# Flatten PDF > A free online tool that turns the form fields and annotations of a PDF (stamps, highlights, shapes) into fixed page content, keeps links clickable and cannot be undone. Flatten PDF files here to turn form fields and annotations into fixed page content. Flattening cannot be undone, so keep your original file. It is not a security feature and it is not redaction; it does not delete content. Links stay clickable, and any annotation without a picture of its own is left as it is and counted in the result panel. ## Key facts - Input: one PDF up to 10 MB without an account (50 MB signed in), up to 100 pages (500 signed in), with up to 20,000 form fields and annotations; password-protected PDFs are refused. - Settings: flatten form fields and annotations (the default), form fields only, or annotations only; the result is flattened.pdf with the same pages. Links always stay clickable. - Flattening cannot be undone and is not redaction or a security feature; an annotation without a picture of its own, and one that keeps its direction on a turned page, is left as it is and counted in the result panel; a digital signature can become invalid. - In our test a generated 2 page form of 10 KB with 9 form fields and 5 annotations became an 8.7 KB PDF with 9 fields and 3 annotations flattened, 1 link kept and 1 comment note left because it had no picture; a PDF with nothing to flatten came back unchanged and free; results vary with the file. - API: POST the PDF to https://api.aiipworld.com/v1/uploads, then POST https://api.aiipworld.com/v1/pdf-jobs with op pdf_flatten, what (all, forms or annotations) and the upload id, and poll GET /v1/jobs/:id. - Free without an account: 20 PDF jobs per day per visitor, no watermark. Signed in, each job costs 1 credit, plus 1 credit for each started 20 MB of result beyond the first 20 MB, and a PDF with nothing to flatten costs nothing (100 free credits every month). - Files are deleted automatically: 10 minutes after conversion without an account, 1 day with a free account. ## How it works 1. Upload the PDF you want to flatten. Your browser checks the file type before upload, and our server checks it again. 2. Choose what to flatten: form fields and annotations, form fields only, or annotations only. 3. Leave "Repair a slightly damaged PDF automatically" on, unless you want damaged files refused. 4. Start the job and wait for the result panel. 5. Download flattened.pdf and keep your original file. ## How to flatten a PDF Flatten PDF files in four steps: upload, choose what to flatten, run the job, and download the result. The tool returns a new PDF named flattened.pdf with the same pages in the same order. Your original file is not changed, so you can always go back to it. You can flatten PDF online with this tool without installing anything. Anonymous use needs a human check through Cloudflare Turnstile. Signed-in users skip it and use credits. - Keep the original file before you start. - Check the result panel after the job ends. ## What Flatten PDF does to form fields and annotations As a pdf flattener, this tool draws the picture of each form field and annotation into the page. The field or annotation object is then removed, so the content is fixed. Text stays as text, and in our test the values typed into form fields could still be found as text in the result. A pdf flatten job changes the form and the annotations; it does not change the look of the page. Common reasons people flatten a file are to stop a filled form from being edited by mistake, to make every viewer show the same values, and to print or send a filled form as a fixed document. ## Forms, annotations or both You choose what to flatten. "Form fields and annotations (everything)" is the default. "Form fields only" turns text boxes, check boxes, radio buttons and drop-down lists into fixed content and keeps annotations. "Annotations only (stamps, highlights, shapes)" flattens those and keeps form fields fillable. When all form fields are flattened, the whole form, including its field list and scripts, is removed from the file. Hidden form fields and hidden annotations are removed too, and the result panel counts them. ## Links stay clickable Links always stay clickable in every mode. The result panel says how many links were kept. You do not need to add them again after flattening. Flattening does not remove links, so a link in your form still works in the flattened file. ## Flattening cannot be undone Once a file is flattened, the form fields and editable annotations are gone. The result has no fillable fields and no editable annotations. Keep your original file if you may need to change anything later. Flattening is not a security feature and it is not redaction. It does not delete content, and it does not stop a