Tool usage guide

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Category: Development
Input types: file, select, text
Output type: text
Sample coverage: 4
API ready: Yes

Overview

The Data URI Generator converts local files like images, fonts, and stylesheets into encoded Data URIs using Base64 or percent-encoding. This allows developers to inline assets directly into HTML, CSS, or Markdown documents, reducing HTTP requests and simplifying asset delivery.

When to use

When you want to embed small icons, logos, or fonts directly into CSS or HTML to eliminate extra HTTP requests.
When creating self-contained HTML templates, email newsletters, or Markdown files that need to display images without external hosting.
When developing offline-first web applications or single-file prototypes that require embedded assets.

How it works

1Upload your file (such as PNG, SVG, WOFF2, or MP3) using the file input.
2Select your preferred encoding method (Base64, URL-encoded, or Raw) and output format (Data URI, HTML img tag, CSS background, or Markdown).
3Optionally override the automatically detected MIME type if a custom type is required.
4Copy the generated Data URI or formatted code snippet directly into your project.

Use cases

Inlining SVG icons directly into CSS background-image properties to keep stylesheets self-contained.
Embedding custom web fonts (WOFF2) inside a CSS @font-face rule to prevent layout shifts during loading.
Inserting small images directly into Markdown documentation or README files without relying on external image hosting.

Examples

1. Embedding a UI Icon in CSS

Frontend Developer

Background

A developer is building a lightweight UI library and wants to include a search icon directly inside the CSS file to avoid external asset dependencies.

Problem

The icon needs to load instantly with the stylesheet without triggering an additional network request.

How to use

Upload the search-icon.svg file, select 'Base64' encoding, and set the output format to 'CSS background'.

Encoding: Base64, Output format: CSS background

Outcome

Generates a CSS rule: background-image: url("data:image/svg+xml;base64,..."); ready to paste into the stylesheet.

2. Inlining a Logo in an Email Template

Email Marketer

Background

An email marketer is designing an HTML newsletter and wants to ensure the company logo displays even if the recipient's email client blocks external images.

Problem

External image URLs are frequently blocked or load slowly in email clients.

How to use

Upload the logo.png file, select 'Base64' encoding, and choose 'HTML <img> tag' as the output format.

FAQ

What file types are supported by the generator?

The generator supports images (PNG, JPEG, SVG, WebP), fonts (WOFF, WOFF2, TTF), audio, video, PDFs, and text files (CSS, JS, HTML, JSON).

Does using Data URIs improve website performance?

It reduces HTTP requests, which benefits small assets like icons. However, Base64 encoding increases file size by about 33%, so it is not recommended for large files.

Can I customize the MIME type of the output?

Yes, you can manually override the auto-detected MIME type using the custom MIME type input field.

What is the difference between Base64 and URL-encoding?

Base64 is standard for binary files like images and fonts, while URL-encoding (percent-encoding) is ideal for text-based assets like SVGs to keep them readable and slightly smaller.

Is there a file size limit for uploads?

Yes, the tool supports files up to 10 MB in size.

Encoding: Base64, Output format: HTML <img> tag

Data URI Generator

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Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Embedding a UI Icon in CSS

2. Inlining a Logo in an Email Template

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