A file still readable in thirty years

State that the document follows an archiving standard: all it takes to read it again is written inside, for good.

Written at the top level of a request, under "archive"

In plain words

Written for anybody. It says what this puts on a sheet of paper, and asks nothing of you beyond that.

A contract signed today has to open again in twenty years, on a machine that does not exist yet. There is a standard for that: the file carries everything it needs, the lettering included, and points at nothing outside itself. You state it here, and the document comes out conformant. It is what public archives, courts, and more and more accounting departments ask for.

For a developer

Written for somebody who writes the calling program: the model, the units, and the settings that carry the weight.

archive states the archiving standard the document conforms to, and settles the PDF version that goes with it at the same time. Two values are in the schema: PDF/A-3 level B, which allows a file to be attached — what an electronic invoice needs — and PDF/A-4, built on PDF 2.0, which says what it is in its metadata packet and nowhere else. The standard wants the fonts written into the file: a request stating archive goes through fonts or type1_fonts.

Every key, with its default

The reference: which keys are required, which are optional, what each one defaults to and which combinations the server declines.

  • archive — string, optional, absent by default. Two values:
    • pdfa3b — PDF/A-3 level B. Imposes PDF version 1.7. It is the part that allows a file to be attached, hence the only one invoice accepts.
    • pdfa4 — PDF/A-4, ISO 19005-4. Imposes PDF version 2.0. The document carries no information dictionary, and takes a file only if that file is itself archival.
  • Fonts are written into the file. A face declared through standard_fonts is refused under this key, since nothing of the font travels with the document; fonts and type1_fonts fit.
  • output_intent states the device the colours are stated for; short of one, the document says its colours are sRGB.
  • Level A of part 3, and the level of part 4 carrying files of any kind, are planned for a future version: the first wants a structure tree a request does not yet describe, the second only means something with a file carried, and the one piece a request carries is an invoice.

A whole request that draws it

Post this as it stands and a PDF comes back. Nothing has been left out of it.

One name below stands for a font file: put the encoded file in its place, or send the file itself beside the description, as a part of the same call.

{
  "archive": "pdfa3b",
  "output_intent": { "identifier": "sRGB", "info": "sRGB IEC61966-2.1" },
  "metadata": {
    "title": "Minutes of the board meeting",
    "created": "2026-08-08T10:00:00+02:00"
  },
  "fonts": [{ "name": "body", "data": "PASTE_THE_FONT_FILE_BASE64_HERE" }],
  "items": [
    {
      "type": "text",
      "rect": { "llx": 60, "lly": 740, "urx": 535, "ury": 768 },
      "content": ["Minutes of the board meeting"],
      "font": "body",
      "font_size": 18
    }
  ]
}

The line that sends it, in three languages

The document as a whole

The numbers the reader shows A hundred letters in a single file What the document says about itself An invoice a person and a machine both read The address relative links are read against The PDF version the file declares What an image says about itself

Where to go next

Every key of a request, in one page The other thirty-two settings of a request

See the prices See the examples

Glossary

standard
A rule argued out in committee, published under a number anybody may buy and read, and identical for every firm claiming it. A claim to follow one can therefore be checked against the text. A way of working that merely spread because it worked is a habit of the trade: useful, widespread, and answerable to no text at all.
PDF/A
A PDF made to be readable in twenty years' time. Everything it needs is inside the file — the fonts, the colours, the description of what it is — so nothing it depends on can go missing later. Public bodies and archives ask for it by name.
Factur-X
An invoice that is a page for a person and a data file for a machine, in one document. The page looks like any invoice; inside, the same amounts are attached in a form accounting software reads without anybody retyping them. French law requires this exchange between companies.
the identity card of a file
The block inside a file that says what the file is: its title, who made it, when, and which rules it follows. Search engines and archives read it; a reader never sees it. Its technical name is XMP.
RGB
The three lights a screen mixes a colour from: red, green and blue. All three at full is white, all three off is black. It is how a colour is said for anything lit from behind, and the wrong way to say one for a press, which lays ink on white paper instead.
font
The drawing of every letter, digit and mark a document writes, held in a file of its own. A PDF carries the fonts it is set in inside itself, which is why it opens looking the same on a machine that has never had them. Leave them out and a reader puts another font in their place, and the layout moves.
request
One call to the service: you send what the document should say, and get the document back. Your bill counts these calls, one for each document. The number of pages inside a document is never counted.

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