diff --git a/pdftract-go/pdftract.go b/pdftract-go/pdftract.go
index 8ad0905..b5fd005 100644
--- a/pdftract-go/pdftract.go
+++ b/pdftract-go/pdftract.go
@@ -54,7 +54,7 @@ func (c *Client) Extract(ctx context.Context, source Source, opts *ExtractOption
 	}
 
 	var doc Document
-	if err := c.invokeJSON(ctx, args, &doc); err != nil {
+	if err := c.invokeJSON(ctx, args, &doc, source); err != nil {
 		return nil, err
 	}
 
@@ -70,7 +70,7 @@ func (c *Client) ExtractText(ctx context.Context, source Source, opts *ExtractOp
 		args = append(args, opts.toArgs()...)
 	}
 
-	return c.invokeString(ctx, args)
+	return c.invokeString(ctx, args, source)
 }
 
 // ExtractMarkdown extracts markdown-formatted text from a PDF.
@@ -82,7 +82,7 @@ func (c *Client) ExtractMarkdown(ctx context.Context, source Source, opts *Extra
 		args = append(args, opts.toArgs()...)
 	}
 
-	return c.invokeString(ctx, args)
+	return c.invokeString(ctx, args, source)
 }
 
 // ExtractStream extracts pages from a PDF as a stream.
@@ -107,7 +107,7 @@ func (c *Client) GetMetadata(ctx context.Context, source Source, opts *ExtractOp
 	var result struct {
 		Metadata Metadata `json:"metadata"`
 	}
-	if err := c.invokeJSON(ctx, args, &result); err != nil {
+	if err := c.invokeJSON(ctx, args, &result, source); err != nil {
 		return nil, err
 	}
 
@@ -124,7 +124,7 @@ func (c *Client) Hash(ctx context.Context, source Source, opts *HashOptions) (*F
 	}
 
 	var fp Fingerprint
-	if err := c.invokeJSON(ctx, args, &fp); err != nil {
+	if err := c.invokeJSON(ctx, args, &fp, source); err != nil {
 		return nil, err
 	}
 
@@ -137,7 +137,7 @@ func (c *Client) Classify(ctx context.Context, source Source) (*Classification,
 	args = append(args, source.source()...)
 
 	var cls Classification
-	if err := c.invokeJSON(ctx, args, &cls); err != nil {
+	if err := c.invokeJSON(ctx, args, &cls, source); err != nil {
 		return nil, err
 	}
 
diff --git a/pdftract-go/source.go b/pdftract-go/source.go
index e0da7c3..0d74b55 100644
--- a/pdftract-go/source.go
+++ b/pdftract-go/source.go
@@ -34,10 +34,43 @@ func (u URLSource) source() []string {
 }
 
 // BytesSource represents in-memory PDF bytes.
-type BytesSource []byte
+// The temporary file created for subprocess consumption is cleaned up after use.
+type BytesSource struct {
+	data    []byte
+	tmpPath string
+}
 
-func (b BytesSource) source() []string {
-	return []string{"--bytes-data", string(b)}
+// MemorySource is a convenience constructor that creates a BytesSource from a byte slice.
+func MemorySource(data []byte) Source {
+	return &BytesSource{data: data}
+}
+
+func (b *BytesSource) source() []string {
+	if b.tmpPath != "" {
+		return []string{b.tmpPath}
+	}
+
+	// Write to a temporary file for subprocess consumption
+	tmpFile, err := os.CreateTemp("", "pdftract-*.pdf")
+	if err != nil {
+		panic(fmt.Sprintf("failed to create temp file for BytesSource: %v", err))
+	}
+	defer tmpFile.Close()
+
+	if _, err := tmpFile.Write(b.data); err != nil {
+		panic(fmt.Sprintf("failed to write data to temp file: %v", err))
+	}
+
+	b.tmpPath = tmpFile.Name()
+	return []string{b.tmpPath}
+}
+
+// cleanup removes the temporary file if it was created.
+func (b *BytesSource) cleanup() {
+	if b.tmpPath != "" && !strings.HasPrefix(b.tmpPath, "--error:") {
+		os.Remove(b.tmpPath)
+		b.tmpPath = ""
+	}
 }
 
