LexNET maximum file size, accepted formats and how to prepare your PDFs

What is the maximum file size in LexNET?

LexNET accepts 100 MB per submission and a maximum of 15 MB for the main document. The 100 MB is the sum of the filing and all its annexes.

The increase came in phases, according to the LexNET notices: on 19 July 2023 for case-initiating filings, on 4 October for the other initiating filings, on 13 October for procedural filings and on 3 November for notifications, and in every case «the restriction of a maximum of 15MB for the main document is maintained». The release notes for LexNET 5.14, from 2026, repeat it: «documents over 100MB with the main one at 15MB maximum».

Why you still see «30 MB» on many pages

30 MB was the limit from 2019 to 2023, and many news items from that time are still online. Even the Ministry's November 2025 guide, when it comes to adding annexes, talks about annexes «that do not exceed the capacity limit (30MB)», although one page earlier it sets the 100 MB for the total. None of the official sources we have checked gives a separate limit per annex: the prudent course is that none goes over 30 MB and that the whole does not go over 100.

What formats does LexNET accept?

The main document goes in PDF/A with OCR, signed; the annexes, in the formats recommended by Annex IV of Real Decreto 1065/2015 (the Spanish Royal Decree that regulates electronic communications in the justice system and LexNET).

Section 5 of that annex says that the main document «must be submitted in PDF/A format with the OCR feature (optical character recognition), that is, it must have been generated or scanned with software that produces as its final result a file in an editable text format whose content can be searched, and it must be electronically signed with the signature or signatures of the professionals involved».

For annexes, section 6 refers to the interoperability guides and, «until then», recommends the formats in the table. A .zip may only contain files in those formats.

How to tell whether a PDF has OCR

A PDF has OCR if you search for a word and the viewer finds it. It is the quickest test and it works in any viewer:

1. Open the PDF in Acrobat Reader, in the browser or in Preview.
2. Press Ctrl + F on Windows or Cmd + F on a Mac.
3. Search for a word you can see on a page in the middle, not on the first one.
4. If it doesn't find it, that page is an image with no text: it has to be scanned again with OCR turned on.

PDF/A is something else: the version of PDF designed for archiving, which according to Microsoft «helps ensure a document will look the same when it is opened later on a different computer». A filing exported from Word with the PDF/A box ticked meets both conditions, because the text comes out as text. Except with the option «Bitmap text when fonts may not be embedded»: text whose font cannot be embedded is saved as an image, and the search does not find it.

How do you export to PDF/A from Word?

In Word for Windows, PDF/A is turned on with a box when you save as PDF. It is the method the Ministry explains in its manual «Convertir documentos Word a PDF/A» (converting Word documents to PDF/A).

1. With the filing finished, go to File, choose Save As (or Save a Copy) and click More options.
2. In the file type, choose PDF.
3. Click Options and tick ISO 19005-1 compliant (PDF/A).
4. Under Publish what, leave Document. With «Document showing markup», the PDF would come out with the tracked changes.
5. Click OK and then Save.

The Ministry's manual also gives the route File, Export, Change File Type, Save As, which leads to the same box. Before exporting, accept or reject any pending changes and remove the comments: we explain it in Track Changes in Word.

On a Mac

Microsoft's help for Word for Mac does not include the PDF/A option, and the Preview user guide doesn't mention it when exporting either. On a Mac you need a program that exports to PDF/A, or to do the final export on a computer with Word for Windows.

And if on a Mac you choose Best for electronic distribution and accessibility (uses Microsoft online service), Word «sends the document to a secure Microsoft service over the Internet for conversion». Microsoft says it does not keep the content, but the filing leaves your computer.

How do you reduce the size of a PDF for LexNET?

Most of the size is saved when scanning: 200 dpi, in black and with OCR, as Annex IV recommends.

When scanning, on Windows and Mac

Section 8 of Annex IV recommends setting up the scanner like this:

1. A resolution of 200 x 200 dpi «or, failing that, the minimum the device allows».
2. Output type PDF/A.
3. Output as a single document.
4. OCR turned on.
5. Black output colour. Colour «only» when the content requires it.

With that setup, according to the Ministry's good practice guide, «LexNET allows a text document of more than 300 pages to be sent electronically».

