AO-PDF Operating Limits

Every workflow processes locally. Transformations use the AO-PDF operation worker; assurance parsing uses PDF.js's local worker while local rendering, hashing and packaging remain in the browser. The common boundary is 100 MiB per file, 250 MiB aggregate, up to 500 PDF pages, a 120-second timeout and a 1,024 MiB estimated working-memory limit. Permanent redaction is additionally capped at 50 pages. Encrypted PDFs are unsupported.

Tool-specific operating limits
Tool	Inputs	Page limit	Material limitations
Merge PDFs	2–20	500	Encrypted PDFs are not supported. Source metadata is not copied into the new merged document.
Split PDF	1–1	500	Split-every-page is limited to 200 output documents. Each output is a new document and does not retain full source metadata.
Optimize PDF	1–1	500	Optimization rebuilds object streams but does not recompress images. Some documents will remain the same size or become larger.
Rotate Pages	1–1	500	Every page is rotated by the selected angle.
Delete Pages	1–1	500	At least one page must remain in the output.
Add Watermark	1–1	500	Watermark text is limited to 120 printable Latin characters. The watermark is applied to every page.
Add Page Numbers	1–1	500	Only the displayed top and bottom positions are supported.
Flatten Form Fields	1–1	500	Only tested AcroForm text, checkbox, radio, dropdown, and option-list fields are supported. XFA, signature, and unsupported button widgets are rejected.
Images to PDF	1–20	20	Only JPG and PNG images are supported. Each image becomes one PDF page and no OCR is performed.
Inspect PDF	1–1	500	Findings are parser-observable facts and warnings, not threat verdicts. Embedded content is identified only where the browser parser exposes it.
Compare Documents	2–2	500	Text extraction does not perform OCR on scanned pages. Rendered comparison is fixed at 96 DPI and does not establish semantic or legal equivalence.
Evidence Manifest	1–20	500	SHA-256 records byte equality only. A manifest does not prove authenticity, ownership, chronology, admissibility, or chain of custody.
Permanent Redaction	1–1	50	Supported inputs are reconstructed as image-only pages at 144 DPI before redaction rectangles are burned into the pixels. Annotations, attachments, forms, JavaScript, incremental revisions, encryption, and malformed PDFs are rejected. The output loses selectable text, accessibility structure, links, forms, signatures, attachments, and metadata.

Estimated memory is not measured memory

AO-PDF conservatively estimates working bytes from input size, decoded image pixels, page-object overhead, simultaneous outputs, serialization duplication and operation multipliers. Browsers do not expose a reliable cross-browser measurement of PDF-library memory. Passing admission does not guarantee that a device can complete an operation.