> ## Documentation Index
> Fetch the complete documentation index at: https://resources.latex-cloud-studio.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Choosing a LaTeX Compiler

> Understand different LaTeX compilers and engines. Learn about pdfLaTeX, XeLaTeX, and LuaLaTeX to choose the right one for your documents.

export const RenderedOutput = ({title = "Rendered output", ctaHref, ctaLabel = "Open LaTeX Cloud Studio", children}) => {
  const [isExpanded, setIsExpanded] = useState(false);
  const trackEditorCta = () => {
    const target = new URL(ctaHref, window.location.href);
    globalThis.posthog?.capture?.("docs_app_cta_clicked", {
      source_page: window.location.pathname,
      source_section: "rendered_output",
      cta_variant: "first_compiled_example",
      target_url: target.toString(),
      target_utm_source: target.searchParams.get("utm_source"),
      target_utm_medium: target.searchParams.get("utm_medium"),
      target_utm_campaign: target.searchParams.get("utm_campaign"),
      target_utm_content: target.searchParams.get("utm_content")
    }, {
      transport: "sendBeacon",
      send_instantly: true
    });
  };
  return <details className="rendered-output" onToggle={event => setIsExpanded(event.currentTarget.open)}>
      <summary className="rendered-output__summary">
        <span className="rendered-output__title">{title}</span>
        <span className="rendered-output__hint" aria-hidden="true">View compiled result</span>
      </summary>
      {isExpanded && <div className="rendered-output__content">
          {children}
          {ctaHref && <aside className="rendered-output__cta" aria-label="Continue in the LaTeX editor">
              <span>
                <strong>Ready to use this syntax?</strong>
                Continue in the browser editor when you want to adapt the example in a real project.
              </span>
              <a href={ctaHref} onClick={trackEditorCta}>{ctaLabel}<span aria-hidden="true"> →</span></a>
            </aside>}
        </div>}
    </details>;
};

export const LatexSource = ({filename, source}) => {
  const [copyStatus, setCopyStatus] = useState("Copy");
  const copySource = async () => {
    try {
      await navigator.clipboard.writeText(source);
      setCopyStatus("Copied");
    } catch {
      setCopyStatus("Select and copy");
    }
  };
  return <figure className="latex-source">
      <figcaption className="latex-source__header">
        <span className="latex-source__filename">{filename}</span>
        <button type="button" className="latex-source__copy" onClick={copySource} aria-live="polite">
          {copyStatus}
        </button>
      </figcaption>
      <pre className="latex-source__pre" aria-label={`LaTeX source: ${filename}`} tabIndex="0">
        <code className="language-latex">{source}</code>
      </pre>
    </figure>;
};

