PDF Watermark

Lays a visible watermark over the pages of a PDF: text, a logo or both, tiled, centred or in a corner.#

Marks every page of a PDF, or the zero-based 'pages' named, with 'watermark': a line of text, a logo (its transparency kept) or both, tiled on a diagonal lattice, centred along the page's diagonal or in a corner, at an opacity, size and angle, legible on light and dark content alike. The mark is vector artwork drawn once and referenced by every copy, laid above the page content: it stays sharp at any zoom, adds a few kilobytes to the file, and leaves the page's own text selectable and searchable (the mark adds no text). It reads upright on turned pages and inside cropped ones. Every copy is tagged as a watermark artifact, so marking a document again replaces the mark ('replace_existing', default true) and POST /lmkit/v1/pdf-remove-watermark takes it off. The document is stored on the server and returned as a 'file_id'. No AI model is involved. A signed document is refused with 422 'signed_document' unless 'allow_signature_invalidation' consents to the rewrite that invalidates its signatures; a document declaring PDF/A-1, which forbids transparency, with 422 'pdfa_forbids_transparency' (convert it to PDF/A-2 with POST /lmkit/v1/pdf-to-pdfa first); watermark text holding a character no font on the server draws with 422 'unsupported_characters', naming it. Other unreadable inputs answer 422 with 'password_required', 'invalid_format', 'unsupported_security' or 'page_error'. If processing exceeds the configured timeout, returns 202 Accepted with a job_id to poll at GET /lmkit/v1/jobs/.

Request body

application/json · PdfWatermarkRequest

Responses

curl -X POST "$LMKIT_ONE_URL/lmkit/v1/pdf-watermark" \
  -H "Authorization: Bearer $LMKIT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "watermark": {
    "text": "string",
    "logo": "string",
    "logo_file_id": "string",
    "font": "string"
  },
  "replace_existing": true,
  "input": "",
  "input_format": "Base64EncodedFile",
  "pages": [
    "string"
  ],
  "allow_signature_invalidation": false
}'

Removes the watermarks laid over the pages of a PDF.#

Takes off every watermark POST /lmkit/v1/pdf-watermark laid (and any other content tagged as a watermark artifact) from every page, or from the zero-based 'pages' named. The rest of each page is untouched. The document is stored on the server and returned as a 'file_id' with the number of copies removed. A signed document is refused with 422 'signed_document' unless 'allow_signature_invalidation' consents; other unreadable inputs answer 422 as for POST /lmkit/v1/pdf-watermark.

Request body

application/json · PdfRemoveWatermarkRequest

Responses

curl -X POST "$LMKIT_ONE_URL/lmkit/v1/pdf-remove-watermark" \
  -H "Authorization: Bearer $LMKIT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "input": "",
  "input_format": "Base64EncodedFile",
  "pages": [
    "string"
  ],
  "allow_signature_invalidation": false,
  "password": "string"
}'

What the watermark engine on this server accepts.#

The 'watermark.layout' values, the longest 'watermark.text', and whether fonts are installed on the server, derived from the engine. Cacheable for five minutes.

Responses

curl -X GET "$LMKIT_ONE_URL/lmkit/v1/pdf-watermark/capabilities" \
  -H "Authorization: Bearer $LMKIT_API_KEY"