs DeepSeek V4 Flash — OpenAI's open-weight reasoner against DeepSeek's long-context bargain.

All models · Compare models · Free AI chat · FAQ