 // FileSource is a convenience constructor that creates a PathSource from a string.
@@ -53,10 +86,6 @@ func RemoteSource(url string) Source {
 	return URLSource(url)
 }
 
-// MemorySource is a convenience constructor that creates a BytesSource from a byte slice.
-func MemorySource(data []byte) Source {
-	return BytesSource(data)
-}
 
 // ReadFileSource reads a file and returns a BytesSource.
 func ReadFileSource(path string) (Source, error) {
@@ -64,5 +93,5 @@ func ReadFileSource(path string) (Source, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to read file: %w", err)
 	}
-	return BytesSource(data), nil
+	return &BytesSource{data: data}, nil
 }
diff --git a/pdftract-go/subprocess.go b/pdftract-go/subprocess.go
index 8105cb7..660dbbd 100644
--- a/pdftract-go/subprocess.go
+++ b/pdftract-go/subprocess.go
@@ -18,7 +18,7 @@ type subprocessResult struct {
 
 // invoke executes the pdftract binary with the given arguments and context.
 // It returns the combined stdout/stderr output and any error that occurred.
-func (c *Client) invoke(ctx context.Context, args []string) ([]byte, error) {
+func (c *Client) invoke(ctx context.Context, args []string, source Source) ([]byte, error) {
 	cmd := exec.CommandContext(ctx, c.binaryPath, args...)
 
 	// Set up cancellation to kill the process
@@ -34,6 +34,11 @@ func (c *Client) invoke(ctx context.Context, args []string) ([]byte, error) {
 		}
 	}
 
+	// Ensure cleanup of BytesSource temp files
+	if bs, ok := source.(*BytesSource); ok {
+		defer bs.cleanup()
+	}
+
 	output, err := cmd.CombinedOutput()
 	if err != nil {
 		if ctx.Err() != nil {
@@ -54,8 +59,8 @@ func (c *Client) invoke(ctx context.Context, args []string) ([]byte, error) {
 }
 
 // invokeJSON executes the pdftract binary and parses the output as JSON.
-func (c *Client) invokeJSON(ctx context.Context, args []string, result interface{}) error {
-	output, err := c.invoke(ctx, args)
+func (c *Client) invokeJSON(ctx context.Context, args []string, result interface{}, source Source) error {
+	output, err := c.invoke(ctx, args, source)
 	if err != nil {
 		return err
 	}
@@ -72,8 +77,8 @@ func (c *Client) invokeJSON(ctx context.Context, args []string, result interface
 }
 
 // invokeString executes the pdftract binary and returns the output as a string.
-func (c *Client) invokeString(ctx context.Context, args []string) (string, error) {
-	output, err := c.invoke(ctx, args)
+func (c *Client) invokeString(ctx context.Context, args []string, source Source) (string, error) {
+	output, err := c.invoke(ctx, args, source)
 	if err != nil {
 		return "", err
 	}
@@ -81,7 +86,7 @@ func (c *Client) invokeString(ctx context.Context, args []string) (string, error
 }
 
 // invokeStream executes the pdftract binary and streams JSONL output to a channel.
-func (c *Client) invokeStream(ctx context.Context, args []string) (<-chan json.RawMessage, <-chan error) {
+func (c *Client) invokeStream(ctx context.Context, args []string, source Source) (<-chan json.RawMessage, <-chan error) {
 	resultChan := make(chan json.RawMessage, 16)
 	errChan := make(chan error, 1)
 
@@ -89,6 +94,11 @@ func (c *Client) invokeStream(ctx context.Context, args []string) (<-chan json.R
 		defer close(resultChan)
 		defer close(errChan)
 
+		// Ensure cleanup of BytesSource temp files
+		if bs, ok := source.(*BytesSource); ok {
+			defer bs.cleanup()
+		}
+
 		cmd := exec.CommandContext(ctx, c.binaryPath, args...)
 
 		// Set up cancellation to kill the process