AO-PDF Operating Limits

Every workflow processes locally in a dedicated browser worker. The common boundary is 100 MiB per file, 250 MiB aggregate, 500 PDF pages, a 120-second timeout and a 1,024 MiB estimated working-memory limit. 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.

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.