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WebP to JPEG API#

The WebP to JPEG API converts a WebP image to JPEG format with a single request to POST /v1/convert/webp-to-jpeg. Upload a .webp file as multipart/form-data and receive raw JPEG bytes back, or set direct_download=false to get JSON metadata with a presigned download URL instead. Because JPEG does not support transparency, transparent areas in the WebP are composited onto a white background.

Endpoint#

POST /v1/convert/webp-to-jpeg

Content-Type: multipart/form-data

Accepted input: .webp files

Output format: .jpeg (image/jpeg)

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 `.webp` image file to convert.
`output_filename`	`string`	No	Input filename	Custom output filename. The `.jpeg` 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
If the WebP has an alpha channel (RGBA), transparent areas are composited onto a white background
Output quality is set to maximum (100)

Transparency note: JPEG does not support transparency. Any transparent areas in your WebP will appear white in the JPEG output.

Response#

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

HTTP 200 OK
Content-Type: image/jpeg
Content-Disposition: inline; filename="image_20260405_123456789.jpeg"

Returns raw image bytes.

Metadata Response (`direct_download=false`)#

{
    "presigned_url": "https://spaces.example.com/...",
    "object_key": "env/files/{project_id}/webp-to-jpeg/image_20260405_123456789.jpeg",
    "filename": "image_20260405_123456789.jpeg",
    "file_size": 45678,
    "conversion_time_seconds": 0.5
}

Code Examples#

Python#

import requests

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

with open("image_20260405_123456789.jpeg", "wb") as out:
    out.write(response.content)

Node.js#

const form = new FormData();
form.append("file", fs.createReadStream("image.webp"));

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

fs.writeFileSync("image_20260405_123456789.jpeg", Buffer.from(await response.arrayBuffer()));

PHP#

$ch = curl_init("https://api.enconvert.com/v1/convert/webp-to-jpeg");
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => ["X-API-Key: sk_your_private_key"],
    CURLOPT_POSTFIELDS => ["file" => new CURLFile("image.webp")]
]);
$output = curl_exec($ch);
curl_close($ch);
file_put_contents("image_20260405_123456789.jpeg", $output);

Go#

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

req, _ := http.NewRequest("POST", "https://api.enconvert.com/v1/convert/webp-to-jpeg", 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 `.webp` 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 WebP to JPEG with a REST API?#

Send a POST request to /v1/convert/webp-to-jpeg with your .webp file in a multipart/form-data body and authenticate with an X-API-Key header or a JWT Authorization: Bearer token. The API returns the converted JPEG as raw image bytes by default.

What happens to transparency when converting WebP to JPEG?#

JPEG does not support transparency, so if the WebP has an alpha channel (RGBA), transparent areas are composited onto a white background in the JPEG output.

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

Yes. Set direct_download=false and the API returns JSON metadata including a presigned_url, filename, file_size, and conversion_time_seconds instead of the raw bytes.

Why does the WebP to JPEG API return 402 Payment Required?#

A 402 Payment Required response means your monthly ops allowance or storage limit has been reached for your plan.

What is the maximum WebP file size I can upload?#

Max file size is plan-dependent (5 MB on the Founding plan). Files exceeding your plan's limit are rejected with 413 Payload Too Large.

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API Documentation