diff --git a/modules/common/src/main/scala/docspell/common/File.scala b/modules/common/src/main/scala/docspell/common/File.scala
index 41884949..006f9098 100644
--- a/modules/common/src/main/scala/docspell/common/File.scala
+++ b/modules/common/src/main/scala/docspell/common/File.scala
@@ -17,6 +17,9 @@ object File {
   def mkTempDir[F[_]: Sync](parent: Path, prefix: String): F[Path] =
     mkDir(parent).map(p => Files.createTempDirectory(p, prefix))
 
+  def mkTempFile[F[_]: Sync](parent: Path, prefix: String, suffix: Option[String] = None): F[Path] =
+    mkDir(parent).map(p => Files.createTempFile(p, prefix, suffix.orNull))
+
   def deleteDirectory[F[_]: Sync](dir: Path): F[Int] = Sync[F].delay {
     val count = new AtomicInteger(0)
     Files.walkFileTree(
diff --git a/modules/common/src/main/scala/docspell/common/SystemCommand.scala b/modules/common/src/main/scala/docspell/common/SystemCommand.scala
index cfa2ab33..4f93d87a 100644
--- a/modules/common/src/main/scala/docspell/common/SystemCommand.scala
+++ b/modules/common/src/main/scala/docspell/common/SystemCommand.scala
@@ -1,12 +1,15 @@
 package docspell.common
 
 import java.io.InputStream
+import java.lang.ProcessBuilder.Redirect
 import java.nio.file.Path
 import java.util.concurrent.TimeUnit
+
 import cats.implicits._
 import cats.effect.{Blocker, ContextShift, Sync}
 import fs2.{Stream, io, text}
 import org.log4s.getLogger
+
 import scala.jdk.CollectionConverters._
 import docspell.common.syntax.all._
 
@@ -33,7 +36,7 @@ object SystemCommand {
       wd: Option[Path] = None,
       stdin: Stream[F, Byte] = Stream.empty
   ): Stream[F, Result] =
-    startProcess(cmd, wd) { proc =>
+    startProcess(cmd, wd, stdin) { proc =>
       Stream.eval {
         for {
           _    <- writeToProcess(stdin, proc, blocker)
@@ -66,15 +69,20 @@ object SystemCommand {
       else Stream.emit(r)
     }
 
