---
seo_title: JPEG to PNG API: Convert JPG to PNG in Code | EnConvert
meta_desc: Convert JPEG to PNG with a REST API. POST /v1/convert/jpeg-to-png returns a lossless PNG as raw bytes or a presigned URL. Python, Node, PHP, Go examples.
keywords: jpeg to png api, jpg to png api, convert jpeg to png programmatically, jpg to png converter api, png conversion rest api, convert jpg to png python, image format conversion api
---

# 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`)

```json
{
    "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

```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

```javascript
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

```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

```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.