OpenAI compatible API · Attested · Public status

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

GPT-5 Mini 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 cheapest prompt+completion route on TrustedRouter. Z.ai: GLM 5.3 Flash has more provider fallback routes, while Z.ai: GLM 5.3 Flash has the larger context window. Current TrustedRouter probes show Z.ai: GLM 5.3 Flash with the lower p50 TTFT.

$2.37375/1MOpenAI: GPT-5 Mini cheapest route

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

2153 msOpenAI: GPT-5 Mini fastest measured p50 TTFT via openai

1284 msZ.ai: GLM 5.3 Flash fastest measured p50 TTFT via friendli

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 MiniZ.ai: GLM 5.3 Flash

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

Publisher OpenAI Z.AI

AI IQ — IQ 121#24

Context400,000 tokens1,048,576 tokens

Credits provider routes220

Cheapest route$2.37375/1M$0.32705/1M

Cached input$0.026375/1M$0.015825/1M to $0.1055/1M

Privacy posturehas ZDR routehas provider E2EE route

Fastest measured p50 TTFT2153 ms via openai1284 ms via friendli

Highest measured throughputnot enough datanot enough data

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

Modes chat chat

OpenAI: GPT-5 Mini routes

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

Z.ai: GLM 5.3 Flash routes

Overview20 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-mini",
    messages=messages,
)

Questions

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

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

The current cheapest TrustedRouter route is $2.37375/1M for OpenAI: GPT-5 Mini 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 Mini or Z.ai: GLM 5.3 Flash faster?

Current measured p50 time to first token is 2153 ms for OpenAI: GPT-5 Mini and 1284 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 Mini 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-mini and z-ai/glm-5.3-flash. This makes side-by-side evals possible without maintaining two provider integrations.