diff --git a/registry/templates/Article.marka b/registry/templates/Article.marka
index bc1d532..a282835 100644
--- a/registry/templates/Article.marka
+++ b/registry/templates/Article.marka
@@ -29,11 +29,14 @@
       value: 5
       codec: const
       hidden: true
+    - path: keywords
     - path: reviewRating.worstRating
       value: 1
       codec: const
       hidden: true
 }
 ---
+
 # { headline }
+
 { articleBody }
diff --git a/registry/templates/Recipe.marka b/registry/templates/Recipe.marka
index feeb85e..daf66b3 100644
--- a/registry/templates/Recipe.marka
+++ b/registry/templates/Recipe.marka
@@ -34,7 +34,9 @@
     - path: suitableForDiet
 }
 ---
+
 # { name | text }
+
 { description | text }
 
 ## Ingredients
diff --git a/registry/templates/Review.marka b/registry/templates/Review.marka
index 6412db6..d34cfe2 100644
--- a/registry/templates/Review.marka
+++ b/registry/templates/Review.marka
@@ -35,5 +35,7 @@
     - path: reviewBody
 }
 ---
+
 # { itemReviewed.name }
+
 { reviewBody }
diff --git a/renderer/renderer.go b/renderer/renderer.go
index de7556c..0b3f670 100644
--- a/renderer/renderer.go
+++ b/renderer/renderer.go
@@ -37,7 +37,7 @@ func RenderFile(rawJSON []byte) ([]byte, error) {
 	}
 
 	// 5) validate JSON against schema
-	if schemaName, ok := data["@schema"].(string); ok {
+	if schemaName, ok := data["_schema"].(string); ok {
 		if validationErr := validator.ValidateSchema(data, schemaName); validationErr != nil {
 			return nil, fmt.Errorf("failed to validate schema: %w", validationErr)
 		}
diff --git a/server/internal/adapters/fs.go b/server/internal/adapters/fs.go
index 1cd48ce..18a0e9d 100644
--- a/server/internal/adapters/fs.go
+++ b/server/internal/adapters/fs.go
@@ -257,6 +257,66 @@ func (l *LocalFsAdapter) Read(path string) (*Entry, error) {
 }
 
 func (l *LocalFsAdapter) Write(path string, content []byte) error {
+	pathParts := strings.Split(strings.Trim(path, "/"), "/")
+	if len(pathParts) == 0 || pathParts[0] == "" {
+		return errors.New("invalid path")
+	}
+
+	rootIdentifier := pathParts[0]
+	var targetRoot string
+	for _, r := range l.roots {
+		if filepath.Base(r) == rootIdentifier {
+			targetRoot = r
+			break
+		}
+	}
+
+	if targetRoot == "" {
+		return ErrNotFound
+	}
+
+	subPath := filepath.Join(pathParts[1:]...)
+	target := filepath.Join(targetRoot, subPath)
+
+	absTarget, err := filepath.Abs(target)
+	if err != nil {
+		return err
+	}
+	absRoot, err := filepath.Abs(targetRoot)
+	if err != nil {
+		return err
+	}
+	if !strings.HasPrefix(absTarget, absRoot) {
+		return errors.New("path escapes root")
+	}
+
+	dir := filepath.Dir(absTarget)
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		return fmt.Errorf("failed to create directory: %w", err)
+	}
+
+	err = os.WriteFile(absTarget, content, 0o644)
+	if err != nil {
+		return err
+	}
+
+	// Invalidate cache
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	currentPath := path
+	for {
+		delete(l.cache, currentPath)
+		if currentPath == "/" {
+			break
+		}
+		lastSlash := strings.LastIndex(currentPath, "/")
+		if lastSlash <= 0 {
+			currentPath = "/"
+		} else {
+			currentPath = currentPath[:lastSlash]
+		}
+	}
+
 	return nil
 }
 
diff --git a/server/internal/handler/error.go b/server/internal/handler/error.go
index 37fcc3d..cdf875a 100644
--- a/server/internal/handler/error.go
+++ b/server/internal/handler/error.go
@@ -2,6 +2,7 @@ package handler
 
 import (
 	"encoding/json"
+	"log"
 	"net/http"
 )
 
@@ -10,6 +11,7 @@ type ErrorResponse struct {
 }
 
 func writeError(w http.ResponseWriter, code int, err error) {
+	log.Printf("error: %s", err)
 	writeJSON(w, code, ErrorResponse{Error: err.Error()})
 }
 
diff --git a/server/internal/handler/handler.go b/server/internal/handler/handler.go
index 0b063fc..7cbca84 100644
--- a/server/internal/handler/handler.go
+++ b/server/internal/handler/handler.go
@@ -3,8 +3,12 @@ package handler
 
 import (
 	"errors"
+	"fmt"
+	"io"
 	"net/http"
+	"strings"
 
+	"git.max-richter.dev/max/marka/renderer"
 	"git.max-richter.dev/max/marka/server/internal/adapters"
 )
 
@@ -44,7 +48,35 @@ func (h *Handler) get(w http.ResponseWriter, target string) {
 	writeError(w, http.StatusInternalServerError, errors.New("unknown entry type"))
 }
 
-func (h *Handler) post(w http.ResponseWriter, target string) {
+func (h *Handler) post(w http.ResponseWriter, r *http.Request, target string) {
+	body, err := io.ReadAll(r.Body)
+	if err != nil {
+		writeError(w, http.StatusBadRequest, err)
+		return
+	}
+	defer r.Body.Close()
+
+	contentType := r.Header.Get("Content-Type")
+	isJSON := strings.HasPrefix(contentType, "application/json")
+
+	var contentToWrite []byte
+	if strings.HasSuffix(target, ".md") && isJSON {
+		renderedContent, err := renderer.RenderFile(body)
+		if err != nil {
+			writeError(w, http.StatusInternalServerError, fmt.Errorf("failed to render file: %w", err))
+			return
+		}
+		contentToWrite = renderedContent
+	} else {
+		contentToWrite = body
+	}
+
+	if err := h.adapter.Write(target, contentToWrite); err != nil {
+		writeError(w, http.StatusInternalServerError, fmt.Errorf("failed to write file: %w", err))
+		return
+	}
+
+	w.WriteHeader(http.StatusNoContent)
 }
 
 func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
@@ -59,7 +91,7 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	case http.MethodGet:
 		h.get(w, target)
 	case http.MethodPost:
-		h.post(w, target)
+		h.post(w, r, target)
 	default:
 		writeError(w, http.StatusMethodNotAllowed, errors.New("method not allowed"))
 	}