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

Plump Line - Free

Slack

Core Remix - Free

Plump Solid - Free

Core Solid - Free

Core Line - Free

Plump Duo - Free

Core Gradient - Free

Core Duo - Free

Core Flat - Free

Plump Flat - Free

iOS 14

iOS icons

Ultimate Bold

Slack Logo

Messaging Video Meetings

Sharp Neon

Logo

Plump Neon - Free

Plump Remix

Ultimate Regular

Ultimate Light

Core Neon

Core Line

Plump Line

Flex Solid

Plump Flat

Plump Duo

Core Flat

Core Remix

Flex Line

Channel Slack

Signs

Core Solid

Logos Line - Free

Messaging Video Meeting

Logos Solid - Free

Chat Meeting Application Slack

Chat Meeting Application

Sharp Line

Plump Gradient - Free

Sharp Pop

Flex Pop

Flex Gradient

Plump Pop - Free

Plump Neon

Sharp Remix

Core Pop - Free

Flex Neon

Plump Gradient

Flex Remix

Core Pop

Core Neon - Free

Plump Pop

Plump Remix - Free

Rounded Line - Streamline Material

Slack Channel

Communication

Sharp Line - Streamline Material

<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>

**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

---

## 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

---

## Brand & Cultural Identity

### What it communicates

> "We are refined and in motion."

---

## 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.

---

## 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

Slack Logo icon - Flex Line Set

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