GLM-5.3 hits the API at $1.4/$4.4 per million tokens

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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 Google Gemini 3.7 Flash — through Dec. 31, 2026 $0.75 $3.75 $4.50 Google 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 — 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 Google Gemini 3.7 Flash — starting Jan. 1, 2027 $1.50 $7.50 $9.00 Google 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 consumptio…