Generating and Compiling

picture_as_pdf Compile from the preview

The quickest way to see your paper is the PDF preview on the right of the editor. Press Compile in its header and TeXpress pours the tabs into your journal's template and builds the PDF, right there beside the text you are editing. You never leave the tab you were on.

A bar sweeps across the preview while it works. A compile takes anything from a few seconds to about a minute, depending on the paper.
When it is done, the download and open-in-a-new-tab icons appear in the preview's header, and Download PDF appears in the top bar.
If the compile fails, the preview names the first error and links to the LaTeX editor, which is where the full explanation, Fix with AI and Report issue live. All three are described below.
Preview hidden? Press Preview at the right end of the tab row, or click the thin strip on the right edge of the window.

bolt Generate TeX / ZIP

The button in the top bar, and again at the end of the last tab. Use it when you want the LaTeX itself or the files to take away. Pressing it does three things in order:

1 Pours your content into your chosen journal's own LaTeX template: its class file, its author block style, its citation style, its numbering.
2 Opens the LaTeX and PDF page: your generated source on the left, the PDF on the right.
3 Compiles it once, automatically. A short console tells you which stage it is on.

Greyed out? You have not chosen a journal. There is no such thing as journal-neutral LaTeX to compile, so Generate and Compile both wait for you, and a banner at the top of the tab says so. Open Project Settings (or click "Choose a journal" in that banner), pick a journal, and they light up.

Nothing is spent. Generating and compiling use no AI and no quota. Press them as often as you like, including once early just to see what your paper looks like.

The LaTeX and PDF page

Two panes. On the left, the actual main.tex that was generated, with syntax highlighting. On the right, the compiled PDF. Above them: a status badge, Recompile, and the download buttons.

You can edit that LaTeX. If you know LaTeX and want one thing exactly so, change it and press Recompile.
Editing it is a one-way door. Once you save an edit, that text is what compiles, and the editor tabs no longer feed the PDF. A badge appears saying "Manual LaTeX edits active", and a banner on the tabs reminds you that what you see there is no longer what compiles.
Getting back is easy and never destructive. From that banner you can discard the manual edits and let the tabs take over again, keep the LaTeX as final and stop being reminded, or on a paid plan re-import the edited LaTeX back into the tabs with AI. Whichever you choose, a snapshot of your edits is saved first, and you can restore it from Activity.
Pressing Generate again from the tabs while manual edits are active asks you to confirm, and explains that the snapshot is being taken. It never silently overwrites your work.

Most people never touch this pane, and that is the intended experience. It exists so that knowing LaTeX is an advantage in TeXpress rather than an escape hatch you are forced into.

When a compile fails

LaTeX is strict, and a real manuscript hits an error sooner or later. It is not a lost afternoon. A failure shows you a plain-English window naming what went wrong, and behind it the technical log with the exact line. You can reopen that window any time from View compile error.

Your work is never lost in a failed compile. Nothing is deleted, nothing is rewritten. You still have the previous PDF if there was one, and every tab is exactly as you left it.

The ones you will actually meet

A special character the font can't print expand_more

By far the most common one, and it almost always comes in with pasted text. A curly quote, an en dash, a real minus sign, or a maths symbol such as ∈ or β sitting in an ordinary sentence. We tell you which field it is in. Replace it with the plain equivalent, or wrap the maths symbol in $...$ so LaTeX treats it as maths.

Math symbol used outside math mode expand_more

The same family of problem: a ^, an underscore or a Greek-letter command written in running text. Wrap the expression in $...$ , or use the Math toolbar button, which does it for you.

Your bibliography is empty expand_more

Nothing in your text cites a reference, or a citation points at a key that no entry has. A reference is printed only when a Cite marker in your text reaches it, and the References tab marks every entry Cited or Not cited so you can see which. Inserting citations with the Cite button rather than typing them keeps the keys in step.

Unrecognized command expand_more

LaTeX met a backslash command it does not know. Nearly always a typo in an equation, or a macro that came in from an imported .tex file and was defined in a preamble we did not receive. The log names the line. Replace it with a standard command.

Unmatched brace, or mismatched environment expand_more

A { without its }, or a block opened as one thing and closed as another. Look at whichever equation or pasted LaTeX you touched last. If you pasted through LaTeX view, the error list there points at the problem before anything is applied.

