DeepSeek V4.1 Flash 1017 Ultrafast vs GLM 5.3 Flash

Practical read: GLM 5.3 Flash costs under a tenth as much. One API key runs both.

No card required. Start with 1 million free tokens.

Side by side:

DeepSeek V4.1 Flash 1017 Ultrafast compared with Z.ai: GLM 5.3 Flash
Attribute	DeepSeek V4.1 Flash 1017 Ultrafast `deepseek/deepseek-v4-1-flash-1017-ultrafast`	GLM 5.3 Flash `z-ai/glm-5.3-flash`
Price, 1M in + out	$15.82 Venice, cheapest route	$0.26 Wafer, cheapest route
Best for		Low cost
Input / output, 1M	$3.16 / $12.66	$0.053 / $0.21
Cached input	$0.0633/1M	$0.015825/1M to $0.079125/1M
Context window	1M 1,000,000 tokens	1.05M 1,048,576 tokens
First token, p50	Measuring	0.72 s via FriendliAI
AI IQ	Unrated	IQ 119 #50 on AI IQ
Provider routes	1	32 with failover
Privacy	Varies by provider	Confidential E2EE and zero retention route
Recent route uptime range	not enough data	0.00% to 100.00%
Publisher	DeepSeek	Z.AI
Modes	chat	chat
More detail	Overview	Overview Pricing Providers

Price adds one million input and one million output tokens on the cheapest route. Prices and speed change: see the monthly reports and run a small eval before you choose a default.

Test both with your agent

Paste this into Claude Code, Cursor or any coding agent.

Compare DeepSeek V4.1 Flash 1017 Ultrafast and GLM 5.3 Flash in this project through TrustedRouter.

1. Read https://trustedrouter.com/docs/llms.txt
2. Point the OpenAI-compatible client at
   https://api.trustedrouter.com/v1 and read the key from
   TRUSTEDROUTER_API_KEY.
3. Run our eval prompts on deepseek/deepseek-v4-1-flash-1017-ultrafast, then on z-ai/glm-5.3-flash.
4. Show me cost, latency and quality side by side before changing the default.

import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.trustedrouter.com/v1",
    api_key=os.environ["TRUSTEDROUTER_API_KEY"],
)
for model in ("deepseek/deepseek-v4-1-flash-1017-ultrafast", "z-ai/glm-5.3-flash"):
    response = client.chat.completions.create(
        model=model,
        messages=[{"role": "user", "content": "What is the capital of France?"}],
    )
    print(model, response.choices[0].message.content)

for model in deepseek/deepseek-v4-1-flash-1017-ultrafast z-ai/glm-5.3-flash; do
  curl https://api.trustedrouter.com/v1/chat/completions \
    -H "Authorization: Bearer $TRUSTEDROUTER_API_KEY" \
    -H "Content-Type: application/json" \
    -d "{\"model\": \"$model\", \"messages\": [{\"role\": \"user\", \"content\": \"What is the capital of France?\"}]}"
done

Your agent will need an API key.

Questions

Which should I use, DeepSeek V4.1 Flash 1017 Ultrafast or Z.ai: GLM 5.3 Flash?

Z.ai: GLM 5.3 Flash has the lower published input-plus-output rate, more Credits provider routes and the larger context window. There is not enough recent probe data to compare speed.

Is DeepSeek V4.1 Flash 1017 Ultrafast or Z.ai: GLM 5.3 Flash cheaper?

The current cheapest TrustedRouter route is $15.825/1M for DeepSeek V4.1 Flash 1017 Ultrafast and $0.26375/1M for Z.ai: GLM 5.3 Flash. The comparison uses current catalog prices and updates as provider pricing changes.

Is DeepSeek V4.1 Flash 1017 Ultrafast or Z.ai: GLM 5.3 Flash faster?

Current measured p50 time to first token is not enough data for DeepSeek V4.1 Flash 1017 Ultrafast and 719 ms for Z.ai: GLM 5.3 Flash. These are routed probe measurements, not vendor-advertised speeds, and update as new samples arrive.

Can I test DeepSeek V4.1 Flash 1017 Ultrafast and Z.ai: GLM 5.3 Flash with the same API?

Yes. Use the same OpenAI-compatible TrustedRouter base URL and API key, then change only the model id between deepseek/deepseek-v4-1-flash-1017-ultrafast and z-ai/glm-5.3-flash. This makes side-by-side evals possible without maintaining two provider integrations.

More comparisons

All comparisons

Try DeepSeek V4.1 Flash 1017 Ultrafast and GLM 5.3 Flash with one key.

TrustedRouter is useful when you know the model you want, but still need provider rollover, budget limits, usage records, and a prompt path you can verify.

No card required. Start with 1 million free tokens.