export const LatexPreview = ({src, alt, caption, width, height}) => {
  const minZoom = 1;
  const maxZoom = 3;
  const zoomStep = 0.5;
  const measureSvgContent = async (assetSrc, pageWidth, pageHeight) => {
    const cacheKey = "__latexCloudSvgContentBoxCache";
    const contentBoxCache = globalThis[cacheKey] ?? new Map();
    globalThis[cacheKey] = contentBoxCache;
    if (contentBoxCache.has(assetSrc)) return contentBoxCache.get(assetSrc);
    const measurement = (async () => {
      const assetUrl = new URL(assetSrc, window.location.href);
      if (assetUrl.origin !== window.location.origin) {
        throw new Error("Rendered output must use a same-origin SVG asset.");
      }
      const response = await fetch(assetUrl, {
        credentials: "same-origin"
      });
      if (!response.ok) throw new Error(`Rendered output request failed with ${response.status}.`);
      const source = await response.text();
      const documentNode = new DOMParser().parseFromString(source, "image/svg+xml");
      if (documentNode.querySelector("parsererror")) throw new Error("Rendered output is not valid SVG.");
      const sourceSvg = documentNode.documentElement;
      sourceSvg.querySelectorAll("script, foreignObject").forEach(node => node.remove());
      [sourceSvg, ...sourceSvg.querySelectorAll("*")].forEach(node => {
        [...node.attributes].forEach(attribute => {
          if ((/^on/i).test(attribute.name)) node.removeAttribute(attribute.name);
          if ((attribute.name === "href" || attribute.name === "xlink:href") && !attribute.value.startsWith("#")) {
            node.removeAttribute(attribute.name);
          }
        });
      });
      const measurementHost = document.createElement("div");
      measurementHost.className = "latex-preview__measurement-host";
      const measuredSvg = document.importNode(sourceSvg, true);
      measuredSvg.setAttribute("aria-hidden", "true");
      measurementHost.appendChild(measuredSvg);
      document.body.appendChild(measurementHost);
      try {
        const measuredElements = [...measuredSvg.children].filter(node => !["defs", "desc", "metadata", "style", "title"].includes(node.tagName.toLowerCase()));
        const elementBounds = measuredElements.map(node => node.getBBox()).filter(box => [box.x, box.y, box.width, box.height].every(Number.isFinite) && box.width > 0 && box.height > 0);
        if (elementBounds.length === 0) {
          throw new Error("Rendered output has no measurable visible content.");
        }
        const sortedBounds = [...elementBounds].sort((left, right) => left.y - right.y);
        const clusterGap = pageHeight * 0.045;
        const clusters = [];
        sortedBounds.forEach(box => {
          const current = clusters[clusters.length - 1];
          if (!current || box.y - current.bottom > clusterGap) {
            clusters.push({
              boxes: [box],
              bottom: box.y + box.height
            });
            return;
          }
          current.boxes.push(box);
          current.bottom = Math.max(current.bottom, box.y + box.height);
        });
        const contentClusters = clusters.filter(cluster => {
          const clusterBox = cluster.boxes.reduce((combined, box) => {
            const right = Math.max(combined.x + combined.width, box.x + box.width);
            const bottom = Math.max(combined.y + combined.height, box.y + box.height);
            const x = Math.min(combined.x, box.x);
            const y = Math.min(combined.y, box.y);
            return {
              x,
              y,
              width: right - x,
              height: bottom - y
            };
          });
          const centerY = clusterBox.y + clusterBox.height / 2;
          const isMarginFurniture = cluster.boxes.length <= 2 && clusterBox.width < pageWidth * 0.2 && clusterBox.height < pageHeight * 0.04 && (centerY < pageHeight * 0.08 || centerY > pageHeight * 0.8);
          return !isMarginFurniture;
        });
        const visibleBounds = (contentClusters.length > 0 ? contentClusters : clusters).flatMap(cluster => cluster.boxes);
        const bounds = visibleBounds.reduce((combined, box) => {
          const right = Math.max(combined.x + combined.width, box.x + box.width);
          const bottom = Math.max(combined.y + combined.height, box.y + box.height);
          const x = Math.min(combined.x, box.x);
          const y = Math.min(combined.y, box.y);
          return {
            x,
            y,
            width: right - x,
            height: bottom - y
          };
        });
        const clampValue = (value, minimum, maximum) => Math.min(maximum, Math.max(minimum, value));
        const padding = Math.max(8, Math.min(pageWidth, pageHeight) * 0.025);
        const x = clampValue(bounds.x - padding, 0, pageWidth);
        const y = clampValue(bounds.y - padding, 0, pageHeight);
        const right = clampValue(bounds.x + bounds.width + padding, 0, pageWidth);
        const bottom = clampValue(bounds.y + bounds.height + padding, 0, pageHeight);
        return {
          x,
          y,
          width: right - x,
          height: bottom - y
        };
      } finally {
        measurementHost.remove();
      }
    })();
    contentBoxCache.set(assetSrc, measurement);
    measurement.catch(() => contentBoxCache.delete(assetSrc));
    return measurement;
  };
  const renderPreviewAsset = ({contentBox: assetContentBox, loading}) => {
    if (!assetContentBox) {
      return <img className="latex-preview__asset" src={src} alt={alt} width={width} height={height} loading={loading} draggable="false" />;
    }
    return <svg className="latex-preview__asset" viewBox={`${assetContentBox.x} ${assetContentBox.y} ${assetContentBox.width} ${assetContentBox.height}`} preserveAspectRatio="xMidYMid meet" role="img" aria-label={alt}>
        <image href={src} x="0" y="0" width={width} height={height} />
      </svg>;
  };
  const [isOpen, setIsOpen] = useState(false);
  const [frameMode, setFrameMode] = useState("content");
  const [viewMode, setViewMode] = useState("fit");
  const [zoom, setZoom] = useState(minZoom);
  const [contentBox, setContentBox] = useState(null);
