OpenAI compatible API · Attested · Public status

Z.ai: GLM 5.1 vs GLM 5.2 Fast on Fireworks

Z.ai: GLM 5.1 vs GLM 5.2 Fast on Fireworks: 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 5.1 has the lower cheapest prompt+completion route on TrustedRouter. Z.ai: GLM 5.1 has more provider fallback routes, while GLM 5.2 Fast on Fireworks has the larger context window. Probe-backed speed data is shown when enough recent samples exist.

$4.2833/1MZ.ai: GLM 5.1 cheapest route

$9.1785/1MGLM 5.2 Fast on Fireworks cheapest route

2519 msZ.ai: GLM 5.1 fastest measured p50 TTFT via io-net

not enough dataGLM 5.2 Fast on Fireworks fastest measured p50 TTFT

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.

Z.ai: GLM 5.1GLM 5.2 Fast on Fireworks

Model idz-ai/glm-5.1z-ai/glm-5.2-fast

Publisher Z.AI Z.AI

AI IQ IQ 114#42 —

Context200,000 tokens1,048,576 tokens

Credits provider routes152

Cheapest route$4.2833/1M$9.1785/1M

Cached input$0.10339/1M to $0.680475/1M$0.22155/1M

Privacy posturehas provider E2EE routehas ZDR route

Fastest measured p50 TTFT2519 ms via io-netnot enough data

Highest measured throughputnot enough data85 tok/s via fireworks

Recent route uptime range0.00% to 100.00%100.00%

Modes chat chat

Z.ai: GLM 5.1 routes

Overview15 Credits routes
PricingInput, cached input, and output rates
BenchmarksTrustedRouter and external sources
ProvidersAll serving providers

GLM 5.2 Fast on Fireworks routes

Overview2 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="z-ai/glm-5.1",
    messages=messages,
)

Questions

Which should I use, Z.ai: GLM 5.1 or GLM 5.2 Fast on Fireworks?

Is Z.ai: GLM 5.1 or GLM 5.2 Fast on Fireworks cheaper?

The current cheapest TrustedRouter route is $4.2833/1M for Z.ai: GLM 5.1 and $9.1785/1M for GLM 5.2 Fast on Fireworks. The comparison uses current catalog prices and updates as provider pricing changes.

Is Z.ai: GLM 5.1 or GLM 5.2 Fast on Fireworks faster?

Current measured p50 time to first token is 2519 ms for Z.ai: GLM 5.1 and not enough data for GLM 5.2 Fast on Fireworks. These are routed probe measurements, not vendor-advertised speeds, and update as new samples arrive.

Can I test Z.ai: GLM 5.1 and GLM 5.2 Fast on Fireworks 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-5.1 and z-ai/glm-5.2-fast. This makes side-by-side evals possible without maintaining two provider integrations.