diff --git a/mapper/query.go b/mapper/query.go
new file mode 100644
index 0000000..81fddba
--- /dev/null
+++ b/mapper/query.go
@@ -0,0 +1,414 @@
+package mapper // ApplyQueryMappings applies the specified mapping rules to a JSON object
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/KorAP/KoralPipe-TermMapper/ast"
+	"github.com/KorAP/KoralPipe-TermMapper/matcher"
+	"github.com/KorAP/KoralPipe-TermMapper/parser"
+)
+
+// ApplyQueryMappings applies the specified mapping rules to a JSON object
+func (m *Mapper) ApplyQueryMappings(mappingID string, opts MappingOptions, jsonData any) (any, error) {
+	// Validate mapping ID
+	if _, exists := m.mappingLists[mappingID]; !exists {
+		return nil, fmt.Errorf("mapping list with ID %s not found", mappingID)
+	}
+
+	// Get the parsed rules
+	rules := m.parsedRules[mappingID]
+
+	// Check if we have a wrapper object with a "query" field
+	var queryData any
+	var hasQueryWrapper bool
+
+	if jsonMap, ok := jsonData.(map[string]any); ok {
+		if query, exists := jsonMap["query"]; exists {
+			queryData = query
+			hasQueryWrapper = true
+		}
+	}
+
+	// If no query wrapper was found, use the entire input
+	if !hasQueryWrapper {
+		// If the input itself is not a valid query object, return it as is
+		if !isValidQueryObject(jsonData) {
+			return jsonData, nil
+		}
+		queryData = jsonData
+	} else if queryData == nil || !isValidQueryObject(queryData) {
+		// If we have a query wrapper but the query is nil or not a valid object,
+		// return the original data
+		return jsonData, nil
+	}
+
+	// Store rewrites if they exist
+	var oldRewrites any
+	if queryMap, ok := queryData.(map[string]any); ok {
+		if rewrites, exists := queryMap["rewrites"]; exists {
+			oldRewrites = rewrites
+			delete(queryMap, "rewrites")
+		}
+	}
+
+	// Convert input JSON to AST
+	jsonBytes, err := json.Marshal(queryData)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal input JSON: %w", err)
+	}
+
+	node, err := parser.ParseJSON(jsonBytes)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse JSON into AST: %w", err)
+	}
+
+	// Store whether the input was a Token
+	isToken := false
+	var tokenWrap ast.Node
+	if token, ok := node.(*ast.Token); ok {
+		isToken = true
+		tokenWrap = token.Wrap
+		node = tokenWrap
+	}
+
+	// Store original node for rewrite if needed
+	var originalNode ast.Node
+	if opts.AddRewrites {
+		originalNode = node.Clone()
+	}
+
+	// Pre-check foundry/layer overrides to optimize processing
+	var patternFoundry, patternLayer, replacementFoundry, replacementLayer string
+	if opts.Direction { // true means AtoB
+		patternFoundry, patternLayer = opts.FoundryA, opts.LayerA
+		replacementFoundry, replacementLayer = opts.FoundryB, opts.LayerB
+	} else {
+		patternFoundry, patternLayer = opts.FoundryB, opts.LayerB
+		replacementFoundry, replacementLayer = opts.FoundryA, opts.LayerA
+	}
+
+	// Create a pattern cache key for memoization
+	type patternCacheKey struct {
+		ruleIndex     int
+		foundry       string
+		layer         string
+		isReplacement bool
+	}
+	patternCache := make(map[patternCacheKey]ast.Node)
+
+	// Apply each rule to the AST
+	for i, rule := range rules {
+		// Create pattern and replacement based on direction
+		var pattern, replacement ast.Node
+		if opts.Direction { // true means AtoB
+			pattern = rule.Upper
+			replacement = rule.Lower
+		} else {
+			pattern = rule.Lower
+			replacement = rule.Upper
+		}
+
+		// Extract the inner nodes from the pattern and replacement tokens
+		if token, ok := pattern.(*ast.Token); ok {
+			pattern = token.Wrap
+		}
+		if token, ok := replacement.(*ast.Token); ok {
+			replacement = token.Wrap
+		}
+
+		// First, quickly check if the pattern could match without creating a full matcher
+		// This is a lightweight pre-check to avoid expensive operations
+		if !m.couldPatternMatch(node, pattern) {
+			continue
+		}
+
+		// Get or create pattern with overrides
+		patternKey := patternCacheKey{ruleIndex: i, foundry: patternFoundry, layer: patternLayer, isReplacement: false}
+		processedPattern, exists := patternCache[patternKey]
+		if !exists {
+			// Clone pattern only when needed
+			processedPattern = pattern.Clone()
+			// Apply foundry and layer overrides only if they're non-empty
+			if patternFoundry != "" || patternLayer != "" {
+				ast.ApplyFoundryAndLayerOverrides(processedPattern, patternFoundry, patternLayer)
+			}
+			patternCache[patternKey] = processedPattern
+		}
+
+		// Create a temporary matcher to check for actual matches