Missing file expand_more

Something the document asks for is not there, usually a figure image on a project imported from .tex. Open the Figures tab and check every card actually has an image.

A font or a service problem, which is ours and not yours expand_more

Two messages say so outright. "We're missing a font this journal needs" means your document needs a maths font we do not have yet for that journal's style: tell us and we will add it, usually quickly, and in the meantime a plainer symbol will get you past it. "Compile service temporarily unavailable" means the compiler did not answer at all: wait a moment and press Recompile. Neither is a mistake in your manuscript.

auto_awesome Fix with AI

Next to the compile log on a failed compile. It reads the error and the surrounding LaTeX, rewrites the part it thinks is wrong, and recompiles.

It is worth a try, not a guarantee. It is good at the mechanical failures: a stray brace, a bad character, a command that needs escaping. It cannot know that you meant a different symbol.
It costs one extraction from your monthly allowance, and it is available on paid plans. The button tells you what it will spend and which key it will spend before you press it. If your own API key is switched on, it uses that instead.
It edits the LaTeX, which means it puts the project into manual-edits mode. That is reversible exactly as described above.
On a shared project it always spends the owner's plan, never the collaborator's.

bug_report Report issue

Beside the compile log, and in the error window itself. Use it when you have read the message and it is not something you can act on: a font we do not have, a journal template behaving oddly, or an error that makes no sense against what is in your tabs.

You do not have to describe the setup. The report carries your project name, the journal you picked and the exact errors that were on your screen, so we can reproduce it without a back-and-forth. The box is there for anything else worth knowing.
Reporting the same project twice while you retry tells you the first report is still open rather than filing a second one.
You get told when it is fixed. A notification appears under the bell in the header, with a link straight back to the project so you can compile again. We will email you as well if it is the kind of thing worth interrupting you for.
It works on a shared project too, and the reply goes to whoever reported it rather than to the owner.

Downloads

All four live on the LaTeX and PDF page, which is where Generate TeX / ZIP takes you. The PDF and ZIP need a successful compile; the other two do not. The PDF can also be downloaded from the editor's top bar and from the preview.

picture_as_pdf

PDF

The compiled document, laid out by the journal's own template. This is what a reviewer or an editor sees, and for most submission systems it is the file you upload.

folder_zip

ZIP

The complete LaTeX source package: main.tex, references.bib, a figures/ folder with your images, and the journal's class and style files. This is what publishers mean when they ask for "the LaTeX source", and it is what you would hand to a co-author who works in Overleaf.

download

main.tex on its own

The small download icon in the editor pane header. Just the source file, for when you want to read or diff it.

description

Word (.docx)

Your manuscript as a real Word document: headings, paragraphs, tables, figures, editable equations and your reference list. It is built from your content, not from the PDF, so it works even while a compile is failing.

It is not a copy of the PDF. A journal's layout comes from its LaTeX class file, which Word cannot reproduce, so spacing, column breaks and the exact reference style will differ. Use it for co-author review, for track changes, or for a publisher that asks for Word. When the exact format matters, send the PDF or the ZIP. A short reminder of this appears every time you download it.

fact_check After the journal sends a proof

Once a paper is accepted, the journal lays it out in its final form and sends back a proof with its own small edits and questions for you: as a ZIP of LaTeX files, as a PDF with comments on it, or as a Word file with tracked changes. Journal proof, in the Workflow list at the foot of the editor's left-hand rail, imports any of the three and shows one card per edit or question, so you decide and reply without opening the files. The whole flow, from the locked link to what you send back, is on its own page: Journal Proofs.

Before that stage, the same Workflow list holds the Cover letter for your submission and the Reviewer response for each revision. Both are explained in Submitting and Revising.

Switching journals

Open Project Settings, choose a different journal, then press Generate again. That is the whole procedure. Your content does not change; only the template it is poured into does. Two things to expect: if the new journal allows fewer heading levels than you have used you are warned before anything happens, and journal-specific fields such as research highlights are kept but simply not printed by a journal that has no place for them.

One honest note about layout

LaTeX decides page breaks and where floats land, and it will move a figure or a table to the next page to avoid leaving a gap. Every journal-formatted paper you have ever read was laid out this way. Placement settings are hints that LaTeX takes seriously, not coordinates. If a float is a page away from its mention, that is the layout engine doing its job, and reviewers are used to it.