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JPEG to PNG API#

Convert JPEG images to PNG programmatically with POST /v1/convert/jpeg-to-png. The endpoint accepts a .jpeg or .jpg upload and produces a lossless PNG with full color fidelity. Responses return either raw image bytes for direct download or JSON metadata with a presigned download URL.

Endpoint#

POST /v1/convert/jpeg-to-png

Content-Type: multipart/form-data

Accepted input: .jpeg or .jpg files

Output format: .png (image/png)

Authentication#

Requires either a private API key or a JWT token from a public key.

X-API-Key: sk_your_private_key

Or:

Authorization: Bearer <jwt_token>

Request Parameters#

Parameter	Type	Required	Default	Description
`file`	file	Yes	--	The `.jpeg or .jpg` image file to convert.
`output_filename`	`string`	No	Input filename	Custom output filename. The `.png` extension is added automatically.
`direct_download`	`boolean`	No	`true`	When `true`, returns raw image bytes. When `false`, returns JSON metadata with a presigned download URL.

Conversion Details#

Uses Pillow for direct format conversion
JPEG's RGB color data is preserved losslessly in the PNG output
PNG output uses lossless compression
Output quality is maximum (lossless)

Response#

Direct Download (`direct_download=true`, default)#

HTTP 200 OK
Content-Type: image/png
Content-Disposition: inline; filename="photo_20260405_123456789.png"

Returns raw image bytes.

Metadata Response (`direct_download=false`)#

{
    "presigned_url": "https://spaces.example.com/...",
    "object_key": "env/files/{project_id}/jpeg-to-png/photo_20260405_123456789.png",
    "filename": "photo_20260405_123456789.png",
    "file_size": 45678,
    "conversion_time_seconds": 0.5
}

Code Examples#

Python#

import requests

with open("photo.jpg", "rb") as f:
    response = requests.post(
        "https://api.enconvert.com/v1/convert/jpeg-to-png",
        headers={"X-API-Key": "sk_your_private_key"},
        files={"file": ("photo.jpg", f)}
    )

with open("photo_20260405_123456789.png", "wb") as out:
    out.write(response.content)

Node.js#

const form = new FormData();
form.append("file", fs.createReadStream("photo.jpg"));

const response = await fetch("https://api.enconvert.com/v1/convert/jpeg-to-png", {
    method: "POST",
    headers: { "X-API-Key": "sk_your_private_key" },
    body: form
});

fs.writeFileSync("photo_20260405_123456789.png", Buffer.from(await response.arrayBuffer()));

PHP#

$ch = curl_init("https://api.enconvert.com/v1/convert/jpeg-to-png");
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => ["X-API-Key: sk_your_private_key"],
    CURLOPT_POSTFIELDS => ["file" => new CURLFile("photo.jpg")]
]);
$output = curl_exec($ch);
curl_close($ch);
file_put_contents("photo_20260405_123456789.png", $output);

Go#

body := &bytes.Buffer{}
writer := multipart.NewWriter(body)
part, _ := writer.CreateFormFile("file", "photo.jpg")
file, _ := os.Open("photo.jpg")
io.Copy(part, file)
writer.Close()

req, _ := http.NewRequest("POST", "https://api.enconvert.com/v1/convert/jpeg-to-png", body)
req.Header.Set("Content-Type", writer.FormDataContentType())
req.Header.Set("X-API-Key", "sk_your_private_key")
resp, _ := http.DefaultClient.Do(req)

Error Responses#

Status	Condition
`400 Bad Request`	File is not a `.jpeg or .jpg` file
`400 Bad Request`	Image conversion failed (corrupt or unsupported file)
`401 Unauthorized`	Missing or invalid API key / JWT token
`402 Payment Required`	Monthly ops allowance exhausted
`402 Payment Required`	Storage limit reached
`413 Payload Too Large`	File exceeds plan's maximum file size

Limits#

Limit	Value
Max file size	Plan-dependent (Founding: 5 MB)
Output quality	Maximum (not configurable)
Monthly conversions	Plan-dependent

Frequently asked questions#

How do I convert a JPG to PNG with a REST API?#

Send a multipart/form-data POST request to /v1/convert/jpeg-to-png with your .jpeg or .jpg file in the file field, authenticated via X-API-Key or a Bearer JWT token. By default the API responds with the raw PNG bytes.

Is JPEG to PNG conversion lossless?#

Yes. The JPEG's RGB color data is preserved losslessly in the PNG output, and the PNG itself uses lossless compression at maximum quality.

Can I get a download URL instead of raw image bytes?#

Yes. Set direct_download=false and the API returns JSON metadata including a presigned_url, object_key, filename, file_size, and conversion_time_seconds.

Why does the API return 402 Payment Required?#

A 402 means your plan's monthly ops allowance or storage limit has been reached. Files exceeding your plan's maximum file size return 413 Payload Too Large instead.

← Images png-to-jpeg →

API Documentation