In Word, before exporting

If the filing has photos or screenshots pasted in, compress them in Word before turning it into a PDF. On Windows: select the image and go to Picture Format, Adjust group, Compress Pictures, and choose the resolution. On a Mac, File, Compress Pictures does it for all the images in the document at once.

On a Mac, with Preview

1. Open the PDF and choose File, Export.
2. In the Quartz Filter menu, select Reduce File Size. If you prefer more control, tick only Optimise images for screen or Save images as JPEG.
3. Save it under a different name to keep the original.

Apple warns that «the PDF may be of lower quality than the original file». Check that the result is easy to read and that Cmd + F still finds the text.

On Windows

Windows doesn't come with a feature like Preview's to compress a finished PDF. The practical route is to scan again with the Annex IV settings or to compress the images in Word before exporting; if the firm has a PDF editor, use it on the computer itself.

And an honest limit: if the document has to become illegible to fit, it is no longer worth compressing further. For when the submission doesn't fit, LexNET has the exceso de cabida (oversize) procedure, which we explain further down.

How do you split or merge annexes in PDF?

LexNET asks for one file per document: a scan containing several documents is split, and a document scanned in parts is merged.

Annex IV requires annexes to be sent «individually in as many digital files as there are documents making up the submission». And the LexNET FAQ explains why the system doesn't split them for you: the digital signature guarantees the integrity of each document and the system cannot modify them.

On a Mac, with Preview

• Split: open the PDF, choose View, Thumbnails, select the pages of one document and drag them to the desktop. Preview creates a new PDF with them.
• Merge: open both PDFs with the thumbnails showing and drag those of one into the sidebar of the other, in the order you want. To add a whole PDF, drag its icon from the Finder to that sidebar.
• Remove pages that are blank or repeated: select them in the thumbnails and press Delete, or choose Edit, Delete.

Preview saves changes automatically: Apple advises doing File, Duplicate first to keep the original.

On Windows, with the PDF printer

1. Open the PDF in your viewer (Acrobat Reader or the browser) and choose Print.
2. As the printer, choose Microsoft Print to PDF, which comes with Windows 10 and Windows 11.
3. In the pages, enter only those of that document (for example, 4 to 9) and print.
4. Give it its name (next section) and repeat with the next document.

The result is a new, printed PDF: Microsoft doesn't say that it keeps PDF/A or the text layer, so check it with Ctrl + F. To merge, Windows has no feature of its own: combine the Word documents in Word before exporting, and scan the paper in one go, as «a single document», which is what Annex IV recommends.

How do you name the files and make the index of documents?

Each file starts with its sequence number, followed by the type of document and a brief description.

That is what Annex IV requires: the name «must be preceded by the cardinal number corresponding to the place or order they will occupy when attached» and include «their type and a brief description, a merely generic or numerical reference not being sufficient». That is why «scan0003.pdf» or «annex.pdf» will not do.

Since LexNET 5.7, file names accept every character that Windows accepts except \ / : * ? " < > |. Watch out for dates written with slashes.

The index of documents

The index is required by article 9.3 of Real Decreto 1065/2015: a standard form with «the detail or index covering the number, order and brief description of the content of each of the documents». In LexNET, according to the Ministry's guide, each annex is uploaded, catalogued and put in order by dragging it or with the Ordenar (sort) option. The receipt then records «the description of each of the documents transmitted» (article 17.3).

The practical thing is to make the list once, before scanning: number, type and description of each document, in a Word table. From that list come the name of each file, the order in which you upload them and the way you cite them in the filing («documento n.º 3», document no. 3), so all three match.

How do you file a document in LexNET, step by step?

A filing is submitted on the LexNET website with your certificate: form, main document, annexes and Firmar y enviar (sign and send). These are the steps according to the Ministry's guide for procedural filings (November 2025):

1. Go to lexnet.justicia.es, the address set by Annex IV, with your electronic certificate (if it is the one issued by the Spanish bar, how to install it is in the ACA certificate on Windows and Mac).
2. In the Escritos (filings) menu, choose De Trámite (procedural). Initiating filings and other types have their own guide.
3. Fill in the form: sender, destination court and proceedings, parties and, if you wish, the details of the filing.
4. Attach the main document first: it is mandatory and must be a PDF.
5. Add the annexes (you can drag several at once), put them in order and catalogue them.
6. Click Firmar y enviar (sign and send). The system asks for your card's PIN.
7. Download the receipt from the Acuses de recibo (receipts) folder.