-  private def startProcess[F[_]: Sync, A](cmd: Config, wd: Option[Path])(
+  private def startProcess[F[_]: Sync, A](cmd: Config, wd: Option[Path], stdin: Stream[F, Byte])(
       f: Process => Stream[F, A]
   ): Stream[F, A] = {
     val log = logger.fdebug(s"Running external command: ${cmd.cmdString}")
-    val proc = log *> Sync[F].delay {
+    val hasStdin = stdin.take(1).compile.last.map(_.isDefined)
+    val proc = log *> hasStdin.flatMap(flag => Sync[F].delay {
       val pb = new ProcessBuilder(cmd.toCmd.asJava)
+        .redirectInput(if (flag) Redirect.PIPE else Redirect.INHERIT)
+        .redirectError(Redirect.PIPE)
+        .redirectOutput(Redirect.PIPE)
+
       wd.map(_.toFile).foreach(pb.directory)
       pb.start()
-    }
+    })
     Stream
       .bracket(proc)(p =>
         logger.fdebug(s"Closing process: `${cmd.cmdString}`").map { _ =>
diff --git a/modules/convert/src/main/scala/docspell/convert/extern/ExternConv.scala b/modules/convert/src/main/scala/docspell/convert/extern/ExternConv.scala
new file mode 100644
index 00000000..a45f7b22
--- /dev/null
+++ b/modules/convert/src/main/scala/docspell/convert/extern/ExternConv.scala
@@ -0,0 +1,108 @@
+package docspell.convert.extern
+
+import java.nio.file.Path
+
+import cats.effect._
+import fs2.{Pipe, Stream}
+import docspell.common._
+
+object ExternConv {
+
+  def toPDF[F[_]: Sync: ContextShift](
+      name: String,
+      cmdCfg: SystemCommand.Config,
+      wd: Path,
+      chunkSize: Int,
+      blocker: Blocker,
+      logger: Logger[F]
+  ): Pipe[F, Byte, Byte] =
+    in =>
+      Stream.resource(File.withTempDir[F](wd, s"docspell-$name")).flatMap { dir =>
+        val out = dir.resolve("out.pdf")
+        val sysCfg =
+          cmdCfg.mapArgs(_.replace("{{outfile}}", out.toAbsolutePath.normalize.toString))
+
+        SystemCommand
+          .execSuccess[F](sysCfg, blocker, Some(dir), in)
+          .flatMap(result =>
+            logResult(name, result, logger) ++ readResult[F](
+              out,
+              result,
+              blocker,
+              chunkSize,
+              logger
+            )
+          )
+      }
+
+  def toPDFviaFile[F[_]: Sync: ContextShift](
+      name: String,
+      cmdCfg: SystemCommand.Config,
+      wd: Path,
+      chunkSize: Int,
+      blocker: Blocker,
+      logger: Logger[F]
+  ): Pipe[F, Byte, Byte] =
+    in =>
+      Stream.resource(File.withTempDir[F](wd, s"docspell-$name")).flatMap { dir =>
+        val inFile = dir.resolve("infile")
+        val out    = dir.resolve("out.pdf")
+        val sysCfg =
+          cmdCfg.mapArgs(
+            _.replace("{{outfile}}", out.toAbsolutePath.normalize.toString)
+              .replace("{{infile}}", inFile.toAbsolutePath.normalize.toString)
+          )
+
+        (Stream.eval(logger.debug(s"Storing input to file ${inFile} for running $name")).drain ++
+          Stream.eval(storeFile(in, inFile, blocker))).flatMap { _ =>
+          SystemCommand
+            .execSuccess[F](sysCfg, blocker, Some(dir))
+            .flatMap(result =>
+              logResult(name, result, logger) ++ readResult[F](
+                out,
+                result,
+                blocker,
+                chunkSize,
+                logger
+              )
+            )
+        }
+      }
+
+  private def readResult[F[_]: Sync: ContextShift](
+      out: Path,
+      result: SystemCommand.Result,
+      blocker: Blocker,
+      chunkSize: Int,
+      logger: Logger[F]
+  ): Stream[F, Byte] =
+    Stream.eval(File.existsNonEmpty[F](out)).flatMap {
+      case true =>
+        if (result.rc == 0) File.readAll(out, blocker, chunkSize)
+        else
+          Stream
+            .eval(logger.warn(s"Command not successful (rc=${result.rc}), but file exists."))
+            .drain ++
+            File.readAll(out, blocker, chunkSize)
+
+      case false =>
+        Stream.raiseError[F](
+          new Exception(s"Command result=${result.rc}. No output file found.")
+        )
+    }
+
+  private def logResult[F[_]: Sync](
+      name: String,
+      result: SystemCommand.Result,
+      logger: Logger[F]
+  ): Stream[F, Nothing] =
+    Stream.eval(logger.debug(s"$name stdout: ${result.stdout}")).drain ++
+      Stream.eval(logger.debug(s"$name stderr: ${result.stderr}")).drain
+
+  private def storeFile[F[_]: Sync: ContextShift](
+    in: Stream[F, Byte],
+      target: Path,
+      blocker: Blocker
+  ): F[Unit] =
+    in.through(fs2.io.file.writeAll(target, blocker)).compile.drain
+}
diff --git a/modules/convert/src/main/scala/docspell/convert/extern/Unoconv.scala b/modules/convert/src/main/scala/docspell/convert/extern/Unoconv.scala
new file mode 100644
index 00000000..ee2256d9
--- /dev/null
+++ b/modules/convert/src/main/scala/docspell/convert/extern/Unoconv.scala
@@ -0,0 +1,18 @@
+package docspell.convert.extern
+
+import cats.effect._
+import fs2.Pipe
+import docspell.common._
+
+object Unoconv {
+
+  def toPDF[F[_]: Sync: ContextShift](
+      cfg: UnoconvConfig,
+      chunkSize: Int,
+      blocker: Blocker,
+      logger: Logger[F],
+  ): Pipe[F, Byte, Byte] =
+    ExternConv.toPDFviaFile[F]("unoconv", cfg.cmd, cfg.workingDir, chunkSize, blocker, logger)
+
+
+}
diff --git a/modules/convert/src/main/scala/docspell/convert/extern/UnoconvConfig.scala b/modules/convert/src/main/scala/docspell/convert/extern/UnoconvConfig.scala
new file mode 100644
index 00000000..da4af43c
--- /dev/null
+++ b/modules/convert/src/main/scala/docspell/convert/extern/UnoconvConfig.scala
@@ -0,0 +1,7 @@
+package docspell.convert.extern
+
+import java.nio.file.Path
+
+import docspell.common.SystemCommand
+
+case class UnoconvConfig (cmd: SystemCommand.Config, workingDir: Path)
diff --git a/modules/convert/src/main/scala/docspell/convert/extern/WkHtmlPdf.scala b/modules/convert/src/main/scala/docspell/convert/extern/WkHtmlPdf.scala
index 60fa1fb9..d736c474 100644
--- a/modules/convert/src/main/scala/docspell/convert/extern/WkHtmlPdf.scala
+++ b/modules/convert/src/main/scala/docspell/convert/extern/WkHtmlPdf.scala
@@ -1,9 +1,7 @@
 package docspell.convert.extern
 
