GLM 5.3 on QuickSilver Pro
GLM 5.3 is Z.ai's newest reasoning flagship, tuned for complex software engineering and long-horizon agent tasks, with a 1M-token context window and 131K max output. On QuickSilver Pro it is $0.60 input / $2.20 output per million tokens, at parity with the OpenRouter endpoint selected by this route, with no markup or discount. Unlike GLM 5.2, reasoning is always on for this endpoint and cannot be disabled — control depth with `reasoning_effort` instead.
At a glance
Complex software engineering and long-horizon agents — Z.ai's newest reasoning flagship with a 1M-token context window.
Pricing comparison ($/1M tokens)
| Provider | Input | Output | vs QSP |
|---|---|---|---|
| QuickSilver Pro | $0.60 | $2.20 | — |
| OpenRouter (z-ai/glm-5.3) | $0.60 | $2.20 | same |
| OpenAI (GPT-4o) | $2.50 | $10.00 | 78% lower |
When to use
Reach for GLM 5.3 on the hardest Z.ai-family workloads: repo-scale refactors, plan-then-act agents coordinating many tool calls over long horizons, and tasks that need both a large working set in its 1M-token context and up to 131K tokens of output in one call. It succeeds GLM 5.2 at the same per-token price, so for new projects that want deliberate reasoning it's the default pick of the family. Reasoning is always on; use `reasoning_effort` to trade depth against latency and cost.
When to use something else
Reasoning is mandatory here, so it spends thinking tokens even on trivial turns — if you want a GLM that replies directly, GLM 5.2 is the better family pick with direct replies by default. For routine chat, short-context codegen, or single-shot tasks, the per-token price and reasoning overhead are overkill — DeepSeek V4 Flash ($0.06/$0.18) or V4 Pro ($0.70/$2.10) land most of those for less. If you have an existing prompt suite tuned on GLM 5.2, A/B before switching — different prices, and traces and tool-call cadence differ. For agentic coding specifically, also A/B against Kimi K2.7 Code.
Quickstart (curl)
curl https://api.quicksilverpro.io/v1/chat/completions \
-H "Authorization: Bearer $QSP_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "glm-5.3",
"messages": [{"role": "user", "content": "Hello!"}]
}'OpenAI-compatible. One-line migration via base_url.
FAQ
Reasoning is always on — it is mandatory on this endpoint and cannot be disabled (a request that tries to turn it off is rejected upstream). Use `reasoning_effort` to trade depth against latency and cost. Reasoning tokens bill as output tokens and are drawn from your `max_tokens` budget before the visible answer, so set `max_tokens` generously or the reply can come back truncated. If you want a GLM without always-on thinking, use GLM 5.2 — direct replies by default.
GLM 5.3 is Z.ai's successor release (2026-08-18) with improved complex software engineering and long-horizon agent performance, the same 1M-token context window, and an explicit 131K max-output limit. One behavioral difference matters: GLM 5.3 reasoning is mandatory and cannot be disabled, while GLM 5.2 replies directly by default. GLM 5.3 costs $0.60 / $2.20 and GLM 5.2 costs $0.70 / $2.20 per million input / output tokens; upgrading is a model-ID swap — budget extra output tokens for the always-on thinking.
Yes — GLM 5.3 is an OpenAI-compatible chat completions endpoint on QuickSilver Pro (the Responses API works too). Set base_url=https://api.quicksilverpro.io/v1, paste your QSP key, and use model="glm-5.3". Streaming, tool calling (`tool_choice: "auto"` — this endpoint rejects forcing a specific function), and usage.cost accounting all work. `response_format: json_schema` is not enforced on this endpoint yet; if you need strict structured output, use GLM 5.2.
$0.60 input / $2.20 output and $0.20 cache read per million tokens, matching the route-selected OpenRouter endpoint (inceptron fp4) with no markup or discount. The route uses its pinned provider order or the cheapest eligible endpoint under sort: price and its quantization filters; the /models headline can differ. More expensive fallback hosts do not change your price. Use base_url=https://api.quicksilverpro.io/v1 and model="glm-5.3".