  const [measurementStatus, setMeasurementStatus] = useState("loading");
  const dialogRef = useRef(null);
  const closeButtonRef = useRef(null);
  const viewportRef = useRef(null);
  const previousFocusRef = useRef(null);
  const dragRef = useRef(null);
  useEffect(() => {
    let isCurrent = true;
    setMeasurementStatus("loading");
    measureSvgContent(src, width, height).then(box => {
      if (!isCurrent) return;
      setContentBox(box);
      setMeasurementStatus("ready");
    }).catch(() => {
      if (!isCurrent) return;
      setContentBox(null);
      setFrameMode("page");
      setMeasurementStatus("error");
    });
    return () => {
      isCurrent = false;
    };
  }, [height, src, width]);
  const closeViewer = useCallback(() => {
    setIsOpen(false);
  }, []);
  const openViewer = () => {
    previousFocusRef.current = document.activeElement;
    setFrameMode(contentBox ? "content" : "page");
    setViewMode("fit");
    setZoom(minZoom);
    setIsOpen(true);
  };
  const applyZoom = useCallback(nextZoom => {
    const boundedZoom = Math.min(maxZoom, Math.max(minZoom, nextZoom));
    setViewMode("custom");
    setZoom(boundedZoom);
  }, []);
  const zoomIn = useCallback(() => {
    applyZoom(viewMode === "fit" ? minZoom + zoomStep : zoom + zoomStep);
  }, [applyZoom, viewMode, zoom]);
  const zoomOut = useCallback(() => {
    applyZoom(viewMode === "fit" ? minZoom : zoom - zoomStep);
  }, [applyZoom, viewMode, zoom]);
  useEffect(() => {
    if (!isOpen) return undefined;
    const previousOverflow = document.body.style.overflow;
    document.body.style.overflow = "hidden";
    closeButtonRef.current?.focus();
    return () => {
      document.body.style.overflow = previousOverflow;
      previousFocusRef.current?.focus?.();
    };
  }, [isOpen]);
  useEffect(() => {
    if (!isOpen) return undefined;
    const handleKeyDown = event => {
      if (event.key === "Escape") {
        event.preventDefault();
        closeViewer();
        return;
      }
      if ((event.key === "+" || event.key === "=") && !event.metaKey && !event.ctrlKey) {
        event.preventDefault();
        zoomIn();
        return;
      }
      if (event.key === "-" && !event.metaKey && !event.ctrlKey) {
        event.preventDefault();
        zoomOut();
        return;
      }
      if (event.key !== "Tab" || !dialogRef.current) return;
      const focusable = [...dialogRef.current.querySelectorAll('button:not([disabled]), a[href], [tabindex]:not([tabindex="-1"])')];
      if (focusable.length === 0) return;
      const first = focusable[0];
      const last = focusable[focusable.length - 1];
      if (event.shiftKey && document.activeElement === first) {
        event.preventDefault();
        last.focus();
      } else if (!event.shiftKey && document.activeElement === last) {
        event.preventDefault();
        first.focus();
      }
    };
    window.addEventListener("keydown", handleKeyDown);
    return () => {
      window.removeEventListener("keydown", handleKeyDown);
    };
  }, [closeViewer, isOpen, zoomIn, zoomOut]);
  const startDrag = event => {
    if (event.button !== 0 || !viewportRef.current) return;
    const viewport = viewportRef.current;
    dragRef.current = {
      pointerId: event.pointerId,
      x: event.clientX,
      y: event.clientY,
      scrollLeft: viewport.scrollLeft,
      scrollTop: viewport.scrollTop
    };
    viewport.setPointerCapture(event.pointerId);
    viewport.dataset.dragging = "true";
  };
  const continueDrag = event => {
    const drag = dragRef.current;
    const viewport = viewportRef.current;
    if (!drag || !viewport || drag.pointerId !== event.pointerId) return;
    viewport.scrollLeft = drag.scrollLeft - (event.clientX - drag.x);
    viewport.scrollTop = drag.scrollTop - (event.clientY - drag.y);
  };
  const stopDrag = event => {
    const viewport = viewportRef.current;
    if (viewport?.hasPointerCapture(event.pointerId)) viewport.releasePointerCapture(event.pointerId);
    if (viewport) delete viewport.dataset.dragging;
    dragRef.current = null;
  };
  const activeContentBox = frameMode === "content" ? contentBox : null;
  const activeWidth = activeContentBox?.width ?? width;
  const activeHeight = activeContentBox?.height ?? height;
  const activeRatio = activeWidth / activeHeight;
  const inlineContentBox = measurementStatus === "ready" ? contentBox : null;
  const inlineWidth = inlineContentBox?.width ?? width;
  const inlineHeight = inlineContentBox?.height ?? height;
  const inlineGeometry = {
    aspectRatio: `${inlineWidth} / ${inlineHeight}`,
    maxWidth: `${30 * inlineWidth / inlineHeight}rem`
  };
  const imageStyle = viewMode === "fit" ? {
    aspectRatio: `${activeWidth} / ${activeHeight}`,
    width: "100%",
    maxWidth: `${Math.max(16, activeRatio * 78)}dvh`
  } : {
    aspectRatio: `${activeWidth} / ${activeHeight}`,
    width: `${zoom * 100}%`,
    maxWidth: "none"
  };
  const zoomLabel = viewMode === "fit" ? frameMode === "content" ? "Fit content" : "Full page" : `${Math.round(zoom * 100)}%`;
  return <figure className="latex-preview">
      <button type="button" className="latex-preview__trigger" onClick={openViewer} aria-haspopup="dialog" aria-label={`Open zoomable preview: ${alt}`}>
        <span className="latex-preview__page" style={inlineGeometry}>
          {measurementStatus === "loading" ? <span className="latex-preview__loading" role="status">Preparing compiled output…</span> : renderPreviewAsset({
    src,
    alt,
    width,
    height,
    contentBox: inlineContentBox,
    loading: "lazy"
  })}
        </span>
        <span className="latex-preview__trigger-label" aria-hidden="true">
          <span className="latex-preview__trigger-icon">⌕</span>
          Open viewer
        </span>
      </button>
      <figcaption className="latex-preview__caption">
        <span>
          {caption}
          {measurementStatus === "error" && <span className="latex-preview__status" role="status"> Content fit is unavailable; the complete vector page is shown.</span>}
        </span>
        <a href={src} target="_blank" rel="noreferrer" className="latex-preview__source-link">Open SVG</a>
      </figcaption>

