Qwen3.5 4B is a compact 4 billion parameter multimodal model that pairs vision-language capability with a hybrid architecture combining Gated DeltaNet and Mixture-of-Experts layers. It supports a 262,144 token native context window, extensible toward roughly one million tokens with YaRN scaling, and reports MMLU-Pro 79.1. Trained with early fusion on multimodal tokens, it handles image-text-to-text tasks and video understanding while staying efficient relative to larger models. It runs in thinking mode by default, generating reasoning before responses. The model suits knowledge-intensive tasks, visual reasoning, and agent-based applications with tool calling across more than 200 languages where a small multimodal model is preferred.
Call Qwen3.5 4B on Opper with the OpenAI SDK. Sign up without a credit card. Get started
Qwen3.5 4B runs on 2 different routes through the Opper gateway. Compare residency, zero data retention and training posture at a glance, with full data-handling detail per route below.
| Provider | Region | Zero data retention | Training | Input | Output | Cache read |
|---|---|---|---|---|---|---|
| US | No | $0.03 | $0.15 | Input price | ||
| Multi | No | $0.04 | $0.07 | $0.02 |
One of Qwen3.5 4B's 2 routes is on the monitoring board, so the figure below is that provider's availability rather than the model's.
Name a second model in the same request and the gateway tries it on retriable errors, so a busy hour never has to reach your users. Set up a fallback chain.
Measured over the last 30 days from each provider's official status feed via StatusGator. Refreshed hourly. 1 further route is not on the board yet. See uptime for every provider Opper monitors.
Each route hosting Qwen3.5 4B has its own privacy posture, residency, and GDPR terms. Postures are maintained by Opper with a last-verification timestamp.
Zero data retention: nothing is logged, held for abuse monitoring or used for training. No training on customer data. US; unknown; DPA available.
Zero data retention: nothing is logged, held for abuse monitoring or used for training. No training on customer data. GLOBAL; SCCs; DPA available.
Independent benchmark scores — composite indices for reasoning, coding, and math, plus individual eval scores where available.
Call Qwen3.5 4B through the Opper gateway with one API key. Opper is drop-in compatible with the OpenAI, Anthropic and Google AI SDKs.
Qwen3.5 4B is a premium model on Opper. Sign up needs no credit card: you get an API key straight away and the free models work in the playground and the API. Add a card to use premium models, pay-as-you-go with no minimum.
Copy this and paste it into a coding agent like Claude Code, Cursor or Codex and it'll wire up Opper for you.
import OpenAI from "openai";const client = new OpenAI({apiKey: process.env.OPPER_API_KEY,baseURL: "https://api.opper.ai/v3/compat",});const completion = await client.chat.completions.create({model: "qwen3.5-4b",messages: [{ role: "user", content: "Hello" }],});console.log(completion.choices[0].message.content);
Side-by-side on privacy, EU hosting, pricing, and benchmarks.
