GLM 5.3 Flash vs GLM 5.3 FlashX

Practical read: GLM 5.3 Flash costs about a sixth as much and starts answering sooner. One API key runs both.

No card required. Start with 1 million free tokens.

Side by side:

Z.ai: GLM 5.3 Flash compared with Z.ai: GLM 5.3 FlashX
Attribute	GLM 5.3 Flash `z-ai/glm-5.3-flash`	GLM 5.3 FlashX `z-ai/glm-5.3-flashx`
Price, 1M in + out	$0.26 Wafer, cheapest route	$1.71 Novita AI, cheapest route
Best for	Low cost and speed
Input / output, 1M	$0.053 / $0.21	$0.39 / $1.32
Cached input	$0.015825/1M to $0.079125/1M	$0.079125/1M
Context window	1.05M 1,048,576 tokens	1.05M 1,048,576 tokens
First token, p50	0.72 s via FriendliAI	2.4 s via Tencent Cloud TokenHub
AI IQ	IQ 119 #50 on AI IQ	Unrated
Provider routes	32 with failover	3 with failover
Privacy	Confidential E2EE and zero retention route	Varies by provider
Recent route uptime range	0.00% to 100.00%	100.00%
Publisher	Z.AI	Z.AI
Modes	chat	chat
More detail	Overview Pricing Providers	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 GLM 5.3 Flash and GLM 5.3 FlashX 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 z-ai/glm-5.3-flash, then on z-ai/glm-5.3-flashx.
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 ("z-ai/glm-5.3-flash", "z-ai/glm-5.3-flashx"):
    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 z-ai/glm-5.3-flash z-ai/glm-5.3-flashx; 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, Z.ai: GLM 5.3 Flash or Z.ai: GLM 5.3 FlashX?

Z.ai: GLM 5.3 Flash has the lower published input-plus-output rate, more Credits provider routes and the lower measured p50 time to first token. Their context windows are the same size.

Is Z.ai: GLM 5.3 Flash or Z.ai: GLM 5.3 FlashX cheaper?

The current cheapest TrustedRouter route is $0.26375/1M for Z.ai: GLM 5.3 Flash and $1.7091/1M for Z.ai: GLM 5.3 FlashX. The comparison uses current catalog prices and updates as provider pricing changes.

Is Z.ai: GLM 5.3 Flash or Z.ai: GLM 5.3 FlashX faster?

Current measured p50 time to first token is 719 ms for Z.ai: GLM 5.3 Flash and 2377 ms for Z.ai: GLM 5.3 FlashX. These are routed probe measurements, not vendor-advertised speeds, and update as new samples arrive.

Can I test Z.ai: GLM 5.3 Flash and Z.ai: GLM 5.3 FlashX with the same API?

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

More comparisons

All comparisons

Try GLM 5.3 Flash and GLM 5.3 FlashX 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.