      {isOpen && <div className="latex-preview__backdrop" onMouseDown={event => {
    if (event.target === event.currentTarget) closeViewer();
  }}>
          <section ref={dialogRef} className="latex-preview__dialog" role="dialog" aria-modal="true" aria-label={`Rendered LaTeX viewer: ${alt}`}>
            <header className="latex-preview__toolbar">
              <div className="latex-preview__identity">
                <span className="latex-preview__eyebrow">Compiled LaTeX</span>
                <span className="latex-preview__filename">{alt}</span>
              </div>
              <div className="latex-preview__controls" aria-label="Preview controls">
                <button type="button" className={frameMode === "content" && viewMode === "fit" ? "is-active" : undefined} disabled={!contentBox} onClick={() => {
    setFrameMode("content");
    setViewMode("fit");
    setZoom(minZoom);
  }}>
                  Fit content
                </button>
                <button type="button" className={frameMode === "page" && viewMode === "fit" ? "is-active" : undefined} onClick={() => {
    setFrameMode("page");
    setViewMode("fit");
    setZoom(minZoom);
  }}>
                  Full page
                </button>
                <span className="latex-preview__zoom-group">
                  <button type="button" onClick={zoomOut} disabled={viewMode === "fit" || zoom <= minZoom} aria-label="Zoom out">−</button>
                  <output aria-live="polite" aria-label="Current zoom">{zoomLabel}</output>
                  <button type="button" onClick={zoomIn} disabled={viewMode !== "fit" && zoom >= maxZoom} aria-label="Zoom in">+</button>
                </span>
                <a href={src} target="_blank" rel="noreferrer">Open SVG</a>
                <button ref={closeButtonRef} type="button" className="latex-preview__close" onClick={closeViewer} aria-label="Close rendered LaTeX viewer">
                  Close
                </button>
              </div>
            </header>
            <div ref={viewportRef} className="latex-preview__viewport" data-view-mode={viewMode} onPointerDown={startDrag} onPointerMove={continueDrag} onPointerUp={stopDrag} onPointerCancel={stopDrag}>
              <span className="latex-preview__dialog-page" style={imageStyle}>
                {renderPreviewAsset({
    src,
    alt,
    width,
    height,
    contentBox: activeContentBox
  })}
              </span>
            </div>
            <footer className="latex-preview__viewer-note">
              Compiler-generated vector output · Use +/− to zoom · Drag to pan · Esc to close
            </footer>
          </section>
        </div>}
    </figure>;
};

