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Z.ai · GLM · Fast

GLM 5.3 Flash

Discount −58%New

Z.ai's fast, low-cost GLM model for quick answers, drafting and simple tool calls.

Model id

glm-5.3-flash
Get an API keyTry in Chat

Price per 1M tokens

Input
Regular rate $0.15now $0.07
Output
Regular rate $0.50now $0.21
Cached input
$0.0357% below input

58% below the market rate.

Added here 18 Oct 2026 — read the changelog for what changed and why.

Output is 3× the input rate. $1 covers about 5,681 prompts of 1,000 input + 500 output tokens. 1 credit = $1 of usage. All rates

Start using GLM 5.3 Flash

Set ONEAIAPIKEY_API_KEY to a key from your console, then run any example. Streaming is on so long answers are not cut off by idle-connection timeouts.

curl https://api.oneaiapikey.com/v1/chat/completions \
  -H "Authorization: Bearer $ONEAIAPIKEY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "glm-5.3-flash",
    "stream": true,
    "messages": [{"role": "user", "content": "What does HTTP status 409 mean, in one sentence?"}]
  }'
import os
from openai import OpenAI

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

stream = client.chat.completions.create(
    model="glm-5.3-flash",
    messages=[{"role": "user", "content": "What does HTTP status 409 mean, in one sentence?"}],
    stream=True,  # recommended for long outputs
)
for chunk in stream:
    if chunk.choices and chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="", flush=True)
import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.oneaiapikey.com/v1",
  apiKey: process.env.ONEAIAPIKEY_API_KEY,
});

const stream = await client.chat.completions.create({
  model: "glm-5.3-flash",
  messages: [{ role: "user", content: "What does HTTP status 409 mean, in one sentence?" }],
  stream: true,
});

for await (const chunk of stream) {
  process.stdout.write(chunk.choices[0]?.delta?.content ?? "");
}

More: quickstart · API reference · try it in Chat first

Benchmarks reported by the vendor

Scores for GLM 5.3 Flash as its maker published them, with the setting they state. We have not re-run them. Versions and settings differ between vendors, so compare only identical benchmark names; compare models side by side.

Tokens per day, by model

Last 7 days, UTC days

Hover, tap or drag across any day, or focus the chart and use the arrow keys, to see how every model did that day.

Real tokens served through this gateway, updated every 5 minutes. Ranked by usage, not quality.

Full ranking insights

GLM line-up

GLM 5.3 Flash or GLM 5.3 or Claude Haiku 5.5?

Of the 2 GLM models on this site, GLM 5.3 is the step up from GLM 5.3 Flash, and nothing in the family sits below it. Claude Haiku 5.5 from Anthropic is the closest-priced fast-tier model from another vendor. Each comparison lists the published rates and limits, then what favours each side.

GLM 5.3 FlashvsGLM 5.3

Per 1M tokensGLM 5.3 FlashGLM 5.3
Input$0.0782% less$0.396
Output$0.2173% less$0.77
Cached input$0.0388% less$0.26

Pick GLM 5.3 Flash when

  • cost per request decides it: GLM 5.3 Flash charges input 82% less and output 73% less than GLM 5.3.
  • the work is quick answers, drafting and sub-agents, which this catalogue lists for GLM 5.3 Flash and not for GLM 5.3.

Pick GLM 5.3 instead when

  • GLM 5.3 Flash falls short and you want the balanced model of the pair.
  • GLM 5.3 Flash does not list Reasoning and your code depends on it.
  • your workload looks like coding help, writing and translation, labels the catalogue gives GLM 5.3 only.

GLM 5.3 FlashvsClaude Haiku 5.5

Per 1M tokensGLM 5.3 FlashClaude Haiku 5.5
Input$0.07the same$0.07
Output$0.2140% less$0.35
Cached input$0.033× as much$0.01

Pick GLM 5.3 Flash when

  • cost per request decides it: GLM 5.3 Flash charges output 40% less than Claude Haiku 5.5.
  • you rely on JSON mode, which Claude Haiku 5.5 does not list.
  • the work is quick answers and drafting, which this catalogue lists for GLM 5.3 Flash and not for Claude Haiku 5.5.

