The Hidden Cost of Base64
Base64 was never designed for data storage or high-volume file transfers.
Its original purpose was to move binary data through systems that only understood plain text.
When you use it for large payloads today, you end up paying three major taxes.
1. The 33% Size Tax
Base64 encodes every 3 bytes of binary data as 4 ASCII characters.
The result is a ~33% increase in size, every single time.
A 100 MB video suddenly becomes 133 MB of text:
more bandwidth consumed
more time spent uploading
more storage wasted
All for zero functional benefit.
2. The Memory Bottleneck
Most Base64 encoders and decoders require the entire payload to be loaded into memory.
That means a 500 MB upload can easily cause:
1 GB RAM spikes
garbage collection pressure
process crashes under load
One large request can bring an otherwise healthy server to its knees.
3. The CPU Overhead
Encoding and decoding Base64 is not free.
Your CPU must:
parse large strings
convert them back to binary
allocate new buffers
All of this adds latency, increases response times, and reduces overall throughput—especially under concurrent load.
3 Better Alternatives for Large Files
If you’re building a scalable, production-grade system, stop treating files as strings.
Modern architectures are binary-first.
Here are three proven approaches.
1. The Cloud-Direct Pattern (Presigned URLs)
Your API should not be a middleman for raw bytes.
Instead of:
Client → API → Object Storage
Use presigned URLs.
How it works
The client asks your API for permission.
Your API returns a short-lived, secure upload URL from providers like AWS S3 or Google Cloud Storage.
The client uploads the file directly to the cloud.
Why it wins
Zero file data touches your server
No memory spikes
No CPU overhead
Massive scalability for free
Your backend stays fast and boring. Exactly how it should be.
II. Chunked & Resumable Uploads (TUS Protocol)
Uploading a 2 GB file in a single request is a gamble.
If the connection drops at 99%, the user starts over—and hates you for it.
How it works
Split the file into small chunks (e.g. 5 MB).
Upload them sequentially using a resumable protocol like TUS.
Why it wins
Fault-tolerant by design
Uploads can resume after failures
Ideal for unstable networks and large files
This is the standard for serious upload workflows.3. Binary Streaming
Sometimes you do need the file on your server—virus scanning, media processing, transformations.
In that case, stream it.
How it works
Use multipart/form-data and process the incoming request as a stream.
Pipe the data chunk-by-chunk directly to disk, cloud storage, or a processing pipeline.
Why it wins
Constant, predictable memory usage
Works with arbitrarily large files
Plays nicely with backpressure
Streams are how servers are meant to handle data.
Base64 is fine for:
small icons
tiny blobs
email attachments
But for large files, it’s pure technical debt.
If you want faster uploads, lower costs, and servers that don’t fall over when someone uploads a 4K video, move to presigned URLs, chunked uploads, or streaming.