A LaTeX compiler (also called an engine) transforms your `.tex` source files into the final output format (usually PDF). Understanding the differences between compilers helps you choose the right tool for your project.

<Info>
  **In LaTeX Cloud Studio**: We handle compiler selection automatically, but you can switch between engines in your document settings for specific needs.
</Info>

## What is a LaTeX Compiler?

A LaTeX compiler:

1. **Reads** your source file (.tex)
2. **Processes** all commands and content
3. **Generates** output (PDF, DVI, etc.)
4. **Reports** any errors or warnings

Think of it as a translator that converts your human-readable LaTeX code into a beautifully formatted document.

## Main LaTeX Compilers

### pdfLaTeX (Default Choice)

The most common and widely-supported compiler.

**Pros:**

* Fast compilation
* Excellent compatibility
* Mature and stable
* Supports most packages
* Default in most systems

**Cons:**

* Limited to 8-bit fonts
* No direct Unicode support
* Can't use system fonts

**Best for:**

* Most documents
* Academic papers
* When compatibility matters
* Beginning LaTeX users

<LatexSource filename="pdflatex-example.tex" source={"\\documentclass{article}\n\\usepackage[utf8]{inputenc} % Needed for special characters\n\\usepackage[T1]{fontenc}     % Better font encoding\n\n\\begin{document}\nThis document compiles perfectly with pdfLaTeX!\n\\end{document}"} />

<RenderedOutput title="Rendered output" ctaHref="https://app.latex-cloud-studio.com/?utm_source=resources&utm_medium=rendered_output&utm_campaign=docs_open_app&utm_content=learn_latex_basics_choosing_compiler">
  <LatexPreview src="/images/rendered/learn-latex-basics-choosing-compiler-01/page-1.svg" alt="Compiled PDF page 1 from pdflatex-example.tex" caption="Generated from the shown source with pdfLaTeX in the pinned LaTeXCloud TeX Live 2026 environment." width={595.276} height={841.89} />
</RenderedOutput>

### XeLaTeX (Modern Typography)

A modern engine with excellent font support.

**Pros:**

* Full Unicode support
* Use any system font
* Better multilingual support
* Advanced typography features
* Handles complex scripts

**Cons:**

* Slower compilation
* Some packages incompatible
* Larger file sizes

**Best for:**

* Documents with special fonts
* Multilingual documents
* Non-Latin scripts
* Typography-focused work

<LatexSource filename="xelatex-example.tex" source={"\\documentclass{article}\n\\usepackage{fontspec} % XeLaTeX font selection\n\n% Use any font installed on your system\n\\setmainfont{Helvetica Neue}\n\\setsansfont{Arial}\n\\setmonofont{Consolas}\n\n\\begin{document}\nXeLaTeX lets you use any font: English, 中文, العربية, ελληνικά!\n\\end{document}"} />

<RenderedOutput title="Expected effect">
  <Info>
    This example configures a system font. The visible result depends on fonts installed in the reader's compilation environment, so the code box describes the intended configuration instead of showing a misleading substitute font.
  </Info>
</RenderedOutput>

### LuaLaTeX (Programmable Power)

The newest engine with embedded Lua scripting.

