Compare

Gemini 3.1 Pro vs FLUX 3 Image Klein

Pricing per million tokens, context window, capabilities — pulled from each provider's public docs. All 2 are available via the same AIgateway OpenAI-compatible endpoint; flip the model string to switch.

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Gemini 3.1 Pro
google/gemini-3.1-pro
FLUX 3 Image Klein
black-forest-labs/flux-3-image-klein
Provider
Google
Black Forest Labs
Family
Gemini 3
FLUX
Modality
text
image
Context window
1,000,000 tok
—
Max output
65,536 tok
—
Released
2026-05-22
2026-10-16
License
Proprietary
Open-weight
Input price
$2.00 /1M
—
Output price
$12.00 /1M
—
Cache read
$0.200 /1M
—
Per image
—
$0.0090 /img
Tools
yes
—
Streaming
yes
—
Vision
yes
—
JSON mode
yes
—
Reasoning
yes
—
Prompt caching
yes
—
Batch API
—
—
Try it
Open in playground →
View model →
Gemini 3.1 Pro
google/gemini-3.1-pro
Full spec →

Google's most intelligent Gemini model with improved reasoning, a medium thinking level, and a 1M token context window.

Strengths
  • 2M-token context
  • Native video + audio input
  • Cheapest long-context reasoning
Use cases
Video understandingVery long-document RAGCodebase-scale reasoning
FLUX 3 Image Klein
black-forest-labs/flux-3-image-klein
Full spec →

FLUX 3 Image Klein is Black Forest Labs' 5.6B-parameter image model for text-to-image, image editing, and multi-reference generation with up to 10 reference images. It supports native 4K output and bounding-box layout control.

Strengths
  • Text-to-image generation
  • Creative control
Use cases
Marketing assetsProduct mockupsConcept art

Benchmarks

Gemini 3.1 Pro
FLUX 3 Image Klein
Long-Context
94.2
—
MMLU
89.6
—

Source: each provider's published benchmarks. Higher is better. Run an eval to compare on your own data.

Compare with another

Gemini 3.1 Pro vs Claude Opus 4.7
google/gemini-3.1-pro · anthropic/claude-opus-4.7
Gemini 3.1 Pro vs GPT-5.4
google/gemini-3.1-pro · openai/gpt-5.4
Gemini 3.1 Pro vs Claude Sonnet 4.6
google/gemini-3.1-pro · anthropic/claude-sonnet-4.6
Gemini 3.1 Pro vs Kimi-K2.7-Code
google/gemini-3.1-pro · moonshot/kimi-k2.7-code
Gemini 4 Argon vs Gemini 3.1 Pro
google/gemini-4-argon · google/gemini-3.1-pro
Gemini 4 Argon vs FLUX 3 Image Klein
google/gemini-4-argon · black-forest-labs/flux-3-image-klein
Claude Sonnet 5.5 vs Gemini 3.1 Pro
anthropic/claude-sonnet-5.5 · google/gemini-3.1-pro
Claude Sonnet 5.5 vs FLUX 3 Image Klein
anthropic/claude-sonnet-5.5 · black-forest-labs/flux-3-image-klein
Claude Opus 5.5 vs Gemini 3.1 Pro
anthropic/claude-opus-5.5 · google/gemini-3.1-pro
SWITCH BETWEEN THEM

One key, all 2, one line different.

from openai import OpenAI

client = OpenAI(
    base_url="https://api.aigateway.sh/v1",
    api_key="sk-aig-...",
)

# Gemini 3.1 Pro
client.chat.completions.create(
    model="google/gemini-3.1-pro",
    messages=[{"role":"user","content":"hello"}],
)

# FLUX 3 Image Klein
client.chat.completions.create(
    model="black-forest-labs/flux-3-image-klein",
    messages=[{"role":"user","content":"hello"}],
)
Get an AIgateway keyRun an eval on these →