Gemini 3.5 Flash API

google/gemini-3-5-flash
Gemini 3.5 Flash model narrows the gap between Flash-tier speed and Pro-level reasoning.
Context
1M tokens
Input
$1.5 / 1M tokens
Output
$9 / 1M tokens
Released
May 19, 2026

Overview

What Is Gemini 3.5 Flash API?

With Gemini 3.5 Flash API, Google introduces a new generation of multimodal AI designed for real-world production workloads, high-speed automation, advanced coding assistance, and scalable agentic workflows. Whether you're building AI-powered SaaS tools, enterprise copilots, customer support systems, automation pipelines, or next-generation coding agents, Gemini 3.5 Flash delivers the performance modern applications demand.

Unlike traditional heavyweight models that often sacrifice latency for reasoning quality, Gemini 3.5 Flash focuses on delivering advanced reasoning, coding capability, and multimodal understanding at Flash-level speed.

__wf_reserved_inherit

What Gemini 3.5 Flash brings to the table

Everything developers are expecting based on current leaks, official Gemini 3 series documentation, and early tester reports.

Near-Pro reasoning

Expected to come significantly closer to Gemini 3.1 Pro's reasoning quality while remaining faster and cheaper. Early testers report that the long-standing "lazy model" problem has been largely addressed.

1 million token context

Carries forward the full 1M token input context window from the Gemini 3 generation — large enough to fit entire codebases, lengthy documents, and complex multi-turn agentic conversations in a single call.

Configurable thinking levels

Like Gemini 3 Flash before it, 3.5 Flash is expected to support four thinking levels — minimal, low, medium, and high — letting developers trade off reasoning depth against latency and cost per request.

Full multimodal support

Accepts text, images, audio, video, and PDFs as input. Carries forward the improved audio grounding from the Gemini 3 series, including better handling of accented speech and background noise.

Stronger grounding

Leaked details point to improved search grounding reliability — a consistent pain point in earlier Gemini Flash models. If accurate, this could make 3.5 Flash significantly more useful for real-world research and factual tasks.

Gemini 3.5 Flash API Pricing

  • сached input: $0.065
  • audio input: $1.30

< 200K tokens

  • 1M input tokens: $0.65
  • 1M output tokens: $3.90

> 200K tokens

  • 1M input tokens: $3.25
  • 1M output tokens: $23.40

Model specs at a glance

Specification Details
Model ID gemini-3.5-flash-preview
Developer Google DeepMind
Model series Gemini 3.5 (Flash tier)
Context window 1,000,000 input tokens
Max output ~64,000–65,000 tokens (consistent with Gemini 3 Flash)
Knowledge cutoff January 2026 (per leaked pricing page)
Input modalities Text · Images · Audio · Video · PDFs
Output modalities Text
Thinking levels Minimal · Low · Medium · High
Tools supported Google Search · URL Context · Code Execution · Function Calling · Maps Grounding
Context caching Yes (reduces cost on repeated prompts)

Four thinking levels, one model

The thinking_level parameter lets you dial reasoning depth per request — critical for high-volume workloads where you don't want to pay Pro prices for simple tasks.

Thinking Level Description Best Use Cases
Minimal Fastest, lowest cost. Similar latency to a non-reasoning model. Classification, routing, and simple transformations where extended thought adds no value.
Low Light reasoning with balanced speed and quality. Summarization, translation, and basic Q&A for cost-efficient content pipelines.
Medium Balanced performance and reasoning depth. The practical default for most apps. Code generation, document analysis, and multi-step instructions.
High Full reasoning chain with near-Pro output quality for advanced tasks. Complex logic, math, research synthesis, and multi-hop reasoning.

Gemini 3.5 Flash vs. the current Gemini 3 lineup

Feature Gemini 3.1 Flash-Lite Gemini 3 Flash Gemini 3.5 Flash Gemini 3.1 Pro
Tier Flash-Lite Flash Flash (premium) Pro
Context window 1M tokens 1M tokens 1M tokens 2M tokens
Thinking levels ✓ 4 levels ✓ 4 levels ✓ 4 levels ✓ 4 levels
Reasoning quality Good Very good Near-Pro Best-in-class
Latency Fastest Fast Fast Slower
Grounding improvements Moderate Good Improved Best

What Gemini 3.5 Flash is built for

Based on everything we know so far, here's where 3.5 Flash will shine over the existing lineup.

Complex agentic workflows that need speed

Multi-step agent loops have historically been a weak point for Flash models — they'd drop context, hallucinate tool parameters, or give superficial answers mid-chain. 3.5 Flash is expected to handle these with the reliability previously reserved for Pro, at a fraction of the cost and latency.

