DeepSeek V4.1 Flash vs GLM 5.3 Flash (Fortanix)
Practical read: DeepSeek V4.1 Flash reads eight times more context and starts answering sooner. GLM 5.3 Flash (Fortanix) costs about an eighth as much. One API key runs both.
No card required. Start with 1 million free tokens.
Side by side:
| Attribute | DeepSeek V4.1 Flash | GLM 5.3 Flash (Fortanix) |
|---|---|---|
| Price, 1M in + out | $0.16 Engy, cheapest route | $0.02 Fortanix, cheapest route |
| Best for | Long documents and speed | Low cost |
| Input / output, 1M | $0.032 / $0.13 | $0.01 / $0.01 |
| Cached input | $0.01/1M to $0.165108/1M | Not published |
| Context window | 1.05M 1,048,576 tokens | 131K 131,072 tokens |
| First token, p50 | 0.68 s via Wafer | 1.4 s via Fortanix |
| AI IQ | IQ 126 #24 on AI IQ | IQ 119 #50 on AI IQ |
| Provider routes | 21 with failover | 1 |
| Privacy | Confidential E2EE and zero retention route | Zero retention route |
| Recent route uptime range | 96.87% to 100.00% | 91.67% |
| Publisher | DeepSeek | fortanix |
| Modes | chat decide | chat |
| More detail |
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 and GLM 5.3 Flash (Fortanix) 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, then on fortanix/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", "fortanix/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 fortanix/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?\"}]}"
doneQuestions
Which should I use, DeepSeek: DeepSeek V4.1 Flash or GLM 5.3 Flash (Fortanix)?
DeepSeek V4.1 Flash has more Credits provider routes, the larger context window and the lower measured p50 time to first token. GLM 5.3 Flash (Fortanix) has the lower published input-plus-output rate.
Is DeepSeek: DeepSeek V4.1 Flash or GLM 5.3 Flash (Fortanix) cheaper?
The current cheapest TrustedRouter route is $0.15825/1M for DeepSeek: DeepSeek V4.1 Flash and $0.02/1M for GLM 5.3 Flash (Fortanix). The comparison uses current catalog prices and updates as provider pricing changes.
Is DeepSeek: DeepSeek V4.1 Flash or GLM 5.3 Flash (Fortanix) faster?
Current measured p50 time to first token is 681 ms for DeepSeek: DeepSeek V4.1 Flash and 1376 ms for GLM 5.3 Flash (Fortanix). These are routed probe measurements, not vendor-advertised speeds, and update as new samples arrive.
Can I test DeepSeek: DeepSeek V4.1 Flash and GLM 5.3 Flash (Fortanix) 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 and fortanix/glm-5.3-flash. This makes side-by-side evals possible without maintaining two provider integrations.
More comparisons
All comparisonsTry DeepSeek V4.1 Flash and GLM 5.3 Flash (Fortanix) 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.