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OpenAI: GPT-5.6 Luna vs Z.ai: GLM 5.3 Flash

Try both on us. Starter credit covers your first requests, then one key routes GPT-5.6 Luna and GLM 5.3 Flash. 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

GPT-5.6 Luna has the larger context window. Z.ai: GLM 5.3 Flash has the lower published input-plus-output rate and more Credits provider routes. There is not enough recent probe data to compare speed.

$1.477/1MOpenAI: GPT-5.6 Luna cheapest route

$0.32705/1MZ.ai: GLM 5.3 Flash cheapest route

not enough dataOpenAI: GPT-5.6 Luna fastest measured p50 TTFT

989 msZ.ai: GLM 5.3 Flash fastest measured p50 TTFT via baseten

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-5.6 LunaZ.ai: GLM 5.3 Flash

Model idopenai/gpt-5.6-lunaz-ai/glm-5.3-flash

Publisher OpenAI Z.AI

AI IQ IQ 124#29 IQ 119#45

Context1,050,000 tokens1,048,576 tokens

Credits provider routes332

Cheapest route$1.477/1M$0.32705/1M

Cached input$0.0211/1M$0.015825/1M to $0.068575/1M

Privacy posturehas ZDR routehas Confidential route (E2EE + ZDR)

Fastest measured p50 TTFTnot enough data989 ms via baseten

Highest measured throughputnot enough datanot enough data

Recent route uptime range100.00%0.00% to 100.00%

Modes chat chat

OpenAI: GPT-5.6 Luna routes

Overview3 Credits routes
PricingInput, cached input, and output rates
ProvidersAll serving providers

Z.ai: GLM 5.3 Flash routes

Overview32 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-5.6-luna",
    messages=messages,
)

Questions

Which should I use, OpenAI: GPT-5.6 Luna or Z.ai: GLM 5.3 Flash?

Is OpenAI: GPT-5.6 Luna or Z.ai: GLM 5.3 Flash cheaper?

The current cheapest TrustedRouter route is $1.477/1M for OpenAI: GPT-5.6 Luna and $0.32705/1M for Z.ai: GLM 5.3 Flash. The comparison uses current catalog prices and updates as provider pricing changes.

Is OpenAI: GPT-5.6 Luna or Z.ai: GLM 5.3 Flash faster?

Current measured p50 time to first token is not enough data for OpenAI: GPT-5.6 Luna and 989 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 OpenAI: GPT-5.6 Luna 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 openai/gpt-5.6-luna and z-ai/glm-5.3-flash. This makes side-by-side evals possible without maintaining two provider integrations.