**Pros:**

* Full Unicode support
* Lua scripting capability
* Modern font handling
* Microtype improvements
* Active development

**Cons:**

* Slowest compilation
* Newest (less documentation)
* Some compatibility issues

**Best for:**

* Complex programmatic documents
* Advanced typography
* When you need scripting
* Future-proof projects

<LatexSource filename="lualatex-example.tex" source={"\\documentclass{article}\n\\usepackage{fontspec}\n\\usepackage{luacode}\n\n\\begin{document}\nLuaLaTeX can execute Lua code:\n\n\\begin{luacode}\nfor i = 1, 5 do\n    tex.print(\"Line \" .. i .. \"\\\\\\\\\")\nend\n\\end{luacode}\n\\end{document}"} />

<RenderedOutput title="Rendered output">
  <LatexPreview src="/images/rendered/learn-latex-basics-choosing-compiler-03/page-1.svg" alt="Compiled PDF page 1 from lualatex-example.tex" caption="Generated from the shown source with LuaLaTeX in the pinned LaTeXCloud TeX Live 2026 environment." width={595.276} height={841.89} />
</RenderedOutput>

## Comparison Table

| Feature            | pdfLaTeX  | XeLaTeX   | LuaLaTeX  |
| ------------------ | --------- | --------- | --------- |
| **Speed**          | Fast ⚡⚡⚡  | Medium ⚡⚡ | Slow ⚡    |
| **Unicode**        | Limited   | Full ✓    | Full ✓    |
| **System Fonts**   | No ✗      | Yes ✓     | Yes ✓     |
| **Compatibility**  | Excellent | Good      | Good      |
| **Scripting**      | No        | No        | Lua ✓     |
| **Memory Usage**   | Low       | Medium    | High      |
| **Output Quality** | Excellent | Excellent | Excellent |

## How to Choose

### Use pdfLaTeX when:

* You're just starting with LaTeX
* Writing standard academic documents
* Need maximum compatibility
* Want fastest compilation
* Using traditional LaTeX packages

### Use XeLaTeX when:

* Need specific fonts (corporate branding)
* Writing in multiple languages
* Using non-Latin scripts
* Want OpenType font features
* Typography is crucial

### Use LuaLaTeX when:

* Need programmatic document generation
* Want the latest features
* Require advanced typography
* Can accept slower compilation
* Building complex automated documents

## Compiler-Specific Commands

### Checking Your Compiler

You can make your document adapt to different compilers:

<LatexSource filename="compiler-check.tex" source={"\\documentclass{article}\n\n% Load appropriate packages based on compiler\n\\usepackage{ifxetex,ifluatex}\n\\ifxetex\n    \\usepackage{fontspec}\n    \\newcommand{\\mycompiler}{XeLaTeX}\n\\else\\ifluatex\n    \\usepackage{fontspec}\n    \\newcommand{\\mycompiler}{LuaLaTeX}\n\\else\n    \\usepackage[utf8]{inputenc}\n    \\usepackage[T1]{fontenc}\n    \\newcommand{\\mycompiler}{pdfLaTeX}\n\\fi\\fi\n\n\\begin{document}\nThis document was compiled with \\mycompiler.\n\\end{document}"} />

<RenderedOutput title="Rendered output">
  <LatexPreview src="/images/rendered/learn-latex-basics-choosing-compiler-04/page-1.svg" alt="Compiled PDF page 1 from compiler-check.tex" caption="Generated from the shown source with XeLaTeX in the pinned LaTeXCloud TeX Live 2026 environment." width={595.28} height={841.89} />
</RenderedOutput>

### Font Selection by Compiler

<LatexSource filename="font-selection.tex" source={"\\documentclass{article}\n\\usepackage{ifxetex,ifluatex}\n\n% Modern font setup for XeLaTeX/LuaLaTeX\n\\ifxetex\\else\\ifluatex\\else\n    % pdfLaTeX font setup\n    \\usepackage[T1]{fontenc}\n    \\usepackage{lmodern} % Latin Modern fonts\n\\fi\\fi\n\n\\ifxetex\n    \\usepackage{fontspec}\n    \\setmainfont{Times New Roman}\n\\else\\ifluatex\n    \\usepackage{fontspec}\n    \\setmainfont{Times New Roman}\n\\fi\\fi\n\n\\begin{document}\nFonts work correctly regardless of compiler!\n\\end{document}"} />

<RenderedOutput title="Rendered output">
  <LatexPreview src="/images/rendered/learn-latex-basics-choosing-compiler-05/page-1.svg" alt="Compiled PDF page 1 from font-selection.tex" caption="Generated from the shown source with XeLaTeX in the pinned LaTeXCloud TeX Live 2026 environment." width={595.28} height={841.89} />
</RenderedOutput>

