Disclosure: this guide is from the RouterBase team.
DeepSeek V4.1 Flash is now available on RouterBase. One integration detail is easy to miss: a model page's URL slug is not necessarily its API identifier. For this model, the catalog returns deepseek/deepseek-v4.1-flash.
Verify the identifier without running inference
Save the following as check-model.mjs and run it with Node.js 18 or later. It requests the public catalog; it does not send a prompt or require an API key.
const response = await fetch("https://routerbase.com/v1/models");
if (!response.ok) throw new Error(`Catalog HTTP ${response.status}`);
const { data } = await response.json();
const model = data.find(m => m.id === "deepseek/deepseek-v4.1-flash");
if (!model) throw new Error("Model is absent from the catalog");
console.log(model.id, model.pricing);
On September 14, 2026, the catalog returned that exact ID and listed $0.30 per million input tokens and $1.20 per million output tokens. A successful catalog lookup confirms the listing, not the quality or latency of a generated answer.
Configure the client separately
Use https://routerbase.com/v1 as the base URL and the exact catalog ID as the model. Provide your RouterBase API key through a server-side environment variable. Do not substitute the model page slug or an upstream provider alias.
If the identifier disappears from a future catalog response, stop and inspect the current documentation rather than silently choosing another model. After configuration, run a small application-level evaluation with representative prompts and explicit acceptance criteria.
DeepSeek V4.1 Flash model details
Sources: RouterBase API documentation and the public model catalog. Pricing checked September 14, 2026.
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