PDF/A

Render a PDF/A document with pdfa.

import { render } from "takumi-pdf";

const pdf = await render(invoice, {
  pdfa: "3b",
});

Conforming output includes an sRGB output intent and XMP metadata. Fonts are always embedded and subset, with or without PDF/A.

Levels

The u levels add no output cost. Takumi always writes ToUnicode maps.

PDF/A-3 and PDF/A-4f allow arbitrary file attachments. ZUGFeRD and Factur-X electronic invoices expect "3b". See Attachments.

PDF/A-1 is not offered. It prohibits transparency.

Validation runs during rendering. When a document cannot conform, the render fails with the violated rule instead of writing a broken file.

Every level, and PDF/UA-1, passes veraPDF, the reference validator.

Tagged output

tagged defaults to true. Tagged output mirrors Chromium's print-to-PDF.

Set tagged: "ua1" to also validate against PDF/UA-1:

import { render } from "takumi-pdf";

const pdf = await render(report, {
  pdfa: "2a",
  tagged: "ua1",
  lang: "en",
  metadata: {
    title: "Annual report",
    creationDate: "2026-08-06",
  },
});

The structure tree comes from the HTML semantics:

Heading levels come from nesting, not the tag name. A document that starts with h2 gets an H1. A jump from h1 to h4 becomes H1 then H2. PDF/UA rejects a sequence that skips a level or starts below H1. HTML written for visual styling does this all the time.

Tables are missing from that list. <table> markup is not supported. Flex-row tables omit Table, TR and TH elements. Screen readers cannot navigate them by row or column. The file still passes PDF/UA-1, because the validator only checks the tags that are there.

Set tagged: false to skip the tree when file size matters more than accessibility.

PDF/UA-2

tagged: "ua2" validates against PDF/UA-2 instead. The standard is PDF 2.0 only, so it pairs with pdfa: "4", pdfa: "4f", or plain PDF.

import { render } from "takumi-pdf";

const pdf = await render(report, {
  pdfa: "4",
  tagged: "ua2",
  lang: "en",
  metadata: {
    title: "Annual report",
    creationDate: "2026-08-08",
  },
});

Links and outline entries target structure elements, not page positions. Reading order survives when a viewer follows one.

What combines with what

Invalid combinations are TypeScript type errors. PDF/UA-1 uses PDF 1.7. PDF/A-4 and PDF/UA-2 use PDF 2.0. The two generations never mix.

See Attachments.

Validators require inputs the renderer cannot supply:

• lang is the document language. A-levels and PDF/UA require it. PDF/UA-2 fails the render without it. A passage in another language needs its own lang attribute.
• metadata.title is required by PDF/UA.
• metadata.creationDate is required by the a levels. Use UTC "YYYY-MM-DD" or "YYYY-MM-DDTHH:MM:SS". A fixed date keeps output byte-identical across runs.

PDF/UA also requires a document outline. Takumi generates it from headings.