OpenAI compatible API · Attested · Public status

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

GPT-5 Nano vs Z.ai: GLM 5.3 Flash: compare current API pricing, context, provider routes, privacy, p50 latency, and OpenAI-compatible access.

Verify gateway

Onebase URL to migrate

100sof models and routes

0prompt or output logs. Always.

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 Flash has the lower published input-plus-output rate, more Credits provider routes, the larger context window and the lower measured p50 time to first token.

$0.47475/1MOpenAI: GPT-5 Nano cheapest route

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

3845 msOpenAI: GPT-5 Nano fastest measured p50 TTFT via lightning

680 msZ.ai: GLM 5.3 Flash fastest measured p50 TTFT via fireworks

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 NanoZ.ai: GLM 5.3 Flash

Model idopenai/gpt-5-nanoz-ai/glm-5.3-flash

Publisher OpenAI Z.AI

AI IQ IQ 93#112 IQ 116#39

Context400,000 tokens1,048,576 tokens

Credits provider routes225

Cheapest route$0.47475/1M$0.32705/1M

Cached input$0.01/1M$0.015825/1M to $0.110775/1M

Privacy posturehas ZDR routehas provider E2EE route

Fastest measured p50 TTFT3845 ms via lightning680 ms via fireworks

Highest measured throughputnot enough datanot enough data

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

Modes chat chat

OpenAI: GPT-5 Nano routes

Overview2 Credits routes
PricingInput, cached input, and output rates
ProvidersAll serving providers

Z.ai: GLM 5.3 Flash routes

Overview25 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-nano",
    messages=messages,
)

Questions

Which should I use, OpenAI: GPT-5 Nano 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, the larger context window and the lower measured p50 time to first token.

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

The current cheapest TrustedRouter route is $0.47475/1M for OpenAI: GPT-5 Nano 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 Nano or Z.ai: GLM 5.3 Flash faster?

Current measured p50 time to first token is 3845 ms for OpenAI: GPT-5 Nano and 680 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 Nano 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-nano and z-ai/glm-5.3-flash. This makes side-by-side evals possible without maintaining two provider integrations.