## Special Use Cases

### Mathematical Documents

**Recommended**: pdfLaTeX

* Best package support
* Fast compilation
* All math packages work

### Multilingual Documents

**Recommended**: XeLaTeX

* Full Unicode support
* Easy font switching
* Proper script handling

### Presentations

**Recommended**: pdfLaTeX with Beamer

* Fast compilation for iterations
* Full Beamer compatibility
* Reliable output

### Books with Custom Fonts

**Recommended**: XeLaTeX or LuaLaTeX

* Professional typography
* Font flexibility
* Advanced features

## In LaTeX Cloud Studio

LaTeX Cloud Studio makes compiler selection easy:

1. **Automatic Detection**: We analyze your document and suggest the best compiler
2. **Easy Switching**: Change compilers in document settings
3. **Error Handling**: Clear messages if packages need a different compiler
4. **Preconfiqured**: All compilers are ready to use

### Setting Compiler in Your Document

You can specify your preferred compiler using a magic comment:

<LatexSource filename="example.tex" source={"% !TEX program = xelatex\n\\documentclass{article}\n\\usepackage{fontspec}\n..."} />

<RenderedOutput title="Expected effect">
  <Info>
    This is document setup or preamble code. It changes the behavior of a containing document but does not produce an honest standalone page by itself.
  </Info>
</RenderedOutput>

## Troubleshooting Compiler Issues

<Warning>
  **Common compiler-related errors:**

  1. **"Package requires XeLaTeX/LuaLaTeX"**
     * Switch to the appropriate compiler
     * Or use alternative packages

  2. **"Unicode character not set up"**
     * Use XeLaTeX/LuaLaTeX for full Unicode
     * Or add `\usepackage[utf8]{inputenc}` for pdfLaTeX

  3. **"Font not found"**
     * System fonts need XeLaTeX/LuaLaTeX
     * Or use LaTeX font packages with pdfLaTeX
</Warning>

## Migration Guide

### From pdfLaTeX to XeLaTeX

Remove these packages:

<LatexSource filename="example.tex" source={"% Remove these:\n\\usepackage[utf8]{inputenc}\n\\usepackage[T1]{fontenc}\n\n% Add this:\n\\usepackage{fontspec}"} />

<RenderedOutput title="Expected effect">
  <Info>
    This is setup or structural LaTeX code. It changes available commands or document behavior, but it does not produce meaningful standalone page content by itself.
  </Info>
</RenderedOutput>

### From XeLaTeX to pdfLaTeX

Replace font commands:

<LatexSource filename="example.tex" source={"% Remove:\n\\setmainfont{Arial}\n\n% Add:\n\\usepackage{helvet}\n\\renewcommand{\\familydefault}{\\sfdefault}"} />

<RenderedOutput title="Expected effect">
  <Info>
    This code is a contextual or intentionally partial LaTeX excerpt, not a self-contained compilable document. Its visible result depends on the surrounding document, so the documentation shows the expected role without inventing a standalone preview.
  </Info>
</RenderedOutput>

## Performance Tips

<Tip>
  **Speed up compilation:**

  1. Use pdfLaTeX for drafts
  2. Switch to XeLaTeX/LuaLaTeX for final version
  3. Enable draft mode: `\documentclass[draft]{article}`
  4. Compile only changed parts during writing
  5. Use LaTeX Cloud Studio's incremental compilation
</Tip>

## Quick Decision Chart

```
Need special fonts? ──> Yes ──> XeLaTeX
         │
         No
         │
         ▼
Need Unicode? ──> Yes ──> XeLaTeX/LuaLaTeX
         │
         No
         │
         ▼
Need scripting? ──> Yes ──> LuaLaTeX
         │
         No
         │
         ▼
    pdfLaTeX (Best default choice)
```

## Summary

* **Start with pdfLaTeX** - It's fast and compatible
* **Switch to XeLaTeX** - When you need fonts or languages
* **Try LuaLaTeX** - For advanced programmable documents

Remember: All compilers produce high-quality output. The differences are mainly about features and speed, not quality.

***

<Info>
  **Next step**: Learn about [Paragraphs and new lines](/learn/latex/basics/paragraphs-new-lines) to structure your content effectively.
</Info>