SVG Blob Generator

About SVG Blob Generator

How Does the Blob Generator Work?

The algorithm places a configurable number of points (3 to 20) at equal angles around a circle. Each point is then nudged outward or inward by a random amount controlled by the randomness slider. The displaced points are connected using the SVG cubic bezier curve command (C), which takes two control points and an endpoint to produce a smooth path segment. The control points are calculated from the positions of neighbouring anchors, so the final outline flows naturally without sharp corners. The W3C SVG specification defines the C command as part of the path element, supported by every modern browser with a compatibility score of 100% according to Can I Use.

Worked example: Set complexity to 6 and randomness to 50%. The generator places 6 points at 60-degree intervals (360/6). Each point sits on a circle of radius 140 px (for a 300 px canvas). A randomness of 50% means each radius is multiplied by a factor between roughly 0.5 and 1.5, so individual points land anywhere from 70 px to 210 px from the centre. The bezier control points are derived from the difference between adjacent point positions divided by 4, which keeps the curve smooth. The result is a path string like M 290.0 150.0 C 270.1 198.3, 218.4 255.0, 150.0 280.0 ... that the browser renders as a closed shape.

Customisation Options

Control	Range	Effect
Complexity (points)	3-20	Fewer points produce smoother, rounder shapes. More points create detailed, irregular edges
Randomness	0-100%	0% gives a perfect circle. 100% produces wild, asymmetric outlines
Canvas size	100-600 px	Sets the SVG viewBox dimensions. Larger canvases give more room for detail
Blob count	1-5	Layer multiple blobs with varying opacity for depth
Colour mode	Solid or gradient	Solid fill or a two-stop linear gradient from top-left to bottom-right
Randomise colours	One-click button	Picks a new random colour scheme using cryptographically random values

When using multiple blobs, opacity scales from 0.6 for the first blob up to 1.0 for the last, creating a natural sense of depth where front layers appear more solid.

Recommended Settings by Use Case

Use Case	Complexity	Randomness	Blobs	Colour
Background decoration	5-8	30-50%	2-3 layered	Soft gradient, low opacity
Hero section accent	6-10	40-60%	1-2	Brand gradient
Button or card background	4-6	20-40%	1	Solid brand colour, low opacity
Social media graphic	8-12	50-70%	1	Bold gradient
Presentation slide	5-7	30-50%	1-2	Match slide theme
Abstract art / experiment	15-20	80-100%	3-5	Random colours, mixed opacity

For hero sections, a complexity of 6-8 with 40-50% randomness is a good starting point. It produces shapes that look organic without becoming chaotic. Increase blob count to 2 and enable gradients for a layered, modern look that suits SaaS landing pages and portfolio sites.

Why SVG Instead of PNG or JPEG?

Over 65% of all websites use SVG as of 2026, according to W3Techs, up from 63.3% the year before. The format is popular for good reason. SVG is a text-based vector format defined by the W3C, first released as a recommendation in 2001 and now in its second major version (SVG 2, Candidate Recommendation since 2018). Because the output is XML text rather than a pixel grid, a typical blob SVG weighs under 1 KB. The same shape exported as a PNG at 600 px would be 50-200 KB depending on colour complexity. Studies from VectoSolve show SVG can save 60-80% of network bandwidth compared to equivalent PNG assets, and the savings compound on retina displays where PNG needs @2x and @3x variants while SVG needs just one file.

Feature	SVG	PNG
Typical blob file size	0.5-1 KB	50-200 KB
Retina support	Single file, infinite scale	Needs @2x/@3x variants
Gzip compression	Compresses 70-80% (text-based)	Already compressed, minimal gain
CSS customisation	Change fill, stroke, opacity in CSS	Must regenerate the image
Animation	Path morphing via CSS or JS	Requires sprite sheets or GIF
Browser support	100% of modern browsers	100% of modern browsers

Using Blobs in Web Projects

Once you have your SVG code, there are several ways to integrate blob shapes into a website or design project.

Technique	How
Background accent	Position the blob with CSS absolute positioning behind content sections. Set opacity to 0.1-0.3 for a subtle effect
Image mask	Use the blob path as a CSS clip-path to crop photos into organic shapes. See the clip-path generator for more complex masks
Layered composition	Stack 2-3 blobs with different colours and opacity values for depth
Animated background	Define two blob paths as CSS keyframes and transition between them using the d property or JavaScript path interpolation
Section divider	Place a wide, low-randomness blob where sections meet instead of a horizontal line

CSS example for background placement: Set the blob's container to position: absolute; top: -100px; right: -50px; z-index: -1; opacity: 0.15; and the blob will sit behind your content as a decorative accent. Because SVG is vector-based, the same shape works at any viewport width without quality loss.

