Your first PDF

curl --fail-with-body \
  -X POST __API_ORIGIN__/api/v1/pdfs/custom-template \
  -H 'Content-Type: application/json' \
  --data '{"template":{"title":"{{data.title}}","pages":[{"layout":"flow","blocks":[{"type":"heading","text":"{{labels.heading}}"},{"type":"paragraph","text":"{{data.summary}}"}]}]},"labels":{"heading":"Overview"},"data":{"title":"Project brief","summary":"Made for your app."}}' \
  --output project-brief.pdf

$baseUrl = '__API_ORIGIN__'
$requestPath = Join-Path ([IO.Path]::GetTempPath()) ([IO.Path]::GetRandomFileName())
$json = @{
  template = @{ title = '{{data.title}}'; pages = @(@{ layout = 'flow'; blocks = @(
    @{ type = 'heading'; text = '{{labels.heading}}' }
    @{ type = 'paragraph'; text = '{{data.summary}}' }
  ) }) }
  labels = @{ heading = 'Overview' }
  data = @{ title = 'Project brief'; summary = 'Made for your app.' }
} | ConvertTo-Json -Depth 10
[IO.File]::WriteAllText($requestPath, $json, [Text.UTF8Encoding]::new($false))
try {
  curl.exe --fail-with-body -X POST "$baseUrl/api/v1/pdfs/custom-template" `
    -H 'Content-Type: application/json' `
    --data-binary "@$requestPath" --output '.\project-brief.pdf'
  if ($LASTEXITCODE -ne 0) { throw 'PDF generation failed.' }
} finally { Remove-Item -LiteralPath $requestPath }

using System.Net.Http.Json;

using var client = new HttpClient { BaseAddress = new Uri("__API_ORIGIN__") };
// If required: client.DefaultRequestHeaders.Add("X-Api-Key", yourKey);
using var response = await client.PostAsJsonAsync("/api/v1/pdfs/custom-template", new
{
    template = new
    {
        title = "{{data.title}}",
        pages = new[] { new { layout = "flow", blocks = new[] {
            new { type = "heading", text = "{{labels.heading}}" },
            new { type = "paragraph", text = "{{data.summary}}" }
        } } }
    },
    labels = new { heading = "Overview" },
    data = new { title = "Project brief", summary = "Made for your app." }
});
response.EnsureSuccessStatusCode();
await File.WriteAllBytesAsync("project-brief.pdf", await response.Content.ReadAsByteArrayAsync());

import { writeFile } from 'node:fs/promises';

const response = await fetch('__API_ORIGIN__/api/v1/pdfs/custom-template', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' }, // Add X-Api-Key if required.
  body: JSON.stringify({
    template: {
      title: '{{data.title}}',
      pages: [{ layout: 'flow', blocks: [
        { type: 'heading', text: '{{labels.heading}}' },
        { type: 'paragraph', text: '{{data.summary}}' }
      ] }]
    },
    labels: { heading: 'Overview' },
    data: { title: 'Project brief', summary: 'Made for your app.' }
  })
});
if (!response.ok) throw new Error(await response.text());
await writeFile('project-brief.pdf', Buffer.from(await response.arrayBuffer()));