Base64 File Decoder
Decode base64 strings back to downloadable files.
About this tool
Base64 file decoding is a crucial operation for developers, designers, and technical professionals who work with encoded data. When binary files—images, PDFs, archives, or documents—are converted to base64 text format, they become portable and easy to transmit via APIs, emails, or store directly in JSON databases. This tool exists to reverse that process quickly and conveniently, letting you download the original file from its encoded representation without requiring terminal commands or complex programming knowledge.
In practice, you'll encounter base64-encoded files in many scenarios: web APIs that return images or documents as base64 strings, data URLs embedded in HTML or CSS for embedding small assets, email attachments encoded in MIME messages, or blockchain applications and databases that store binary data as base64. The workflow is straightforward—paste your base64 string (or data URL), choose the correct file type from the MIME dropdown, name your file, and download it immediately. The tool handles the decoding in your browser entirely, so your data never leaves your device.
Whether you're extracting an image from a JSON API response, recovering a file from a data URL, or debugging encoded content in a database, this tool eliminates friction from a common technical task. It's designed for both occasional users who encounter base64 once in a blue moon and professionals who work with encoded files regularly—providing a fast, reliable alternative to online converters or manual decoding scripts.
Frequently Asked Questions
Code Implementation
import base64
def decode_base64_file(b64_string: str, output_path: str) -> None:
"""Decode a base64 string (with or without data URL prefix) and write to file."""
# Strip data URL prefix if present: data:image/png;base64,...
if "," in b64_string:
b64_string = b64_string.split(",", 1)[1]
# Remove whitespace
b64_string = b64_string.strip().replace("\n", "").replace("\r", "")
data = base64.b64decode(b64_string)
with open(output_path, "wb") as f:
f.write(data)
print(f"Decoded {len(data)} bytes → {output_path}")
# Encode a file to base64
def encode_file_to_base64(path: str) -> str:
with open(path, "rb") as f:
return base64.b64encode(f.read()).decode("utf-8")
# Round-trip example
encoded = encode_file_to_base64("example.png")
decode_base64_file(encoded, "decoded_example.png")
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