Base64 vs Binary: When to Use Each
Compare base64 and raw binary encoding for data storage, API transmission, and embedded content.
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Base64 vs Binary: When to Use Each Part of our complete guide to this topic — see the full series. Raw binary is efficient; base64 is universal. The right choice depends on the channel, the data format, and whether you control both ends. --- All the tools discussed here are available for free at theproductguy.in — client-side, no sign-up required. What Is Base64? Base64 encodes arbitrary bytes into a string using 64 printable ASCII characters: A–Z, a–z, 0–9, , and , with for padding. The algorithm processes 3 bytes at a time: Take 3 bytes = 24 bits Split into 4 groups of 6 bits Map each 6-bit value (0–63) to the base64 alphabet The string encodes to . --- Why Base64 Exists: The Text-Only Problem? Many protocols were designed for ASCII text only: SMTP (email): 7-bit ASCII; the 8th bit can…
Frequently Asked Questions
What is the difference between base64 and binary?
Binary is the raw representation of data as bytes (0s and 1s). Base64 is an encoding that converts arbitrary bytes into a text string using 64 printable ASCII characters. Base64 is used when binary data needs to be transported through text-only channels (like email or JSON). Raw binary is more efficient for storage and binary-safe channels.
When should I use base64 vs binary in an API?
Use raw binary for REST APIs that handle file uploads via multipart/form-data or binary bodies — it is ~33% more efficient. Use base64 when embedding binary data inside JSON (since JSON is text), in GraphQL mutations, when passing data as query parameters, or when the API documentation specifies base64. Most HTTP/2 transfers handle binary natively, making base64 unnecessary for direct transfers.
Why does base64 increase data size by 33%?
Base64 encodes every 3 bytes as 4 characters. Each base64 character represents 6 bits of data (2^6 = 64). Three bytes = 24 bits = 4 groups of 6 bits. The output is 4/3 times the input size — approximately 33% larger. Padding with '=' characters brings the output length to a multiple of 4. For input sizes that are multiples of 3, there is no padding; otherwise 1 or 2 padding characters are added.
What is the overhead of base64 encoding?
Base64 adds approximately 33% to the data size due to the 4/3 byte-to-character ratio, plus up to 2 bytes of '=' padding. Additionally, base64 strings are often transmitted with line breaks every 76 characters (MIME requirement), adding ~2 bytes per 76 characters. In practice, expect 33–37% overhead. Compression before base64 encoding can often offset this.
When is raw binary preferred over base64?
Use raw binary when the transport layer supports it natively: file I/O, binary database columns (BYTEA, BLOB), HTTP with Content-Type: application/octet-stream, WebSocket binary frames, gRPC, and Protocol Buffers. These all handle arbitrary bytes without needing a text encoding layer, and binary is always more space-efficient than base64.
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