Encode and decode Base64 for configs, attachments and debug sessions
APIs still ship identifiers, thumbnails and serialized blobs as Base64 when binary over JSON is awkward. Decoding by hand is error-prone; encoding a test fixture without padding breaks downstream parsers. This converter transforms text and small payloads entirely in the browser so tokens, certificates and webhook samples you are debugging never pass through a server-side upload endpoint. Use it when inspecting a data URL, preparing a unit test fixture or verifying what a mobile client actually sent.
Base64 workflow
- Paste plain text to encode or a Base64 string to decode.
- Confirm URL-safe versus standard alphabet if decoding fails.
- Copy the result into your test, config or ticket.
- Inspect structured tokens with the JWT Decoder when applicable.
Variants teams confuse
Standard Base64 uses plus and slash; URL-safe variants swap characters for query strings. PEM blocks include headers and line wraps — strip decoration before decoding raw payload bytes. UTF-8 text must round-trip through the correct character set; binary decoded as text shows mojibake. Very large strings may slow the tab because work is synchronous.
Related utilities
Pretty-print JSON discovered after decoding with the JSON Formatter and validate syntax in the JSON Validator. Compare hashes with the Hash Generator when you need digests instead of reversible encoding. For URL components, pair with the URL Encoder when plus signs and slashes need percent escaping in query parameters.
Security reminders
Never treat Base64 as protection for secrets. Redact bearer tokens before screen sharing even though decoding is local. Rotate credentials if they were pasted into a ticket attached to a screenshot. Prefer structured JWT tooling when you need exp, aud and alg fields interpreted, not just decoded bytes.
Binary data and size limits
Very large pasted strings can slow the tab because encoding is synchronous. For multi-megabyte blobs, prefer streaming tools in your pipeline. Remember that Base64 expands size by roughly four thirds — plan transport limits accordingly. When decoding fails, check for missing padding characters and URL-safe alphabets that use hyphens instead of plus signs. For JWT segments, decode with the dedicated JWT tool after you extract the middle part so you do not confuse padding with signature material.
Choosing encode versus hash
Base64 is reversible encoding, not a digest. When you need to verify integrity or store passwords, use the Hash Generator instead. When you need to move binary through JSON or email, Base64 is appropriate. If the output must stay secret in transit, add TLS and access controls — encoding alone does not provide confidentiality.