GLM-5.3

GLM-5.3 is Z.AI's flagship reasoning model, built for complex software engineering, long-horizon agent tasks, and security work such as vulnerability discovery.

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input · usd / 1m tok

$1.40

output · usd / 1m tok

$4.40

context window

1mtokens

modalities · in → out

takes text in, gives text out

pricing

base api ratesusd per 1m tokens

input
$1.40
output
$4.40
cache read
$0.26

providers

Different companies host GLM-5.3. Impossibl routes your request intelligently and handles failover automatically when a provider is down.

  • Azure AI Foundry
  • Z.AI
  • Fireworks

specifications

takes text in, gives text outzai/glm-5.3

  • creatorZ.AI
  • model typeText generation
  • context window1,000,000 tokens
  • maximum outputnot published
  • input

    takes text in, gives text out

  • outputtext
  • tool callingnot verified
  • releasedaug 14, 2026
  • endpoint/v1/chat/completions

unknown means the public catalog does not establish that fact. a model's documented capabilities can differ from what a particular api supports. see the model documentation for integration details.

try it · your prompt, this model, live

# responses API
import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["IMPOSSIBL_API_KEY"],
    base_url="https://api.impossibl.com/v1",
)

resp = client.responses.create(
    model="zai/glm-5.3",
    input="",
)
print(resp.output_text)

edit the prompt, then run

benchmarks

intelligence index

31.7#15 of 35 models on the gateway

  1. coding index74.8#14 of 59
  2. agentic index53.1#5 of 52
  • Intelligence Index31.65
  • legal index (API)42
  • coding index (API)74.8
  • agentic index (API)53.1
  • economics index (API)51.2
  • engineering index (API)47.1
  • intelligence index (API)44.8
  • strategy and ops index (API)47.6
  • finance and accounting index (API)44.7
  • healthcare and medical index (API)46.7

view source ↗all source data and breakdowns (json) ↗

each configuration is listed separately; these evaluations describe the tested model configuration, and performance and costs can differ on impossibl. unmeasured scores are omitted and api values keep their source units. last checked 2026-11-03. some source data could not be refreshed; retained results may be older.

compare GLM-5.3 with other models

frontier labs and open weights, best-ranked firstusd / 1m tok · in / out

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frequently asked questions

What is GLM-5.3?

GLM-5.3 is Z.AI's flagship reasoning model, built for complex software engineering, long-horizon agent tasks, and security work such as vulnerability discovery. It succeeds GLM-5.2 with a large gain on Z.AI's own coding bench and supports long text inputs with tool calling.

How much does GLM-5.3 cost?

GLM-5.3 costs $1.40 per million input tokens and $4.40 per million output tokens through the Impossibl API. Cache reads cost $0.26 per million tokens. All rates are in USD.

view the pricing table ↑

What is the context length of GLM-5.3?

GLM-5.3 has a 1,000,000-token context window through the Impossibl API.

What inputs and outputs does GLM-5.3 support?

GLM-5.3 accepts text as input. GLM-5.3 returns text.

How do I use GLM-5.3 through an API?

GLM-5.3 is available through the Impossibl API. Use zai/glm-5.3 as the model identifier with /v1/chat/completions. The quickstart explains how to create an API key and send your first request.

follow the api quickstart →

When was GLM-5.3 released?

Z.AI released GLM-5.3 on August 14, 2026.

this page describes GLM-5.3 as listed by the impossibl public api. prices and availability come from that catalog, refreshed here every five minutes. this is an impossibl offering, not a comparison of independent hosting-provider quotes. model descriptions and release dates, where available, use the creator sources linked under the answers above.

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