+		tempMatcher, err := matcher.NewMatcher(ast.Pattern{Root: processedPattern}, ast.Replacement{Root: &ast.Term{}})
+		if err != nil {
+			return nil, fmt.Errorf("failed to create temporary matcher: %w", err)
+		}
+
+		// Only proceed if there's an actual match
+		if !tempMatcher.Match(node) {
+			continue
+		}
+
+		// Get or create replacement with overrides (lazy evaluation)
+		replacementKey := patternCacheKey{ruleIndex: i, foundry: replacementFoundry, layer: replacementLayer, isReplacement: true}
+		processedReplacement, exists := patternCache[replacementKey]
+		if !exists {
+			// Clone replacement only when we have a match
+			processedReplacement = replacement.Clone()
+			// Apply foundry and layer overrides only if they're non-empty
+			if replacementFoundry != "" || replacementLayer != "" {
+				ast.ApplyFoundryAndLayerOverrides(processedReplacement, replacementFoundry, replacementLayer)
+			}
+			patternCache[replacementKey] = processedReplacement
+		}
+
+		// Create the actual matcher and apply replacement
+		actualMatcher, err := matcher.NewMatcher(ast.Pattern{Root: processedPattern}, ast.Replacement{Root: processedReplacement})
+		if err != nil {
+			return nil, fmt.Errorf("failed to create matcher: %w", err)
+		}
+		node = actualMatcher.Replace(node)
+	}
+
+	// Wrap the result in a token if the input was a token
+	var result ast.Node
+	if isToken {
+		result = &ast.Token{Wrap: node}
+	} else {
+		result = node
+	}
+
+	// Convert AST back to JSON
+	resultBytes, err := parser.SerializeToJSON(result)
+	if err != nil {
+		return nil, fmt.Errorf("failed to serialize AST to JSON: %w", err)
+	}
+
+	// Parse the JSON string back into
+	var resultData any
+	if err := json.Unmarshal(resultBytes, &resultData); err != nil {
+		return nil, fmt.Errorf("failed to parse result JSON: %w", err)
+	}
+
+	// Add rewrites if enabled and node was changed
+	if opts.AddRewrites && !ast.NodesEqual(node, originalNode) {
+		// Create rewrite object
+		rewrite := map[string]any{
+			"@type":  "koral:rewrite",
+			"editor": "termMapper",
+		}
+
+		// Check if the node types are different (structural change)
+		if originalNode.Type() != node.Type() {
+			// Full node replacement
+			originalBytes, err := parser.SerializeToJSON(originalNode)
+			if err != nil {
+				return nil, fmt.Errorf("failed to serialize original node for rewrite: %w", err)
+			}
+			var originalJSON any
+			if err := json.Unmarshal(originalBytes, &originalJSON); err != nil {
+				return nil, fmt.Errorf("failed to parse original node JSON for rewrite: %w", err)
+			}
+			rewrite["original"] = originalJSON
+		} else if term, ok := originalNode.(*ast.Term); ok && ast.IsTermNode(node) {
+			// Check which attributes changed
+			newTerm := node.(*ast.Term)
+			if term.Foundry != newTerm.Foundry {
+				rewrite["scope"] = "foundry"
+				rewrite["original"] = term.Foundry
+			} else if term.Layer != newTerm.Layer {
+				rewrite["scope"] = "layer"
+				rewrite["original"] = term.Layer
+			} else if term.Key != newTerm.Key {
+				rewrite["scope"] = "key"
+				rewrite["original"] = term.Key
+			} else if term.Value != newTerm.Value {
+				rewrite["scope"] = "value"
+				rewrite["original"] = term.Value
+			} else {
+				// No specific attribute changed, use full node replacement
+				originalBytes, err := parser.SerializeToJSON(originalNode)
+				if err != nil {
+					return nil, fmt.Errorf("failed to serialize original node for rewrite: %w", err)
+				}
+				var originalJSON any
+				if err := json.Unmarshal(originalBytes, &originalJSON); err != nil {
+					return nil, fmt.Errorf("failed to parse original node JSON for rewrite: %w", err)
+				}
+				rewrite["original"] = originalJSON
+			}
+		} else {
+			// Full node replacement
+			originalBytes, err := parser.SerializeToJSON(originalNode)
+			if err != nil {
+				return nil, fmt.Errorf("failed to serialize original node for rewrite: %w", err)
+			}
+			var originalJSON any
+			if err := json.Unmarshal(originalBytes, &originalJSON); err != nil {
+				return nil, fmt.Errorf("failed to parse original node JSON for rewrite: %w", err)
+			}
+			rewrite["original"] = originalJSON
+		}
+
+		// Add rewrite to the node
+		if resultMap, ok := resultData.(map[string]any); ok {
+			if wrapMap, ok := resultMap["wrap"].(map[string]any); ok {
+				rewrites, exists := wrapMap["rewrites"]
+				if !exists {
+					rewrites = []any{}
+				}
+				if rewritesList, ok := rewrites.([]any); ok {
+					wrapMap["rewrites"] = append(rewritesList, rewrite)