Pick Claude Haiku 5.5 instead when

  • GLM 5.3 Flash does not list Vision, Reasoning and Structured output and your code depends on it.
  • you send images, which only Claude Haiku 5.5 of the two accepts.
  • your workload looks like classification and support chat, labels the catalogue gives Claude Haiku 5.5 only.

Use cases

What GLM 5.3 Flash is listed for, and what it costs

The catalogue lists GLM 5.3 Flash for quick answers, drafting and sub-agents. Each row prices one typical request at the published rates, with the arithmetic shown. The market-rate figure shows the same request at the lowest public price elsewhere. Token counts are examples; your prompts will differ.

Model your own traffic

  1. Quick answers

    A short question and a short answer: 300 tokens in, 250 tokens out.

    “What does HTTP status 409 mean, in one sentence?”

    Same request on GLM 5.3 $0.000312 and Claude Haiku 5.5 $0.000108.

    $0.000074

    per answer, about 135,135 per $10

    $0.00017 at the market rate

    0.0003 × $0.07 + 0.00025 × $0.21

  2. Drafting

    A brief plus source notes: 3,000 tokens in, a draft of roughly 1,200 words (1,600 tokens) out.

    Good for first drafts you will edit; ask for a specific length and tone.

    “Turn these release notes into a 300-word changelog post for developers.”

    Same request on GLM 5.3 $0.00242 and Claude Haiku 5.5 $0.00077.

    $0.000546

    per draft, about 18,315 per $10

    $0.00125 at the market rate

    0.003 × $0.07 + 0.0016 × $0.21

  3. Sub-agents

    A helper step for a larger model: 6,000 tokens of file or search results in, a 500-token summary out.

    Route search, summarising and file triage here while a larger model leads.

    “List every function in this file that writes to the database, one per line.”

    Same request on GLM 5.3 $0.00276 and Claude Haiku 5.5 $0.000596.

    $0.000526

    per helper call, about 19,011 per $10

    $0.00115 at the market rate

    0.006 × $0.07 + 0.0005 × $0.21

Overview

When GLM 5.3 Flash fits

GLM 5.3 Flash is a fast, low-cost model from Z.ai, available here under the exact model id “glm-5.3-flash”. It is the entry point of the GLM line-up here, below GLM 5.3. Z.ai has not published a release date we can cite; it has been available here since 18 Oct 2026.

Z.ai documents tools, json mode and prompt caching for it.

It costs $0.07 per million input tokens and $0.21 per million output tokens, so output is 3× the input rate. That is 58% below the market rate of $0.15 input and $0.50 output per million tokens, the lowest public price we found at other API gateways. On the use cases below, output makes up 71% of the bill for quick answers, 62% for drafting and 20% for sub-agents, so capping max tokens and asking for diffs saves more than trimming the prompt. With a 3:1 input-to-output mix it ranks 4th lowest-cost of the 27 models on this site.

Cached input bills at $0.03 per million tokens, 57% below the standard input rate, which pays off when the same system prompt or documents go out on every request.

It is served through the OpenAI-compatible format at https://api.oneaiapikey.com/v1, so any SDK or tool that lets you set a custom base URL, for example Codex CLI, Cursor and Cline, can use it. It is not offered on the Anthropic Messages endpoint; pick an Anthropic-format model for Claude Code.

Similar models

Same tier, other vendors

Same key, same balance. Switching is a change to the model field.

Compare side by sideAll models

Use GLM 5.3 Flash with any balance.

GLM 5.3 Flash is a paid model: any balance above $0 pays for it, the $10.00 sign-up credit included. When it runs out, add $1 or more to your wallet. Every request is billed at the rates above, with a receipt in your usage log.

Create an accountSee pricing

GLM 5.3 Flash is developed by Z.ai. Model names and trademarks belong to their owners. One AI API Key is an independent API gateway and is not affiliated with, endorsed by or sponsored by Z.ai.