After a stunning debut last week with cyber capabilities so advanced they reportedly found a previously undetected vulnerability in Cursor, GLM-5.3, the new frontier open source language model from Chinese startup z.ai, has now hit the application programming interface (API) — allowing developers the ability to build atop it and plug it into their agents and applications.
Developers who previously subscribed to a GLM Coding Plan are currently limited to the OpenAI Chat Completions-compatible protocol. Z.ai said it plans to make the model's weights openly available, but a precise date and licensing remain to be seen.
On the API, the price is unchanged from GLM-5.2: $1.40 per million input tokens and $4.40 per million output tokens. Cached input costs $0.26 per million tokens, while Z.ai currently lists cached-input storage as free for a limited time.
That means developers can move to the new generation without taking a higher posted per-token rate from Z.ai, even as the company claims substantially stronger coding and long-horizon agent performance.
At those rates, GLM-5.3 sits well below several of the highest-end frontier APIs.
Model
Input ($/1M)
Output ($/1M)
Total ($/1M)
Source
Muse Spark 1.2 Contributor
$0.10
$0.20
$0.30
Meta
MiMo-V2.5 Flash
$0.10
$0.30
$0.40
Xiaomi
DeepSeek-V4-Flash — off-peak
$0.22
$0.66
$0.88
DeepSeek
GPT-5.6 Luna
$0.20
$1.20
$1.40
OpenAI
MiniMax-M3
$0.30
$1.20
$1.50
MiniMax
LongCat-2.0 — limited-time promo
$0.30
$1.20
$1.50
LongCat
DeepSeek-V4-Flash — peak hours
$0.44
$1.32
$1.76
DeepSeek
MiMo-V2.5
$0.40
$2.00
$2.40
Xiaomi
DeepSeek-V4-Pro — off-peak
$0.66
$1.98
$2.64
DeepSeek
LongCat-2.0 — standard
$0.75
$2.95
$3.70
LongCat
MiMo-V2.5 Pro (≤256K)
$1.00
$3.00
$4.00
Xiaomi
Gemini 3.6 Flash — through Dec. 31, 2026
$0.75
$3.75
$4.50
Gemini 3.7 Flash — through Dec. 31, 2026
$0.75
$3.75
$4.50
DeepSeek-V4-Pro — peak hours
$1.32
$3.96
$5.28
DeepSeek
Muse Spark 1.1 / 1.2
$1.25
$4.25
$5.50
Meta
GLM-5.3
$1.40
$4.40
$5.80
Z.AI
Grok 4.6 — <200K prompt tokens
$2.00
$6.00
$8.00
xAI
MiMo-V2.5 Pro (>256K)
$2.00
$6.00
$8.00
Xiaomi
Qwen3.8-Max
$2.00
$6.00
$8.00
QwenCloud
Gemini 3.6 Flash — starting Jan. 1, 2027
$1.50
$7.50
$9.00
Gemini 3.7 Flash — starting Jan. 1, 2027
$1.50
$7.50
$9.00
GPT-5.6 Terra
$2.00
$12.00
$14.00
OpenAI
Grok 4.6 — ≥200K prompt tokens
$4.00
$12.00
$16.00
xAI
GPT-5.4
$2.50
$15.00
$17.50
OpenAI
Kimi K3
$3.00
$15.00
$18.00
Moonshot AI
Claude Opus 5
$5.00
$25.00
$30.00
Anthropic
Sakana Fugu Ultra (≤272K)
$5.00
$30.00
$35.00
Sakana AI
GPT-5.6 Sol — Standard mode
$5.00
$30.00
$35.00
OpenAI
Claude Fable 5 / Claude Mythos 5
$10.00
$50.00
$60.00
Anthropic
GPT-5.6 Sol — Fast mode
$10.00
$60.00
$70.00
OpenAI
Using the simple VentureBeat comparison of one million input tokens plus one million output tokens, GLM-5.3 comes to $5.80, versus $8 for Grok 4.6 at its lower context rate, $18 for Kimi K3, $30 for Claude Opus 5 and $35 for GPT-5.6 Sol.
That is not a workload-cost estimate — real bills depend heavily on the input/output mix, caching and token consumption — but it makes the relative API price tier easy to see.
GLM-5.3 is not the cheapest capable model available. Google’s current introductory price for Gemini 3.7 Flash is $0.75 per million input tokens and $3.75 per million output tokens through Dec. 31, 2026, while OpenAI’s GPT-5.6 Luna is priced at $0.20 input and $1.20 output.
Still, Z.ai’s price puts GLM-5.3 into a notably lower cost band than the premium frontier models it is increasingly benchmarked against.
That comparison has become more relevant following the latest independent results. Artificial Analysis gives GLM-5.3 a score of 60 on its Intelligence Index, tying Kimi K3 as the top performing open weights model in the world, and scoring seven points higher than GLM-5.2. I
ts analysis also estimates GLM-5.3 at about $0.68 per Intelligence Index task, versus roughly $0.44 for GLM-5.2, despite the identical API token prices.
The difference underscores an important caveat in headline API pricing: Artificial Analysis found GLM-5.3 more verbose than its predecessor, so flat per-token rates do not necessarily mean flat costs for a completed workload.
For developers, though, the immediate change is straightforward: GLM-5.3 is now callable through Z.ai’s API at the same $1.40/$4.40 per-million-token rate as GLM-5.2, giving teams another relatively low-cost option for testing frontier-class coding and agent workloads.
