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PDF Compressor

Compress PDF documents to reduce file size. Optimizes embedded images, fonts, and document structure.

Try PDF compression in the browser →

Compress.FAST uses this same API — what you see in the browser is what you get in code.

Quick reference

Job typedocument.pdf-compress
Categorydocuments
EndpointPOST /compress/pdf
Input formats.pdf
Output formatsame as input
Costing1 credit per 5 MB
Max file size1 GB
Optionsnone

Example

cURL 
# 1) submit
JOB_ID=$(curl -sS -X POST "https://api.tools.fast/compress" \
  -H "X-Fast-Api-Key: $API_KEY" \
  -F "file=@document.pdf" | jq -r '.id')

# 2) poll until complete
while true; do
  STATUS=$(curl -sS "https://api.tools.fast/compress/job/${JOB_ID}" \
    -H "X-Fast-Api-Key: $API_KEY" | jq -r '.status')
  [ "${STATUS}" = "Succeeded" ] && break
  [ "${STATUS}" = "Failed" ] || [ "${STATUS}" = "Canceled" ] && exit 1
  sleep 1
done

# 3) download
curl -sS "https://api.tools.fast/compress/job/${JOB_ID}/download" \
  -H "X-Fast-Api-Key: $API_KEY" \
  -o "document-compressed.pdf"
C# 
using var http = new HttpClient();
http.DefaultRequestHeaders.Add("X-Fast-Api-Key", "fast_prod_your_key_here");

using var form = new MultipartFormDataContent();
form.Add(new ByteArrayContent(File.ReadAllBytes("document.pdf")), "file", "document.pdf");

var submit = await http.PostAsync("https://api.tools.fast/compress", form);
var job = await submit.Content.ReadFromJsonAsync<JsonElement>();
var jobId = job.GetProperty("id").GetString();

string status;
do
{
    await Task.Delay(1000);
    var poll = await http.GetFromJsonAsync<JsonElement>(
        $"https://api.tools.fast/compress/job/{jobId}");
    status = poll.GetProperty("status").GetString()!;
} while (status is "Queued" or "Running");

var output = await http.GetByteArrayAsync(
    $"https://api.tools.fast/compress/job/{jobId}/download");
File.WriteAllBytes("document-compressed.pdf", output);
PowerShell 
$headers = @{ "X-Fast-Api-Key" = "fast_prod_your_key_here" }

# 1) submit
$job = Invoke-RestMethod -Method Post "https://api.tools.fast/compress" `
  -Headers $headers `
  -Form @{ file = Get-Item "document.pdf" }

# 2) poll until complete
do {
  $status = (Invoke-RestMethod "https://api.tools.fast/compress/job/$($job.id)" `
    -Headers $headers).status
  if ($status -in "Failed", "Canceled") { throw "Job $($job.id) $status" }
  Start-Sleep -Seconds 1
} while ($status -ne "Succeeded")

# 3) download
Invoke-RestMethod "https://api.tools.fast/compress/job/$($job.id)/download" `
  -Headers $headers -OutFile "document-compressed.pdf"

Options

The PDF compressor has no user-controllable options. Compression settings are automatically optimized -- embedded images are recompressed, fonts are subsetted, and the document is linearized for web viewing.

Notes

  • Output format: .pdf -- same as input.
  • Embedded images are recompressed to reduce file size.
  • Font subsetting and deduplication are applied where possible.
  • Password-protected PDFs (those requiring a password to open) are not supported and will be rejected at submission. Remove the password before compressing.
  • The document structure, bookmarks, and hyperlinks are preserved.
  • For converting PDFs to other formats, use Convert.FAST.
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