-import java.nio.file.Path
-
 import cats.effect._
-import fs2.{Pipe, Stream}
+import fs2.Pipe
 import docspell.common._
 
 object WkHtmlPdf {
@@ -12,39 +10,9 @@ object WkHtmlPdf {
       cfg: WkHtmlPdfConfig,
       chunkSize: Int,
       blocker: Blocker,
-      logger: Logger[F]
+      logger: Logger[F],
   ): Pipe[F, Byte, Byte] =
-    in =>
-      Stream.resource(File.withTempDir[F](cfg.workingDir, "docspell-wkhtmltopdf")).flatMap { dir =>
-        val out = dir.resolve("out.pdf")
-        val sysCfg =
-          cfg.cmd.mapArgs(_.replace("{{outfile}}", out.toAbsolutePath.normalize.toString))
+    ExternConv.toPDF[F]("wkhtmltopdf", cfg.cmd, cfg.workingDir, chunkSize, blocker, logger)
 
-        Stream.eval(logger.info(s"Running ${sysCfg.program}")).drain ++
-          SystemCommand
-            .execSuccess[F](sysCfg, blocker, Some(dir), in)
-            .flatMap(result => readResult[F](out, result, blocker, chunkSize, logger))
-      }
 
-  private def readResult[F[_]: Sync: ContextShift](
-      out: Path,
-      result: SystemCommand.Result,
-      blocker: Blocker,
-      chunkSize: Int,
-      logger: Logger[F]
-  ): Stream[F, Byte] =
-    Stream.eval(File.existsNonEmpty[F](out)).flatMap {
-      case true =>
-        if (result.rc == 0) File.readAll(out, blocker, chunkSize)
-        else
-          Stream
-            .eval(logger.warn(s"Command not successful (rc=${result.rc}), but file exists."))
-            .drain ++
-            File.readAll(out, blocker, chunkSize)
-
-      case false =>
-        Stream.raiseError(
-          new Exception(s"Command result=${result.rc}. No output file found. ${result.stderr}")
-        )
-    }
 }
diff --git a/modules/convert/src/main/scala/docspell/convert/flexmark/Markdown.scala b/modules/convert/src/main/scala/docspell/convert/flexmark/Markdown.scala
index 94b32811..f895e44f 100644
--- a/modules/convert/src/main/scala/docspell/convert/flexmark/Markdown.scala
+++ b/modules/convert/src/main/scala/docspell/convert/flexmark/Markdown.scala
@@ -40,8 +40,10 @@ object Markdown {
       map(str => toHtml(str, cfg))
 
