Image compression API

Re-encode smaller in the same format. Put a quality from 1 to 100 in "option".

When to call it

Image weight is the usual reason a page is slow, and the usual reason it stays slow is that compressing by hand does not survive contact with a content team. Putting it in the upload path applies the same setting to every file, forever.

For a one-off, the browser version needs no token and never sends your data anywhere: it runs on your own machine.

Example

curl -X POST https://astralbatch.com/api/v1/image-compress \
  -H "Authorization: Bearer ast_YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"input": "/9j/4AAQSkZJRgABAQAA...", "option": "70"}'

{
  "tool": "image-compress",
  "result": "/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAoHBwgHBgoICAgLCgoL...",
  "chars": 41260,
  "ms": 132
}

In your language

const res = await fetch("https://astralbatch.com/api/v1/image-compress", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.ASTRAL_TOKEN}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({"input": "/9j/4AAQSkZJRgABAQAA...", "option": "70"}),
});
if (!res.ok) throw new Error((await res.json()).detail);
const { result } = await res.json();

import os, requests

res = requests.post(
    "https://astralbatch.com/api/v1/image-compress",
    headers={"Authorization": f"Bearer {os.environ['ASTRAL_TOKEN']}"},
    json={"input": "/9j/4AAQSkZJRgABAQAA...", "option": "70"},
    timeout=30,
)
res.raise_for_status()
result = res.json()["result"]

Parameters

Errors

Errors are RFC 7807 problem documents with a stable type you can branch on.

Questions

What quality should I use?

Between 70 and 80 is usually invisible on a photograph and saves a great deal. Below 50 shows on flat colours and gradients. Test with your own images rather than trusting a number.

Does the format change?

No. A JPEG comes back a JPEG. JPEG uses mozjpeg, PNG is quantised to a palette at maximum effort, and WebP and AVIF re-encode at the quality you asked for.

Why did my PNG barely shrink?

PNG is lossless, so there is no quality dial: what it can drop is palette size. A photograph stored as PNG is better converted to WebP or AVIF than compressed as PNG.

Other endpoints

• Image metadata API
• Image resize API
• Image format converter API
• Batch rename API