/// EDIT
FreeLinearize PDF API
Restructure a PDF so the first page displays before the rest of the file finishes downloading.
/// Quick answer
Linearize restructures a PDF's internal object layout so a viewer can render the first page before the rest of the file has downloaded — commonly called 'Fast Web View'. The output's linearization is verified before it's returned, reported in pdf-info's own linearized field.
How does the Linearize PDF API work?
One HTTP request from any language. Every ASHDOCS endpoint uses the same X-API-Key header.
curl -X POST https://www.ashdocs.com/api/v2/tools/pdf-linearize \ -H "X-API-Key: ash_live_..." \ -F "file=@document.pdf"
import requests
r = requests.post(
"https://www.ashdocs.com/api/v2/tools/pdf-linearize",
headers={"X-API-Key": "ash_live_..."},
files=[("file", open("document.pdf", "rb"))],
)
job = r.json()
print(job["status"], job.get("url"))import { readFile } from "node:fs/promises";
const form = new FormData();
form.append("file", new Blob([await readFile("document.pdf")]), "document.pdf");
const res = await fetch("https://www.ashdocs.com/api/v2/tools/pdf-linearize", {
method: "POST",
headers: { "X-API-Key": "ash_live_..." },
body: form,
});
const job = await res.json();
console.log(job.status, job.url);using var client = new HttpClient();
client.DefaultRequestHeaders.Add("X-API-Key", "ash_live_...");
using var form = new MultipartFormDataContent();
form.Add(new ByteArrayContent(await File.ReadAllBytesAsync("document.pdf")), "file", "document.pdf");
var res = await client.PostAsync("https://www.ashdocs.com/api/v2/tools/pdf-linearize", form);
var job = await res.Content.ReadAsStringAsync();
Console.WriteLine(job);import java.io.ByteArrayOutputStream;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
public class Sample {
static final String BOUNDARY = "AshdocsBoundary7MA4YWxkTrZu0gW";
public static void main(String[] args) throws Exception {
ByteArrayOutputStream body = new ByteArrayOutputStream();
addFile(body, "file", "document.pdf");
body.write(("--" + BOUNDARY + "--\r\n").getBytes(StandardCharsets.UTF_8));
HttpRequest req = HttpRequest.newBuilder(URI.create("https://www.ashdocs.com/api/v2/tools/pdf-linearize"))
.header("X-API-Key", "ash_live_...")
.header("Content-Type", "multipart/form-data; boundary=" + BOUNDARY)
.POST(HttpRequest.BodyPublishers.ofByteArray(body.toByteArray()))
.build();
HttpResponse<String> res = HttpClient.newHttpClient().send(req, HttpResponse.BodyHandlers.ofString());
System.out.println(res.body());
}
static void addFile(ByteArrayOutputStream body, String name, String path) throws Exception {
body.write(("--" + BOUNDARY + "\r\nContent-Disposition: form-data; name=\"" + name + "\"; filename=\""
+ Path.of(path).getFileName() + "\"\r\nContent-Type: application/octet-stream\r\n\r\n").getBytes(StandardCharsets.UTF_8));
body.write(Files.readAllBytes(Path.of(path)));
body.write("\r\n".getBytes(StandardCharsets.UTF_8));
}
static void addField(ByteArrayOutputStream body, String name, String value) throws Exception {
body.write(("--" + BOUNDARY + "\r\nContent-Disposition: form-data; name=\"" + name + "\"\r\n\r\n"
+ value + "\r\n").getBytes(StandardCharsets.UTF_8));
}
}#include <stdio.h>
#include <curl/curl.h>
int main(void) {
CURL *curl = curl_easy_init();
if (!curl) return 1;
struct curl_slist *headers = NULL;
headers = curl_slist_append(headers, "X-API-Key: ash_live_...");
curl_mime *mime = curl_mime_init(curl);
curl_mimepart *part;
part = curl_mime_addpart(mime);
curl_mime_name(part, "file");
curl_mime_filedata(part, "document.pdf");
curl_easy_setopt(curl, CURLOPT_MIMEPOST, mime);
curl_easy_setopt(curl, CURLOPT_URL, "https://www.ashdocs.com/api/v2/tools/pdf-linearize");
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
CURLcode rc = curl_easy_perform(curl);
printf("\n");
curl_mime_free(mime);
curl_slist_free_all(headers);
curl_easy_cleanup(curl);
return rc == CURLE_OK ? 0 : 1;
}Common use cases
- →Preparing a large PDF for embedding in a web viewer
- →Speeding up first-page display for a document library
- →Meeting a downstream system's 'Fast Web View' requirement
RELATED TOOLS
Repair PDF API
Recovers a damaged PDF through an escalating repair cascade — reports which tier actually fixed it.
PDF Info API — inspect a PDF without opening it
Page count, sizes, fonts embedded or not, forms, tagging, PDF/A claim, linearization — one call.
PDF to PDF/A API — verified archival conversion
PDF/A-2b or 3b, verified structurally (and by veraPDF when available) — never a false conformance claim.