   private def wrapHtml(body: String, cfg: MarkdownConfig): String = {
-    s"""<html>
+    s"""<!DOCTYPE html>
+       |<html>
        |<head>
+       |<meta charset="utf-8"/>
        |<style>
        |${cfg.internalCss}
        |</style>
diff --git a/modules/convert/src/test/scala/docspell/convert/extern/ExternConvTest.scala b/modules/convert/src/test/scala/docspell/convert/extern/ExternConvTest.scala
new file mode 100644
index 00000000..7f81b694
--- /dev/null
+++ b/modules/convert/src/test/scala/docspell/convert/extern/ExternConvTest.scala
@@ -0,0 +1,80 @@
+package docspell.convert.extern
+
+import java.nio.file.{Files, Path, Paths}
+
+import fs2.Stream
+import cats.effect._
+import docspell.common._
+import docspell.files.{ExampleFiles, TestFiles}
+import fs2.Pipe
+import minitest.SimpleTestSuite
+
+object ExternConvTest extends SimpleTestSuite {
+  val blocker     = TestFiles.blocker
+  implicit val CS = TestFiles.CS
+
+  val logger = Logger.log4s[IO](org.log4s.getLogger)
+  val target = Paths.get("target")
+
+
+  test("convert html to pdf") {
+    val cfg = SystemCommand.Config(
+      "wkhtmltopdf",
+      Seq("-s", "A4", "--encoding", "UTF-8", "-", "{{outfile}}"),
+      Duration.seconds(20)
+    )
+
+    if (!commandExists(cfg.program)) ignore(s"Command ${cfg.program} not found")
+    else {
+      File
+        .withTempDir[IO](target, "wkhtmltopdf")
+        .use(dir => IO {
+          val wkCfg = WkHtmlPdfConfig(cfg, target)
+          val p = ExampleFiles.letter_de_html
+            .readURL[IO](8192, blocker)
+            .through(WkHtmlPdf.toPDF[IO](wkCfg, 8192, blocker, logger))
+            .through(storeFile(dir.resolve("test.pdf")))
+            .compile
+            .lastOrError
+            .unsafeRunSync()
+
+          assert(Files.exists(p) && Files.size(p) > 0)
+        })
+        .unsafeRunSync
+    }
+  }
+
+  test("convert office to pdf") {
+    val cfg = SystemCommand.Config(
+      "unoconv",
+      Seq("-f", "pdf", "-o", "{{outfile}}", "{{infile}}"),
+      Duration.seconds(20)
+    )
+
+    if (!commandExists(cfg.program)) ignore(s"Command ${cfg.program} not found")
+    else {
+      File
+        .withTempDir[IO](target, "unoconv")
+        .use(dir => IO {
+          val ucCfg = UnoconvConfig(cfg, target)
+          val p = ExampleFiles.examples_sample_docx
+            .readURL[IO](8192, blocker)
+            .through(Unoconv.toPDF[IO](ucCfg, 8192, blocker, logger))
+            .through(storeFile(dir.resolve("test.pdf")))
+            .compile
+            .lastOrError
+            .unsafeRunSync()
+
+          assert(Files.exists(p) && Files.size(p) > 0)
+        })
+        .unsafeRunSync
+    }
+  }
+
+
+  def storeFile(file: Path): Pipe[IO, Byte, Path] =
+    in => Stream.eval(in.compile.to(Array).flatMap(bytes => IO(Files.write(file, bytes))))
+
+  def commandExists(cmd: String): Boolean =
+    Runtime.getRuntime().exec(Array("which", cmd)).waitFor() == 0
+}
diff --git a/modules/files/src/test/resources/letter-de.html b/modules/files/src/test/resources/letter-de.html
new file mode 100755
index 00000000..48ad7be0
--- /dev/null
+++ b/modules/files/src/test/resources/letter-de.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <meta charset="utf-8"/>
+        <style>
+         body {
+             padding: 2em 5em;
+         }
+        </style>
+    </head>
+    <body>
+        <pre>
+            <code>
+Max Mustermann
+Lilienweg 21
+12345 Nebendorf
+E-Mail: max.muster@gmail.com
+            </code>
+        </pre>
+        <p>Max Mustermann, Lilienweg 21, 12345 Nebendorf</p>
+        <p>EasyCare AG<br> Abteilung Buchhaltung<br> Ackerweg 12<br> 12346 Ulmen<br></p>
+        <p>Nebendorf, 3. September 2019</p>
+        <h2>Sehr geehrte Damen und Herren</h2>
+        <p>hiermit kündige ich meine Mitgliedschaft in der Kranken- und Pflegeversicherung zum <em>nächstmöglichen</em> Termin.</p>
+        <p>Bitte senden Sie mir innerhalb der gesetzlichen Frist von <strong>14 Tagen</strong> eine Kündigungsbestätigung zu.</p>
+        <p>Vielen Dank im Vorraus!</p>
+        <p>Mit freundlichen Grüßen</p>
+        <p>Max Mustermann</p>
+    </body>
+</html>
diff --git a/modules/joex/src/main/scala/docspell/joex/process/ConvertPdf.scala b/modules/joex/src/main/scala/docspell/joex/process/ConvertPdf.scala
index 829e36fc..23de73de 100644
--- a/modules/joex/src/main/scala/docspell/joex/process/ConvertPdf.scala
+++ b/modules/joex/src/main/scala/docspell/joex/process/ConvertPdf.scala
@@ -51,11 +51,11 @@ object ConvertPdf {
       .map(_.mimetype)
       .getOrElse(Mimetype.`application/octet-stream`)
 
-  def convertSafe[F[_]: Sync](
+  def convertSafe[F[_]: Sync: ContextShift](
       cfg: ConvertConfig,
       ctx: Context[F, ProcessItemArgs]
   )(ra: RAttachment, mime: Mimetype): F[RAttachment] =
-    Conversion.create[F](cfg).use { conv =>
+    Conversion.create[F](cfg, ctx.blocker,ctx.logger).use { conv =>
       ctx.logger
         .info(s"File ${ra.name} has mime ${mime.asString}. conv=$conv")
         .map(_ => ra)