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pdfconversionapi

RTF to WebP API

POST an .rtf file to /v2/convert/rtf/to/webp and get a lossless WebP for every page. The sample asks for images 900 pixels tall and gets two 695 × 900 pages of 67,096 and 25,758 bytes.

Endpoint
POST /v2/convert/rtf/to/webp
Accepts
rtf
Sample timing
37 ms median of 5 runsHow we measure
Request size
Up to 10 MB on the Free plan or 100 MB on paid plans, all files together

Request and response

Every sample below ran against the API before this page was published. Set PDFCONVERSIONAPI_KEY to your key and run it as is.

curl -sS -X POST \
  https://api.pdfconversionapi.com/v2/convert/rtf/to/webp \
  -H "Authorization: Bearer $PDFCONVERSIONAPI_KEY" \
  -F File=@repair-estimate.rtf \
  --form-string ImageHeight=900 \
  -o response.json

# FileData is base64. Save the first file in converted/,
# or print the JSON error.
if jq -e '.Files' response.json > /dev/null; then
  mkdir -p converted
  name=$(jq -r '.Files[0].FileName' response.json)
  jq -r '.Files[0].FileData' response.json \
    | base64 --decode > "converted/$name"
else
  cat response.json
fi
200 OK37 ms median2 files, 91 KB
{
  "ConversionCost": 1,
  "ConversionTime": 0.037,
  "Files": [
    {
      "FileName": "repair-estimate-1.webp",
      "FileExt": "webp",
      "FileSize": 67096,
      "FileData": "UklGRhAGAQBXRUJQVlA4TAQG…"
    },
    {
      "FileName": "repair-estimate-2.webp",
      "FileExt": "webp",
      "FileSize": 25758,
      "FileData": "UklGRpZkAABXRUJQVlA4TIlk…"
    }
  ]
}

Response from our test run on 2026-11-03. ConversionTime shows the median of 5 runs. FileData is shortened here; the real response carries the whole file as base64.

The sample, converted

The same file the code sends. Download the input and the output and compare them yourself.

First page of repair-estimate-1.webp, rendered by the API
Input
repair-estimate.rtf (14 KB)
Output
repair-estimate-1.webp (66 KB)repair-estimate-2.webp (25 KB)
Source
A two-page repair estimate letter from a fictional appliance shop, with a logo, a priced table, lists, a link, a footnote and a page-numbered footer. We wrote it for these pages in Rich Text Format. (CC0-1.0). How it was made
Made by
2026-11-04, API build 9eeeb0640aba

Parameters

Send these as form fields next to the file. Names are case-insensitive. If you set one of the documented options below that we don't support yet, the request fails with a 400 that names it instead of returning a file made without it.

ParameterWhat it does
ImageHeightintegerHeight of each page image in pixels, as the sample sends. The width follows the Letter shape (900 tall gives 695 wide), and the page is drawn directly at that scale.Values: 1–20000
ImageWidthintegerWidth in pixels. With ImageHeight too, the page fits inside the box: 600 by 600 gave 464 × 600.Values: 1–20000
ScaleProportionsboolean, default truefalse stretches each page to exactly ImageWidth × ImageHeight; 600 by 900 then gives 600 × 900 images with distorted text.
ImageResolutioninteger, default 150Drawing DPI when you don't give a pixel size; nothing is stored in the file, because WebP has no resolution field. 150 makes the letter's pages 1,275 × 1,650 (137,520 and 55,616 bytes).Values: 36–600
PageRangestringDraw some pages only: last with ImageResolution=36 gave an 8,250-byte image of page 2.
TransparentColorstringOne exact color to make transparent, which adds an alpha channel to the otherwise RGB image. White also removes the white parts of pictures, such as the lettering in the sample's logo.Values: white, black, red, green, blue, gray, #RRGGBB or R,G,B
BackgroundColorstringPaint behind the page; it fills margins and areas with no fill of their own.Values: Same as TransparentColor
FileNamestringStem for the image files: FileName=estimate gives estimate-1.webp and estimate-2.webp.
StoreFileboolean, default falseReturn a link per page, valid for 3 hours, instead of base64.

What carries over, and what doesn't

Kept

  • Lossless pixels (VP8L), so the 8 pt header and the 10 pt table text keep clean edges
  • Only the channels the page needs: RGB, with alpha added when you send TransparentColor
  • The RTF's table geometry, colors and logo as laid out for the PDF route, header and footer included

Lost or not yet supported

  • Quality settings: the encoder is lossless only, so ImageQuality is ignored; size is set by the pixel dimensions.
  • A DPI value in the file.
  • The right page number on page 2 (it shows the stored "page 1 of 2") and the footnote.
  • The headings' bold weight and size: heading 1 (15 pt bold in the file) is drawn at 20 pt regular, heading 2 (12 pt bold) at 16 pt regular.

Limits

  • At most 2,000 pages per request; each page within 16,000 pixels per side and 100 million pixels.
  • Requests up to 10 MB on the Free plan or 100 MB on paid plans, all files and fields together; 120 seconds per conversion, then 504.

Where teams use it

Letter previews in a web app

Show customers the pages of an RTF estimate or letter in the browser. At 900 pixels tall, the sample's two pages are 92,854 bytes in all as WebP against 209,725 as PNG.

Fixed-height page strips

Send ImageHeight so every page of every document comes back the same height, which lines up in a horizontal strip or carousel.

Questions

How do WebP sizes compare with PNG and JPEG here?

At 900 pixels tall the sample's page 1 is 67,096 bytes as lossless WebP, 144,172 as PNG and 76,038 as JPEG at quality 75; page 2 is 25,758, 65,553 and 34,632. For these text pages the lossless WebP is the smallest of the three and the only one that is both small and exact.

Can I make the WebP lossy to save more space?

Not yet. Every WebP from this route is lossless and ImageQuality makes no difference. Reduce ImageHeight or ImageWidth, or use the JPG route with an ImageQuality you choose.

Why isn't the heading bold?

Bold and size set directly on an RTF heading paragraph are not applied, while its color and font are. The sample's 15 pt bold heading 1 is drawn at 20 pt regular in its blue Arial-compatible font.

Convert your first RTF file in a minute.