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

Guidance – Free

Smiley

Interface

Cyber Duotone - Free

Smiley Frown

Mail Chat Smiley

Core Duo

Smiley Emoticon Sad

Plump Line

Smiley Grumpy

Plump Flat

Smiley Excited

Smiley Emoticon Smile

Freehand Duotone

Smiley Lol

Smiley Cheeky

Plump Gradient

Smiley Blessed

Plump Solid

Smiley Sick

Smiley Sparks

Plump Neon

Smiley Happy

Smiley Smirk

Smiley Rich

Flex Solid

Smiley Worried

Ultimate Bold

Smileys

Ultimate Duotone

Smiley Unhappy

Ultimate Regular

Smiley Dizzy

Plump Flat - Free

Smiley Indiferent

Core Remix

Smiley Content

Core Pop

Smiley Calm

Core Line

Smiley Crying 1

Flex Remix

Smiley Cool

Sharp Remix

Smiley Wink

Sharp Solid

Sharp Line

Smiley Frustrated

Core Solid

Smiley Thrilled

Smiley Laughing 2

Smiley Pin 2

Pins

Smiley Decode

Core Remix - Free

Core Flat - Free

Smiley Drool

Core Solid - Free

Smiley Nauseas

Smiley Trouble

Sharp Solid - Free

Smiley Shocked

Ultimate Light - Free

Laptop Smiley 1

Computers Devices Electronics

Smiley Very Happy 1

Smiley Drop

<p>Flex is a fluid icon family inspired by nature's curves. It replaces rigid geometry with smooth, flowing forms. The Line variant features elegant strokes with organic curves.</p>

Flex Line

**Summary**: Flex's most refined sub-style — 1px continuously curving organic stroke on a 14px grid, the most visually elegant line icon available, suited to consumer and lifestyle products where icons should feel modern and naturally fluid. Flowing nature-inspired paths communicate organic forms rather than systematic grids. The tone signals refined motion: "we are in flow." Best for health, wellness, and lifestyle apps where organic visual language mirrors product values; personal finance and fintech wanting a human register; and creative tools where visual craft matters; best deployed at 24px+ where the organic curve quality is fully visible.

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

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## Fit & Recommendation

### Primary use cases

- Consumer products where the visual language should feel modern and naturally elegant
- Health, wellness, and lifestyle apps where organic visual language mirrors product values
- Personal finance and fintech products that want to feel human and approachable
- Creative and design-adjacent tools where visual craft matters
- Products with generous spacing and large icon display sizes (24px+)
- Navigation where icons should complement illustration or photography, not compete

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## Brand & Cultural Identity

### What it communicates

> "We are refined and in motion."

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## Visual & Technical Specs

### Visual properties

| Property | Value |
|----------|-------|
| Stroke weight | 1px |
| Fill | None |
| Corner treatment | Smooth fluid curves throughout — no geometric corners anywhere |
| Color | Monochrome |

### Emotional Scores

Flex Line is one of the warmer sub-styles in the catalog — organic flowing curves create warmth, though the 1px weight and cool monochrome colour slightly offset this. It is among the softest sub-styles in the catalog — the 1px stroke with continuously flowing curves is among the softest line constructions possible. It is one of the friendlier sub-styles in the catalog — organic curves lean friendly, with the refined thinness of the stroke pulling slightly toward elegance. It is one of the more playful sub-styles in the catalog in a considered way — flowing organic curves are fluid and refined rather than casual, sitting on the friendlier side of the midpoint. On its human↔mechanical character, it is one of the most human-feeling sub-styles in the catalog — nature-inspired curves communicate flowing organic forms, not systematic grids.

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## Pairing & Compatibility

### Typography pairing

- **Primary**: Plus Jakarta Sans — humanist warmth with subtle stroke contrast; shares the organic flowing quality
- **Alternative**: Outfit — clean humanist, modern; flowing curves sit naturally alongside
- **Editorial**: Libre Baskerville Light — for lifestyle contexts, serif stroke contrast echoes organic curve variation
- **Body**: Inter Regular — universal readable body, steps back to let Flex Line lead
- **Avoid**: IBM Plex Sans, Neue Haas Grotesk, cold monolinear grotesque — perfectly constructed geometric letters fight the organic language


<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

Smiley Sick icon - Flex Line Set

Download Smiley Sick SVG vector or transparent PNG icon in Line, Stroke style(s) for Sketch and Figma. It belongs to Flex Line vectors SVG collection.