Interface Essential

Business

Images Photography

Money Shopping

Programming

Computer Devices

Phone

Mail

Map Travel

Food Drink

Nature Ecology

Entertainment

Shipping

Culture

Health

Work Education

Artificial Intelligence

Arrows

Streamline 3.0

Ultimate

Core

Flex

Sharp

Plump

Micro

Freehand

Streamline Material

Nova

Cyber

Streamline Vault

Logos

Pixel

Google Material

Tabler

Remix

Feather

Iconoir

Carbon

Solar

Lucide

Brand Logos

Bootstrap

Atlas

Unicons

Ionic Icons

Phosphor

MingCute

Font Awesome

Majesticons

Mynaui

Radix

Heroicons

Flagpack

Flex Gradient - Free

Fingerprint 1

Flex Solid - Free

Plump Gradient - Free

Fingerprint 2

Core Flat - Free

Sharp Gradient- Free

Plump Remix - Free

Sharp Remix - Free

Core Remix - Free

Plump Line - Free

Outlined Line - Streamline Material

Fingerprint

Common Actions

Plump Line

Sharp Neon

Sharp Remix

Core Duo

Flex Solid

Flex Pop

Flex Line

Plump Flat

Sharp Duo

Flex Duo

Plump Solid

Core Solid

Sharp Solid

Plump Gradient

Core Flat

Rounded Line - Streamline Material

Cyber Line

Login

Core Line

Flex Line - Free

Flex Duo - Free

Cyber Duotone

Core Solid - Free

Sharp Line - Free

Core Line - Free

Sharp Line

Core Duo - Free

Sharp Line - Streamline Material

Sharp Gradient

Sharp Pop

Sharp Flat

<p>Flex is a fluid icon family inspired by nature's curves. The Solid variant features smooth, filled shapes with rounded edges for a friendly, organic aesthetic.</p>

**Summary**: Flex's impact sub-style — opaque fills on fluid organic silhouettes, providing strong visual presence while preserving the flowing, nature-inspired quality that distinguishes Flex from geometric solid sets. Organic silhouette edges soften the fill hardness, keeping the register modern and grounded rather than authoritative or cold. The tone signals organic groundedness: "we are grounded and solid without being rigid." Best for active and selected states paired with Flex Line, feature callouts in lifestyle and consumer apps, photography-heavy layouts where organic icon silhouettes complement imagery, and navigation where Flex Line is too fragile at small sizes.

**Last updated**: 2026-04-23

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## Fit & Recommendation

### Primary use cases

- Feature callouts and primary actions where the organic filled silhouette creates distinction
- Navigation in apps where Flex Line is too fragile at small sizes
- Badge, tag, and indicator systems with a modern organic aesthetic
- Photography-heavy layouts where organic icon silhouettes complement imagery
- Active and selected states paired with Flex Line for inactive states

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## Brand & Cultural Identity

### What it communicates

> "We are grounded and organic."

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## Visual & Technical Specs

### Visual properties

| Property | Value |
|----------|-------|
| Stroke weight | None |
| Fill | Opaque fill with transparent cutouts — background visible through cutout areas |
| Corner treatment | Smooth rounded organic silhouettes — shapes flow rather than contain |
| Color | Monochrome |

### Emotional Scores

Flex Solid is one of the friendlier sub-styles in the catalog in a grounded way — solid black fills on organic silhouettes read as modern and natural, with the warmth of flowing shapes partially offsetting the coldness of a black fill. It is somewhat soft — solid fills add visual weight, but organic silhouette edges soften the overall reading. It is somewhat friendly — organic solid silhouettes are modern and considered, landing between warmly approachable and formal. It is somewhat playful in a restrained sense — the organic quality reads as natural rather than playful, with the solid fill giving authority without severity. On its human↔mechanical character, it is one of the more human-feeling sub-styles in the catalog — organic silhouettes read as natural forms, and the fill does not mechanise them.

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## Pairing & Compatibility

### Typography pairing

- **Primary**: Plus Jakarta Sans SemiBold — weight-appropriate for solid fills while retaining humanist warmth
- **Alternative**: Outfit SemiBold — modern, clean, compatible with organic silhouettes
- **Body**: Inter Regular or Mulish
- **Avoid**: Heavy grotesque display at maximum weight — overwhelms organic solid silhouettes


<p>Flex is a fluid icon family inspired by nature’s curves. It favors smooth, flowing forms. More organic than Core and subtler than the chunky Plump. Read about the <a href="https://blog.streamlinehq.com/flex/" rel="noopener noreferrer" target="_blank">design process</a>.</p>

Fluid icons

Fingerprint Check Validate

Fingerprint Check Validate icon - Flex Solid Set

Download Fingerprint Check Validate SVG vector or transparent PNG icon in Solid, Bold, Glyph style(s) for Sketch and Figma. It belongs to Flex Solid vectors SVG collection.