The guides for each type of filing are in the LexNET user guides (in Spanish).

If it doesn't fit: the exceso de cabida

If the main document is over 15 MB or the submission over 100 MB, when you click Firmar y enviar LexNET shows an error and offers to download the exceso de cabida (oversize) receipt, or to send the filing with the main document, that receipt as the only annex and the flag «Documentación pendiente de completar» (documentation pending completion). You can also go back and remove annexes. How you provide afterwards what didn't fit is governed by article 18 of Real Decreto 1065/2015, and the Ministry's guides refer you to the Acceda service for it.

And before the PDF, the filing

In short

LexNET accepts 100 MB per submission and 15 MB for the main document since October 2023; the 30 MB still going around is from 2019. The main document goes in PDF/A with OCR, signed, and each annex in its own file, with sequence number, type and description in the name. Scan at 200 dpi, in black and with OCR; split, merge and compress on your own computer before signing, and don't upload client documents to compression websites.

Sources: BOE, Real Decreto 1065/2015, on electronic communications in the Administration of Justice and the LexNET system (in Spanish; articles 9, 17 and 18 and Annexes II and IV; consolidated text, unchanged since publication); Ministry of Justice, LexNET notices (in Spanish) of 19 July and 4 October 2023, LexNET increases the capacity of message types to 100MB (in Spanish) and Justice extends LexNET's sending capacity to 100 MB (in Spanish, 24 July 2023); Ministry guides Submitting procedural filings (in Spanish, November 2025), What's new in LexNET 5.14 (in Spanish, 2026), What's new in LexNET 5.7 (in Spanish, 2024), LexNET good practices (in Spanish, 2023) and Converting Word documents to PDF/A (in Spanish); LexNET frequently asked questions (in Spanish) and operating system requirements (in Spanish, January 2026); Abogacía Española, the Ministry of Justice doubles LexNET's sending capacity to 30 MB (in Spanish, 2019); Microsoft, Save or convert to PDF, Create accessible PDFs, Reduce the file size of your images and Microsoft Print to PDF; Apple, Preview User Guide: Reduce the file size of a PDF, Combine PDFs and Add, delete or move pages. Checked on 23 October 2026.

Frequently asked questions

What formats does LexNET accept?

The main document goes in PDF/A with OCR, signed. For annexes, Annex IV of Real Decreto 1065/2015 recommends .pdf, .rtf, .jpeg, .jpg, .tiff, .odt and .zip, and a .zip may only contain files in those same formats.

What is the maximum size of a document in LexNET?

15 MB for the main document and 100 MB for the whole submission, annexes included. These are the limits the Ministry published in 2023 and repeats in its 2025 and 2026 guides; the 30 MB that still appears on many pages is the 2019 figure.

Can I send all the annexes in a single PDF?

No. Annex IV of Real Decreto 1065/2015 says that «it is not possible to send a single PDF containing all the documents»: each document goes in its own file, with its sequence number, its type and a brief description in the name.

How do I file a document in LexNET?

Go to lexnet.justicia.es with your certificate, choose the type in the Escritos (filings) menu, fill in the form, attach the main document in PDF and the annexes, and click Firmar y enviar (sign and send). The Ministry publishes a guide for each type of filing in the LexNET user guides (in Spanish).

How do I update LexNET?

LexNET is not installed: it is a web service, and the Ministry rolls out each version (5.15 was announced on 30 September 2026) and announces downtime on the LexNET notices page. On your computer, what you need to keep up to date is the operating system and the browser.

Who has access to LexNET?

The groups listed in Annex II of Real Decreto 1065/2015: among others, lawyers, procuradores (court representatives), graduados sociales (labour law advisers), the Public Prosecutor's Office, the State Attorney's Office and insolvency administrators. According to the LexNET FAQ, a lawyer registered with a bar association is enrolled automatically, needs an accepted certificate and it can take up to 48 working hours; in the autonomous communities that manage their own justice services, it also refers you to their support centre.

What are the technical requirements for LexNET?

An accepted electronic certificate and an up-to-date computer. Since January 2026, the Ministry recommends at least Windows 11 or macOS Tahoe 26.0 and the latest version of the browser. Without an installed certificate, lexnet.justicia.es shows that it has not detected any valid certificate.