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Open SourceAlibaba

Qwen3.5 4B

Qwen3.5 4B is a small chat model from Alibaba's Qwen3.5 family, positioned at roughly 4 billion parameters based on its name.

License Open Source
Input from
$0.040 / 1M tokens
on Empirio Labs · 1 provider
Output from
$0.070 / 1M tokens
on Empirio Labs

API Pricing

ProviderInput / 1MOutput / 1MCached / 1M
$0.040$0.070$0.020

Prices updated daily. Last check: Oct 30, 2026

Compare API pricing for every Qwen model →

Qwen3.5 4B pricing by provider

Input, output, and batch rates, plus alternatives, for one provider at a time.

Performance & Benchmarks

Source: Artificial Analysis →
Output Speed
14.8 t/s
Latency (TTFT)
704ms

Benchmarks measured Oct 2026. Scores are independent evaluations, not vendor-reported.

Model Details

General

Creator
Alibaba
Modalities
Text

Capabilities

Open Source
Yes

Strengths & Limitations

Strengths

  • Small parameter class (~4B by name) keeps memory footprint low relative to mid-size and large chat models
  • Measured time to first token of roughly 580 ms on the endpoint benchmarked by Artificial Analysis, suitable for interactive request patterns
  • Part of Alibaba's Qwen3.5 family, so prompt formats and tooling are shared with larger siblings if you need to scale up
  • Size class is typically inexpensive to serve at high request volume compared with larger models in the same family
  • Small models in this range are commonly deployable on a single mid-range GPU, making self-hosting a practical alternative to API serving
  • Positioned for batch text processing where per-request capability ceilings matter less than aggregate cost

Limitations

  • A ~4B parameter model generally trails larger family members on complex reasoning, long-horizon coding, and multi-step agentic tasks
  • We do not currently track a confirmed context window for this entry, so verify limits with your provider before designing long-document workflows
  • No accuracy benchmark scores are recorded in our database for this model, only serving speed measurements
  • The 17.5 output tokens per second figure we track comes from one measured endpoint and may not represent what you observe elsewhere
  • Modality support (for example image input) is not confirmed in our data, so do not assume multimodal input

Key Features

•Chat-format conversational model in Alibaba's Qwen3.5 family
•Small parameter class indicated by the 4B designation
•Measured output throughput of approximately 17.5 tokens per second (Artificial Analysis)
•Measured time to first token of approximately 580 ms (Artificial Analysis)
•Shared family lineage with larger Qwen3.5 variants for prompt and workflow portability
•Size profile suited to single-GPU or cost-constrained serving
•Multiple-provider availability tracked in the pricing table on this page

About Qwen3.5 4B

Qwen3.5 4B is a conversational language model released by Alibaba as part of its Qwen3.5 model family. The "4B" in the name indicates a parameter count in the range of about 4 billion, which places it at the small end of the family rather than among its larger siblings. Models in this size class are typically used where serving cost, memory footprint, or local deployment matter more than maximum capability on hard reasoning tasks. Our database records Qwen3.5 4B as a chat model and tracks independent serving measurements for it: approximately 17.5 output tokens per second and a time to first token of roughly 580 milliseconds, as measured by Artificial Analysis. Those figures reflect a specific measured endpoint rather than a property of the model itself — throughput and latency for small models vary widely between providers, quantization levels, and batch settings, and a 4B model is generally capable of much higher throughput on dedicated hardware than a shared API endpoint may deliver. We do not currently track a confirmed context window, modality list, or benchmark accuracy scores for this entry. In practice, small Qwen chat models are used for high-volume, cost-sensitive text work — classification, extraction, summarization, routing, and drafting — and as a local or on-premise option where a smaller parameter count fits available GPU memory. If your workload involves long multi-step reasoning, complex agentic tool chains, or difficult code generation, the larger members of the Qwen3.5 family or larger models from other creators are the more usual comparison points. Check the pricing table on this page for the providers currently serving Qwen3.5 4B and how their offerings differ.

Common Use Cases

Qwen3.5 4B fits workloads where volume and unit cost dominate the decision: bulk classification and tagging, entity and field extraction from semi-structured text, short summarization, intent routing in front of a larger model, chat assistants with narrow scope, and content drafting where a human reviews the output. Its small parameter class also makes it a candidate for self-hosted or edge deployments where a larger model would not fit available GPU memory, and for latency-sensitive interactive features given the sub-second time to first token recorded in our benchmark data. It is a weaker fit for tasks that reward scale — difficult mathematical reasoning, large refactoring jobs across a codebase, or long agentic loops with many tool calls — where a larger Qwen3.5 variant or a comparable mid-size model from another creator is the more common choice.

Frequently Asked Questions

How much does Qwen3.5 4B cost to use?

Pricing varies by provider and by pricing model — some hosts bill separately for input and output tokens, others bundle capacity or offer dedicated deployments, and self-hosting shifts the cost to GPU rental instead. Because rates change frequently, see the pricing table on this page for the current figures from each provider we track.

What is Qwen3.5 4B best used for?

It suits high-volume, cost-sensitive text processing: classification, extraction, summarization, routing, and narrow-scope chat assistants. Its small size also makes it a practical option for self-hosted deployments on modest GPU hardware.

How does Qwen3.5 4B compare with larger Qwen3.5 models?

At roughly 4 billion parameters it is at the small end of the family. Larger Qwen3.5 variants generally handle complex reasoning, coding, and multi-step agentic work better, while the 4B model trades some of that capability for a lower memory footprint and cheaper serving at scale.

What context window does Qwen3.5 4B support?

Our database does not currently record a confirmed context window for this entry. Check the documentation of the specific provider you plan to use, since effective limits can also differ between hosts of the same model.

How fast is Qwen3.5 4B?

The measurement we track from Artificial Analysis shows roughly 17.5 output tokens per second with a time to first token of about 580 ms. That reflects one measured endpoint; throughput for a model this size can be considerably higher on dedicated hardware or with different quantization and batching settings.