Each pattern below maps to a real workflow. Use the linked tools when you need to encode, decode, or validate output before shipping.

1. 1

   Embedding images in HTML and CSS

   Convert small icons or logos to Base64 data URIs so they load without extra HTTP requests. Best for tiny assets—large images bloat your bundle.

   Image to Base64 →

2. 2

   API and JSON data transmission

   REST and GraphQL APIs often expect file bytes as a Base64 string inside JSON when multipart uploads are not available.

   JSON Validator →

3. 3

   Data URL creation

   Build data:image/png;base64,… URLs to inline resources in HTML, CSS, or canvas workflows.

4. 4

   Email attachments

   SMTP and many email APIs require MIME parts with Base64-encoded attachment bodies—common in transactional email pipelines.

5. 5

   Configuration and deployment files

   Store certificates, keys, or small binary blobs in YAML, JSON, or environment variables as Base64 text—still treat decoded values as secrets.

6. 6

   Web storage and cookies

   localStorage, sessionStorage, and cookies only store strings. Base64 lets you persist binary or structured blobs safely as text.

7. 7

   Debugging and testing

   Decode strings from logs, webhooks, or network tabs to inspect JWT segments, API payloads, or mis-encoded data during incidents.

   JWT Decoder →

• Format conversion only — use when the channel requires text
• Watch size — ~33% overhead; avoid multi-megabyte data URIs
• Validate before decode — reject malformed padding from untrusted sources
• Handle errors — wrap decode in try/catch in production code
• Prefer multipart — for large uploads when HTTP allows it

Browser APIs are fine for ASCII; UTF-8 strings often need extra handling or a dedicated tool.

// Encoding (ASCII-safe strings)
const encoded = btoa("Hello World");
// "SGVsbG8gV29ybGQ="

// Decoding
const decoded = atob("SGVsbG8gV29ybGQ=");
// "Hello World"

// UTF-8: use TextEncoder + bytes, or our Base64 tool