Coding assistants and IDE integrations

Near-Pro reasoning means 3.5 Flash should handle real-world debugging, code review, and refactoring tasks that currently require reaching for Pro. The January 2026 knowledge cutoff also means better awareness of recent frameworks, package versions, and breaking API changes.

Real-time search-grounded applications

If the grounding improvements hold up at GA, 3.5 Flash should be significantly more reliable for applications where hallucination is costly — customer-facing research tools, fact-checking pipelines, and RAG systems that need accurate snippet ranking alongside low latency.

Interactive chat with complex documents

The 1M token context and expected reasoning improvements make it a strong fit for document Q&A products, legal contract analysis, and financial report parsing — tasks where Flash's speed matters but where previous Flash models sometimes gave shallow answers on dense material.

Multimodal pipelines (video, audio, images)

Gemini 3.5 Flash inherits the full multimodal stack, including improved audio input quality over the 2.5 generation. For applications ingesting meeting recordings, product photos, or mixed-media documents, it provides a single model rather than separate specialized endpoints.

‍

Uptime and performance

  • Uptime (24h): 100%
  • Uptime (7d): 98.0%
  • Availability (24h): 100%
  • Error rate (24h): 0%
  • End-to-end latency (24h median): 9.7s
  • Time to first token (24h median): 8.5s
  • Throughput (24h median): 1322.2 tok/s

Measured on the AI/ML API gateway across live traffic. Figures are medians unless stated. Last updated 2026-10-12.

Use cases

Gemini 3.5 Flash is documented as suited to agentic workflows, coding tasks, and multi-week enterprise processes.

It is also described as well-suited for rapid agentic loops, including complex coding cycles and iterations.

The model is further presented as a strong choice for sub-agent deployment, multi-step workflows, and long-horizon tasks at scale.

Google also says it can be used to develop new applications, maintain codebases, and help prepare financial documents.

How to use Gemini 3.5 Flash API

Install any OpenAI-compatible SDK, point it at api.aimlapi.com/v1, and set the model to google/gemini-3-5-flash.
import requests

r = requests.post(
    "https://api.aimlapi.com/v1/chat/completions",
    headers={"Authorization": "Bearer " + AIMLAPI_KEY},
    json={
      "model": "google/gemini-3-5-flash",
      "messages": [
        {
          "role": "user",
          "content": "Hello!"
        }
      ]
    },
)
print(r.json())
const r = await fetch("https://api.aimlapi.com/v1/chat/completions", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.AIMLAPI_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "model": "google/gemini-3-5-flash",
    "messages": [
      {
        "role": "user",
        "content": "Hello!"
      }
    ]
  }),
});
console.log(await r.json());
curl -X POST https://api.aimlapi.com/v1/chat/completions \
  -H "Authorization: Bearer $AIMLAPI_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"google/gemini-3-5-flash","messages":[{"role":"user","content":"Hello!"}]}'

OpenAI-compatible — swap the base URL and it works with your existing SDK.

Gemini 3.5 Flash API Pricing

TypePrice
Input
$1.5 / 1M tokens
Output
$9 / 1M tokens
Cached input
$0.15 / 1M tokens

Gemini 3.5 Flash Benchmarks

BenchmarkScoreWhat it measuresSourceRetrieved
Intelligence
33.6
Composite score across standardised reasoning, knowledge and problem-solving evaluations, measured independently by Artificial AnalysisSourceSeptember 12, 2026

Gemini 3.5 Flash vs other models

ModelInputOutputContextBest for
$1.5 / 1M tokens
$9 / 1M tokens
1M tokens
Reasoning + agents
$5 / 1M tokens
$30 / 1M tokens
1M tokens
Reasoning + agents
$2 / 1M tokens
$10 / 1M tokens
1M tokens
Balanced coding + agents
$3 / 1M tokens
$15 / 1M tokens
1M tokens
Long-context, multimodal & agentic workflows

Frequently asked questions

Gemini 3.5 Flash has a 1,048,576 tokens context window and can return up to 65,536 tokens.

Gemini 3.5 Flash takes audio, image, text, video as input and returns audio, text.

Use google/gemini-3-5-flash as the model id. Requests go to https://api.aimlapi.com/v1/chat/completions.

Gemini 3.5 Flash is priced at input $0.65 / 1M tokens, output $3.9 / 1M tokens, cached input $0.065 / 1M tokens.

Yes, Gemini 3.5 Flash can stream responses as they are generated.

Yes, Gemini 3.5 Flash accepts image input alongside text.

Gemini 3.5 Flash was built by Google.

It supports function calling, parallel tool calls, and structured output generation.

Start building with Gemini 3.5 Flash

Get API Key
1000+ models, one API.