Understanding SVG Path Syntax

The code preview panel shows the raw SVG markup. The key part is the d attribute on the <path> element. It uses these commands, defined in the W3C SVG path specification:

Command	Name	Parameters	What It Does
M	Move To	x y	Moves the pen to a starting position without drawing
C	Cubic Bezier	x1 y1, x2 y2, x y	Draws a curve using two control points (x1,y1 and x2,y2) to an endpoint (x,y)
Z	Close Path	none	Draws a straight line back to the starting point

This generator uses only the M, C, and Z commands. The cubic bezier (C) is the most important one - it takes two control points that act like magnets, pulling the curve toward them. By calculating control points from neighbouring anchor positions, the algorithm ensures smooth transitions between segments. The MDN Web Docs SVG Paths tutorial provides a detailed interactive walkthrough of all path commands.

Export Options

Format	How to Use	Best For
Copy SVG code	Paste directly into HTML. The SVG is self-contained with no external dependencies	Web development, inline SVG, email templates
Download .svg file	Import into Figma, Sketch, Illustrator, Canva, or any vector editor	Design tools, presentations, print projects

When using gradient fills, the SVG includes a <linearGradient> definition inside a <defs> block. This is standard SVG and works in all modern browsers, design tools, and most email clients that support SVG.

Common Mistakes When Using SVG Blobs

Blob shapes are simple to generate but easy to misuse. Here are the most frequent problems and how to avoid them.

Too many blobs at once. Layering 4-5 high-complexity blobs with full opacity creates visual noise rather than depth. Stick to 2-3 blobs maximum for backgrounds, and keep opacity between 0.1 and 0.3 for decorative elements. The strongest blob compositions use one dominant shape and one or two supporting shapes at lower opacity.

Randomness set too high. At 80-100% randomness, blobs lose their organic feel and start looking like random splatters. For most design work, 30-60% randomness produces the most appealing shapes. Reserve high randomness for abstract art or experimental compositions where unpredictability is the goal.

Ignoring the viewBox. The SVG output includes a viewBox attribute that defines the coordinate system. When you paste the SVG into HTML, you can set the displayed size with CSS (width: 100%; max-width: 400px;) without changing the viewBox. The shape scales proportionally. A common mistake is setting explicit width and height attributes in pixels, which prevents the SVG from being responsive.

Not compressing the SVG. While blob SVGs are already small (typically under 1 KB), you can reduce the code further by running it through an SVG optimiser like SVGO. This strips unnecessary whitespace, shortens path coordinates, and removes default attributes. For blobs with gradients, the savings are usually 20-30% of the original size.

Missing alt text. When embedding the SVG as an <img> tag, always include a descriptive alt attribute. For decorative blobs, use alt="" with an empty string to tell screen readers to skip it. For meaningful blobs (like a logo mask), describe what the image represents.

Animating SVG Blobs with CSS

One of the most popular uses for blob shapes is animated morphing backgrounds. The basic approach is to generate two different blob paths and animate between them. Modern browsers support animating the SVG d attribute directly via CSS, though browser support for this is still evolving. The more reliable method uses JavaScript libraries like GSAP or Flubber that interpolate between path strings.

A simple CSS approach for a pulsing effect works without changing the path at all:

@keyframes pulse { 0%, 100% { transform: scale(1); } 50% { transform: scale(1.05); } }

Apply this to the SVG element with animation: pulse 4s ease-in-out infinite; for a gentle breathing effect. Combine with filter: blur(40px); for a soft, glowing background blob that feels alive without heavy JavaScript.

For true path morphing, generate two blobs with the same complexity setting (so they have the same number of points), copy both path strings, and use CSS or JS to transition between the two d values. The equal point count ensures the browser can smoothly interpolate between shapes without artifacts.

For repeating geometric patterns, try the SVG pattern generator. For pure CSS backgrounds without SVG, the CSS gradient generator creates linear, radial, and conic gradients. To build a full colour scheme for your blob, the colour palette generator can help pick harmonious combinations.

Sources

• W3Techs - Usage Statistics of SVG for Websites
• Can I Use - SVG Browser Support
• W3C - SVG 2 Path Specification
• MDN Web Docs - SVG Paths Tutorial
• VectoSolve - PNG vs SVG for Web Performance