Convert PNG to WebP
Turn PNG, the lossless web image format with full transparency support, into WebP, Google's modern web image format, smaller than JPEG or PNG. FileChanger runs the image conversion in one call, no local tooling to install.
In the browser
Upload a file and download the result, no pipeline required. Open the converter.
One API call
POST the file with from=png and to=webp, get the converted bytes back. Jump to the code.
From an agent
FileChanger ships an MCP server, so agents can run this conversion themselves. See the docs for setup.
Uploading something you care about? How to convert files safely explains what to check before you trust any converter, and Security and data handling describes exactly what we store and for how long.
Convert PNG to WebP in code
The same call from any language: POST the file to /api/convert, the response body is the converted file.
curl -X POST https://filechanger.io/api/convert \
-H "X-Api-Key: fc_your_api_key_here" \
-F "file=@input.png" \
-F "from=png" \
-F "to=webp" \
-o output.webpimport requests
with open("input.png", "rb") as f:
response = requests.post(
"https://filechanger.io/api/convert",
headers={"X-Api-Key": "fc_your_api_key_here"},
files={"file": f},
data={"from": "png", "to": "webp"},
)
response.raise_for_status()
with open("output.webp", "wb") as out:
out.write(response.content)const formData = new FormData();
formData.append("file", fileInput.files[0]);
formData.append("from", "png");
formData.append("to", "webp");
const response = await fetch("https://filechanger.io/api/convert", {
method: "POST",
headers: { "X-Api-Key": "fc_your_api_key_here" },
body: formData,
});
const output = await response.blob();import java.net.http.HttpRequest.BodyPublishers;
import java.net.http.HttpResponse.BodyHandlers;
import java.nio.file.Path;
String boundary = "----FormBoundary" + System.currentTimeMillis();
byte[] fileBytes = java.nio.file.Files.readAllBytes(Path.of("input.png"));
String body = "--" + boundary + "\r\n"
+ "Content-Disposition: form-data; name=\"file\"; filename=\"input.png\"\r\n"
+ "Content-Type: application/octet-stream\r\n\r\n"
+ new String(fileBytes) + "\r\n"
+ "--" + boundary + "\r\nContent-Disposition: form-data; name=\"from\"\r\n\r\npng\r\n"
+ "--" + boundary + "\r\nContent-Disposition: form-data; name=\"to\"\r\n\r\nwebp\r\n"
+ "--" + boundary + "--";
HttpClient client = HttpClient.newHttpClient();
HttpRequest request = HttpRequest.newBuilder()
.uri(URI.create("https://filechanger.io/api/convert"))
.header("X-Api-Key", "fc_your_api_key_here")
.header("Content-Type", "multipart/form-data; boundary=" + boundary)
.POST(BodyPublishers.ofString(body))
.build();
HttpResponse<byte[]> response = client.send(
request, BodyHandlers.ofByteArray());
java.nio.file.Files.write(Path.of("output.webp"), response.body());import Network.HTTP.Client
import Network.HTTP.Client.MultipartFormData
import qualified Data.ByteString.Lazy as BL
main :: IO ()
main = do
manager <- newManager defaultManagerSettings
initialReq <- parseRequest "POST https://filechanger.io/api/convert"
let req = initialReq
{ requestHeaders = [("X-Api-Key", "fc_your_api_key_here")] }
request <- formDataBody
[ partFileSource "file" "input.png"
, partBS "from" "png"
, partBS "to" "webp"
] req
response <- httpLbs request manager
BL.writeFile "output.webp" (responseBody response)About PNG
Portable Network Graphics (PNG) is an open, lossless raster image format featuring 24-bit RGB color and full alpha-channel transparency. It is the web standard for logos, diagrams, user interface assets, and screenshots where pixel sharpness and clean transparency edges are essential.
About WebP
WebP is Google's image format for the web, one codec covering what JPEG and PNG do separately: lossy and lossless compression, an alpha channel, and animation. Every current browser supports it, and it usually lands well under the size of an equivalent JPEG, which is why site builds and CDNs emit it by default.
Frequently asked questions
How do I convert PNG to WebP?
Upload your file in the browser converter and pick WebP as the target, or POST it to /api/convert with from=png and to=webp. The response body is the converted file.
Is converting PNG to WebP free?
Yes. Every account gets 200 MB of conversions free, metered on input size. After that you pay only for what you convert, from $0.10 per GB, with no monthly fee. See pricing for the paid tiers.
Is there an API for PNG to WebP conversion?
Yes, this whole conversion is one POST to /api/convert (the code examples above show it in five languages), plus an MCP server so AI agents can run it directly.
How much file size reduction can I expect converting PNG to WebP?
WebP lossless compression is typically 26% smaller than standard PNGs, and lossy WebP can reduce transparent image file sizes by over 60% with minimal visual degradation.
Why convert PNG to WebP?
WebP is Google's modern image format for the web. It supports full alpha transparency while achieving substantially smaller file sizes than PNG, making pages load faster.
Does converting PNG to WebP preserve transparency?
Yes. WebP supports 8-bit alpha channel transparency just like PNG, so all transparent areas, translucent gradients, and anti-aliased edges are fully preserved.