# GLM-5.3-FlashX GLM-5.3-FlashX is the high-speed serving option for Z.AI's natively multimodal GLM-5.3-Flash weights, aimed at latency-sensitive coding and agent loops. It keeps the same always-on thinking, tool calling, and visual understanding of interfaces and rendered output as its Flash sibling, trading a higher rate for faster responses. Its published context window is 1,000,000 tokens. The advertised input rate is $0.37 per million input tokens. The advertised output rate is $1.25 per million output tokens. - Model identifier: ` zai/glm-5.3-flashx ` - Creator: Z.AI - Providers: Z.AI - Model type: Text generation - Canonical model page: [GLM-5.3-FlashX]() - API availability: Listed as serving through Impossibl. ## Providers Z.AI hosts GLM-5.3-FlashX. Impossibl routes your request intelligently and handles failover automatically when a provider is down. | Provider | Endpoint location | Routes | Verified context window | Tool calling | | --- | --- | --- | --- | --- | | Z.AI | Not specified | 1 | Not verified | Not verified | The model price applies whichever provider serves the request. Endpoint locations do not guarantee inference residency. ## Specs and Capabilities - Context window: 1,000,000 tokens - Maximum output tokens: Not published in the public catalog; this is separate from the context window. - Inputs: text, image - Outputs: text - Tool calling: Not published ## API access Use ` zai/glm-5.3-flashx ` as the model identifier through the Impossibl API. Published API endpoints: - ` /v1/chat/completions ` [API quickstart]() ยท [Models and billing documentation]() ## Published API prices All rates are in USD. An unpublished rate is unknown, not zero. Workspace-specific pricing, taxes, balance-purchase fees, billing adjustments, and tool charges can affect the amount paid. | Usage | Published base rate | Billing unit | | --- | --- | --- | | Input | $0.37 | per million input tokens | | Output | $1.25 | per million output tokens | | Cache read | $0.075 | per million cached input tokens | | Cache write (default retention) | Not published | per million tokens | | Cache write (one-hour retention) | Not published | per million tokens | | Audio input | Not published | per million audio input tokens | ## Availability and retirement The model is listed as serving. No retirement is announced in the current public catalog. ## Frequently asked questions ### What is GLM-5.3-FlashX? GLM-5.3-FlashX is the high-speed serving option for Z.AI's natively multimodal GLM-5.3-Flash weights, aimed at latency-sensitive coding and agent loops. It keeps the same always-on thinking, tool calling, and visual understanding of interfaces and rendered output as its Flash sibling, trading a higher rate for faster responses. Sources: [Z.AI GLM-5.3-Flash/FlashX model documentation](); [Vercel AI Gateway model listing]() ### How much does GLM-5.3-FlashX cost? GLM-5.3-FlashX costs $0.37 per million input tokens and $1.25 per million output tokens through the Impossibl API. Cache reads cost $0.075 per million tokens. All rates are in USD. ### What is the context length of GLM-5.3-FlashX? GLM-5.3-FlashX has a 1,000,000-token context window through the Impossibl API. ### What inputs and outputs does GLM-5.3-FlashX support? GLM-5.3-FlashX accepts text and image as input. GLM-5.3-FlashX returns text. ### How do I use GLM-5.3-FlashX through an API? GLM-5.3-FlashX is available through the Impossibl API. Use zai/glm-5.3-flashx as the model identifier with /v1/chat/completions. The quickstart explains how to create an API key and send your first request. ## Sources and related links Prices, limits, capabilities, endpoints, and availability come from the public Impossibl catalog. Creator documentation supplies descriptions and release dates where available; it does not override the published API offering. - [Public Impossibl model catalog]() - [Full model directory as JSON]() - [GLM-5.3-FlashX: model details and pricing]() - [Model directory]() - [Z.AI GLM-5.3-Flash/FlashX model documentation]() - [Vercel AI Gateway model listing]()