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OpenAI: GPT-5 vs Z.ai: GLM 5.3

Try both on us. Starter credit covers your first requests, then one key routes GPT-5 and GLM 5.3. Switch by changing the model name.

Compare routesProviders, price, context, and policy posture in one view.

Use auto when uptime mattersKeep a primary model and let fallback handle provider failures.

Same API shapeUse the OpenAI client and set the model you want.

Practical read

Monthly evidence

Z.ai: GLM 5.3 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.

$11.86875/1MOpenAI: GPT-5 cheapest route

$3.458818/1MZ.ai: GLM 5.3 cheapest route

not enough dataOpenAI: GPT-5 fastest measured p50 TTFT

1068 msZ.ai: GLM 5.3 fastest measured p50 TTFT via thinkingmachines

The price comparison adds each route's rate for one million input tokens and one million output tokens; your cost depends on your input/output mix. Prices and live route measurements can change. Use the monthly reports when you need a stable evidence window, then run a small task-specific eval before choosing a production default.

OpenAI: GPT-5Z.ai: GLM 5.3

Model idopenai/gpt-5z-ai/glm-5.3

Publisher OpenAI Z.AI

AI IQ IQ 111#69 IQ 124#28

Context400,000 tokens1,048,576 tokens

Credits provider routes133

Cheapest route$11.86875/1M$3.458818/1M

Cached input$0.131875/1M$0.1055/1M to $0.84189/1M

Privacy posturehas ZDR routehas Confidential route (E2EE + ZDR)

Fastest measured p50 TTFTnot enough data1068 ms via thinkingmachines

Highest measured throughputnot enough data196 tok/s via thinkingmachines

Recent route uptime range100.00%85.71% to 100.00%

Modes chat chat

OpenAI: GPT-5 routes

Overview1 Credits routes

Z.ai: GLM 5.3 routes

Overview33 Credits routes
PricingInput, cached input, and output rates
ProvidersAll serving providers

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Production choice

Pick a default model. Keep fallback enabled.

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.

OpenAI clientPython

client = OpenAI(
    base_url="https://api.trustedrouter.com/v1",
    api_key="sk-tr-v1-..."
)

response = client.chat.completions.create(
    model="openai/gpt-5",
    messages=messages,
)

Questions

Which should I use, OpenAI: GPT-5 or Z.ai: GLM 5.3?

Z.ai: GLM 5.3 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 OpenAI: GPT-5 or Z.ai: GLM 5.3 cheaper?

The current cheapest TrustedRouter route is $11.86875/1M for OpenAI: GPT-5 and $3.458818/1M for Z.ai: GLM 5.3. The comparison uses current catalog prices and updates as provider pricing changes.

Is OpenAI: GPT-5 or Z.ai: GLM 5.3 faster?

Current measured p50 time to first token is not enough data for OpenAI: GPT-5 and 1068 ms for Z.ai: GLM 5.3. These are routed probe measurements, not vendor-advertised speeds, and update as new samples arrive.

Can I test OpenAI: GPT-5 and Z.ai: GLM 5.3 with the same API?

Yes. Use the same OpenAI-compatible TrustedRouter base URL and API key, then change only the model id between openai/gpt-5 and z-ai/glm-5.3. This makes side-by-side evals possible without maintaining two provider integrations.