determined person from changing the file. ## Annotations that cannot be flattened Some annotations have no picture of their own. Some programs save only a position and a note text, and these cannot be flattened. They are left as they are, and the result panel says how many. In our test, a comment note without a picture stayed in the file. Annotations marked to keep their size and direction when the page is turned are also left as they are. Comment note icons are often like this. A pop-up window of a comment goes away together with its comment. ## When Flatten PDF has nothing to flatten A PDF with no form fields and no annotations succeeds. The file is returned unchanged, with the same bytes, and the result panel says "This PDF has no form fields or annotations to flatten". No credits are used. Running the tool on a file that has nothing left to flatten gives the same result. In our test, a 6 page text PDF with no fields (51 KB) came back unchanged with no credits, and so did the flattened form when it was run a second time. ## Digital signatures, XFA forms and protected PDFs Flattening changes the file, so a digital signature can become invalid. Dynamic XFA forms are a limit too: only the standard form fields can be flattened. Password-protected PDFs are refused by this tool. If you know the password, use Unlock PDF first, then flatten the file. ## Limits: size, pages and credits Form fields and annotations together can be up to 20,000 in one PDF. More than that makes the job fail. A PDF can be up to 10 MB without an account and 50 MB signed in, with up to 100 pages without an account and 500 signed in. A job uses 1 credit, plus 1 credit for each started 20 MB of the result beyond the first 20 MB. Failed and timed-out jobs are refunded in full. Free web tool use is limited to 20 PDF jobs per day per visitor. Results are kept for 10 minutes in the free web tool. ## Flatten a PDF from code Upload the file first. Send a POST to https://api.aiipworld.com/v1/uploads with the raw bytes and Content-Type application/pdf. The answer has an upload_id. Then send a POST to https://api.aiipworld.com/v1/pdf-jobs with JSON {op, params, files: [upload_id]}, using op pdf_flatten. Poll GET /v1/jobs/:id until the job succeeds, fails or times out. The params are what (all by default, forms or annotations) and allow_repair. The page shows a ready cURL, Node and Python example built from your settings. Errors include 422 not_a_pdf, 404 upload_not_found, and job errors such as encrypted_pdf, corrupt_pdf and too_many_annotations. ## Questions ### Can I flatten a PDF for free? Yes, you can flatten a PDF for free in the web tool, with no signup. Anonymous use needs a human check, and it is limited per day per visitor. ### What does flatten PDF mean? Flatten PDF means turning the form fields and annotations in a PDF into fixed page content. The fields and annotations stop being editable, but the page looks the same. ### How do I flatten a PDF? Upload the file, choose what to flatten, run the job, and download flattened.pdf. Keep your original file, because the result cannot be edited back. ### Can I undo flattening? No, flattening cannot be undone. Keep your original file if you may need the fillable fields or editable annotations later. ### Do links still work after flattening? Yes, links always stay and remain clickable in every mode. The result panel says how many links were kept. ### Why were some annotations left as they are? Some annotations have no picture of their own, so they cannot be flattened. Annotations marked to keep their size and direction on turned pages are also left as they are. The result panel counts them. ### Does the text stay selectable? Text stays as text in the flattened file. In our test, values typed into form fields could still be found as text in the result. ### What happens if my PDF has nothing to flatten? The file is returned unchanged, and the result panel says there is nothing to flatten. No credits are used. ### Can I flatten a password-protected PDF? No, this tool refuses password-protected PDFs. If you know the password, use Unlock PDF first. ### Can I flatten a PDF in my own code? Yes, you can use the API with op pdf_flatten. Upload the file, create a job, and poll until it finishes. ## Related - [Unlock PDF: Remove the Password from Your PDF](https://aiipworld.com/tools/unlock-pdf/index.md) - [Password Protect PDF](https://aiipworld.com/tools/protect-pdf/index.md) - [Merge PDF Files Online for Free](https://aiipworld.com/tools/merge-pdf/index.md) - [Split PDF Online, Free](https://aiipworld.com/tools/split-pdf/index.md) - [Resize PDF](https://aiipworld.com/tools/resize-pdf/index.md) - [Rotate PDF Online for Free](https://aiipworld.com/tools/rotate-pdf/index.md) Page: https://aiipworld.com/tools/flatten-pdf/