Base64 Encoder & Decoder
Encode text to Base64 or decode Base64 strings back to text. File encoding supported.
Base64 Encoding: Why APIs and Web Use It
Base64 encoding converts binary data (images, files, binary strings) into a text-safe format using 64 ASCII characters. It is used everywhere: HTTP Basic Auth headers (Authorization: Basic base64(user:password)), embedding images directly in HTML/CSS (data:image/png;base64,...), storing binary data in JSON payloads, JWT tokens and email attachments (MIME encoding). Decoding is equally important — reading JWT payloads, debugging API auth headers and processing data URIs.
Frequently Asked Questions
Why is Base64 used in APIs and web development? ▼
Base64 solves the problem of transmitting binary data over text-only channels. HTTP headers, JSON and XML are text protocols that cannot carry raw binary. Base64 encodes binary into printable ASCII characters that travel safely through any text protocol. The trade-off: Base64 increases data size by ~33%.
How to decode a Base64 JWT token? ▼
A JWT has 3 parts separated by dots: header.payload.signature. Each part is Base64URL-encoded. Paste the payload section (middle part) into our decoder to see the claims (user ID, role, expiry etc.). Note: this only decodes — it does not verify the signature. Use jwt.io for full JWT inspection.
What is the difference between Base64 and Base64URL? ▼
Standard Base64 uses + and / which have special meaning in URLs. Base64URL replaces + with - and / with _ and omits trailing = padding. Base64URL is used in JWTs, OAuth tokens, safe file names and URL parameters. Our encoder has a "URL-Safe Encode" button that produces Base64URL format.
How to convert an image to Base64 for embedding in HTML? ▼
Use the File to Base64 section — upload any image. Copy the full data URL (data:image/png;base64,...). Use it directly as an img src: 
. This embeds the image in the HTML — useful for email templates and offline HTML documents that cannot reference external image URLs.
. This embeds the image in the HTML — useful for email templates and offline HTML documents that cannot reference external image URLs.Does Base64 provide encryption or security? ▼
No. Base64 is encoding, not encryption — anyone can decode it instantly. Do not use Base64 to "hide" sensitive data. It is only for safe text representation of binary data. For actual security, use AES-256 encryption or HTTPS/TLS.