+				} else {
+					wrapMap["rewrites"] = []any{rewrite}
+				}
+			}
+		}
+	}
+
+	// Restore rewrites if they existed
+	if oldRewrites != nil {
+		// Process old rewrites through AST to ensure backward compatibility
+		if rewritesList, ok := oldRewrites.([]any); ok {
+			processedRewrites := make([]any, len(rewritesList))
+			for i, rewriteData := range rewritesList {
+				// Marshal and unmarshal each rewrite to apply backward compatibility
+				rewriteBytes, err := json.Marshal(rewriteData)
+				if err != nil {
+					return nil, fmt.Errorf("failed to marshal old rewrite %d: %w", i, err)
+				}
+				var rewrite ast.Rewrite
+				if err := json.Unmarshal(rewriteBytes, &rewrite); err != nil {
+					return nil, fmt.Errorf("failed to unmarshal old rewrite %d: %w", i, err)
+				}
+				// Marshal back to get the transformed version
+				transformedBytes, err := json.Marshal(&rewrite)
+				if err != nil {
+					return nil, fmt.Errorf("failed to marshal transformed rewrite %d: %w", i, err)
+				}
+				var transformedRewrite any
+				if err := json.Unmarshal(transformedBytes, &transformedRewrite); err != nil {
+					return nil, fmt.Errorf("failed to unmarshal transformed rewrite %d: %w", i, err)
+				}
+				processedRewrites[i] = transformedRewrite
+			}
+			if resultMap, ok := resultData.(map[string]any); ok {
+				resultMap["rewrites"] = processedRewrites
+			}
+		} else {
+			// If it's not a list, restore as-is
+			if resultMap, ok := resultData.(map[string]any); ok {
+				resultMap["rewrites"] = oldRewrites
+			}
+		}
+	}
+
+	// If we had a query wrapper, put the transformed data back in it
+	if hasQueryWrapper {
+		if wrapper, ok := jsonData.(map[string]any); ok {
+			wrapper["query"] = resultData
+			return wrapper, nil
+		}
+	}
+
+	return resultData, nil
+}
+
+// isValidQueryObject checks if the query data is a valid object that can be processed
+func isValidQueryObject(data any) bool {
+	// Check if it's a map
+	queryMap, ok := data.(map[string]any)
+	if !ok {
+		return false
+	}
+
+	// Check if it has the required @type field
+	if _, ok := queryMap["@type"]; !ok {
+		return false
+	}
+
+	return true
+}
+
+// couldPatternMatch performs a lightweight check to see if a pattern could potentially match a node
+// This is an optimization to avoid expensive operations when there's clearly no match possible
+func (m *Mapper) couldPatternMatch(node, pattern ast.Node) bool {
+	if pattern == nil {
+		return true
+	}
+	if node == nil {
+		return false
+	}
+
+	// Handle Token wrappers
+	if token, ok := pattern.(*ast.Token); ok {
+		pattern = token.Wrap
+	}
+	if token, ok := node.(*ast.Token); ok {
+		node = token.Wrap
+	}
+
+	// For simple terms, check basic compatibility
+	if patternTerm, ok := pattern.(*ast.Term); ok {
+		// Check if there's any term in the node structure that could match
+		return m.hasMatchingTerm(node, patternTerm)
+	}
+
+	// For TermGroups, we need to check all possible matches
+	if patternGroup, ok := pattern.(*ast.TermGroup); ok {
+		if patternGroup.Relation == ast.OrRelation {
+			// For OR relations, any operand could match
+			for _, op := range patternGroup.Operands {
+				if m.couldPatternMatch(node, op) {
+					return true
+				}
+			}
+			return false
+		} else {
+			// For AND relations, all operands must have potential matches
+			for _, op := range patternGroup.Operands {
+				if !m.couldPatternMatch(node, op) {
+					return false
+				}
+			}
+			return true
+		}
+	}
+
+	// For other cases, assume they could match (conservative approach)
+	return true
+}
+
+// hasMatchingTerm checks if there's any term in the node structure that could match the pattern term
+func (m *Mapper) hasMatchingTerm(node ast.Node, patternTerm *ast.Term) bool {
+	if node == nil {
+		return false
+	}
+
+	switch n := node.(type) {
+	case *ast.Term:
+		// Check if this term could match the pattern
+		// We only check key as that's the most distinctive attribute
+		return n.Key == patternTerm.Key
+	case *ast.TermGroup:
+		// Check all operands
+		for _, op := range n.Operands {
+			if m.hasMatchingTerm(op, patternTerm) {
+				return true
+			}
+		}
+		return false
+	case *ast.Token:
+		return m.hasMatchingTerm(n.Wrap, patternTerm)
+	case *ast.CatchallNode:
+		if n.Wrap != nil && m.hasMatchingTerm(n.Wrap, patternTerm) {
+			return true
+		}
+		for _, op := range n.Operands {
+			if m.hasMatchingTerm(op, patternTerm) {
+				return true
+			}
+		}
+		return false
+	default:
+		return false
+	}
+}