diff --git a/pkg/common/adapters/router/bunrouter.go b/pkg/common/adapters/router/bunrouter.go
index c4c1ab6..d2d642c 100644
--- a/pkg/common/adapters/router/bunrouter.go
+++ b/pkg/common/adapters/router/bunrouter.go
@@ -121,6 +121,16 @@ func (b *BunRouterRequest) QueryParam(key string) string {
 	return b.req.URL.Query().Get(key)
 }
 
+func (b *BunRouterRequest) AllQueryParams() map[string]string {
+	params := make(map[string]string)
+	for key, values := range b.req.URL.Query() {
+		if len(values) > 0 {
+			params[key] = values[0]
+		}
+	}
+	return params
+}
+
 func (b *BunRouterRequest) AllHeaders() map[string]string {
 	headers := make(map[string]string)
 	for key, values := range b.req.Header {
diff --git a/pkg/common/adapters/router/mux.go b/pkg/common/adapters/router/mux.go
index 40b0a59..96f0b97 100644
--- a/pkg/common/adapters/router/mux.go
+++ b/pkg/common/adapters/router/mux.go
@@ -117,6 +117,16 @@ func (h *HTTPRequest) QueryParam(key string) string {
 	return h.req.URL.Query().Get(key)
 }
 
+func (h *HTTPRequest) AllQueryParams() map[string]string {
+	params := make(map[string]string)
+	for key, values := range h.req.URL.Query() {
+		if len(values) > 0 {
+			params[key] = values[0]
+		}
+	}
+	return params
+}
+
 func (h *HTTPRequest) AllHeaders() map[string]string {
 	headers := make(map[string]string)
 	for key, values := range h.req.Header {
diff --git a/pkg/common/interfaces.go b/pkg/common/interfaces.go
index 5d85dee..103c47b 100644
--- a/pkg/common/interfaces.go
+++ b/pkg/common/interfaces.go
@@ -116,6 +116,7 @@ type Request interface {
 	Body() ([]byte, error)
 	PathParam(key string) string
 	QueryParam(key string) string
+	AllQueryParams() map[string]string // Get all query parameters as a map
 }
 
 // ResponseWriter interface abstracts HTTP response
diff --git a/pkg/restheadspec/headers.go b/pkg/restheadspec/headers.go
index 7438673..cd9580b 100644
--- a/pkg/restheadspec/headers.go
+++ b/pkg/restheadspec/headers.go
@@ -117,15 +117,28 @@ func (h *Handler) parseOptionsFromHeaders(r common.Request, model interface{}) E
 	// Get all headers
 	headers := r.AllHeaders()
 
-	// Process each header
+	// Get all query parameters
+	queryParams := r.AllQueryParams()
+
+	// Merge headers and query parameters - query parameters take precedence
+	// This allows the same parameters to be specified in either headers or query string
+	combinedParams := make(map[string]string)
 	for key, value := range headers {
-		// Normalize header key to lowercase for consistent matching
+		combinedParams[key] = value
+	}
+	for key, value := range queryParams {
+		combinedParams[key] = value
+	}
+
+	// Process each parameter (from both headers and query params)
+	for key, value := range combinedParams {
+		// Normalize parameter key to lowercase for consistent matching
 		normalizedKey := strings.ToLower(key)
 
 		// Decode value if it's base64 encoded
 		decodedValue := decodeHeaderValue(value)
 
-		// Parse based on header prefix/name
+		// Parse based on parameter prefix/name
 		switch {
 		// Field Selection
 		case strings.HasPrefix(normalizedKey, "x-select-fields"):
@@ -158,7 +171,7 @@ func (h *Handler) parseOptionsFromHeaders(r common.Request, model interface{}) E
 			if strings.HasSuffix(normalizedKey, "-where") {
 				continue
 			}
-			whereClaude := headers[fmt.Sprintf("%s-where", key)]
+			whereClaude := combinedParams[fmt.Sprintf("%s-where", key)]
 			h.parsePreload(&options, decodedValue, decodeHeaderValue(whereClaude))
 
 		case strings.HasPrefix(normalizedKey, "x-expand"):
diff --git a/pkg/restheadspec/query_params_test.go b/pkg/restheadspec/query_params_test.go
new file mode 100644
index 0000000..0633c25
--- /dev/null
+++ b/pkg/restheadspec/query_params_test.go
@@ -0,0 +1,403 @@
+package restheadspec
+
+import (
+	"testing"
+)
+
+// MockRequest implements common.Request interface for testing
+type MockRequest struct {
+	headers     map[string]string
+	queryParams map[string]string
+}
+
+func (m *MockRequest) Method() string {
+	return "GET"
+}
+
+func (m *MockRequest) URL() string {
+	return "http://example.com/test"
+}
+
+func (m *MockRequest) Header(key string) string {
+	return m.headers[key]
+}
+
+func (m *MockRequest) AllHeaders() map[string]string {
+	return m.headers
+}
+
+func (m *MockRequest) Body() ([]byte, error) {
+	return nil, nil
+}
+
+func (m *MockRequest) PathParam(key string) string {
+	return ""
+}
+
+func (m *MockRequest) QueryParam(key string) string {
+	return m.queryParams[key]
+}
+
+func (m *MockRequest) AllQueryParams() map[string]string {
+	return m.queryParams
+}
+
+func TestParseOptionsFromQueryParams(t *testing.T) {
+	handler := NewHandler(nil, nil)
+
+	tests := []struct {
+		name        string
+		queryParams map[string]string
+		headers     map[string]string
+		validate    func(t *testing.T, options ExtendedRequestOptions)
+	}{
+		{
+			name: "Parse custom SQL WHERE from query params",
+			queryParams: map[string]string{
+				"x-custom-sql-w-1": `("v_webui_clients".clientstatus = 0 or "v_webui_clients".clientstatus is null)`,
+			},
+			validate: func(t *testing.T, options ExtendedRequestOptions) {
+				if options.CustomSQLWhere == "" {
+					t.Error("Expected CustomSQLWhere to be set from query param")
+				}
+				expected := `("v_webui_clients".clientstatus = 0 or "v_webui_clients".clientstatus is null)`
+				if options.CustomSQLWhere != expected {
+					t.Errorf("Expected CustomSQLWhere=%q, got %q", expected, options.CustomSQLWhere)
+				}
+			},
+		},
+		{
+			name: "Parse sort from query params",
+			queryParams: map[string]string{
+				"x-sort": "-applicationdate,name",
+			},
+			validate: func(t *testing.T, options ExtendedRequestOptions) {
+				if len(options.Sort) != 2 {
+					t.Errorf("Expected 2 sort options, got %d", len(options.Sort))
+					return
+				}
+				if options.Sort[0].Column != "applicationdate" || options.Sort[0].Direction != "DESC" {
+					t.Errorf("Expected first sort: applicationdate DESC, got %s %s", options.Sort[0].Column, options.Sort[0].Direction)
+				}
+				if options.Sort[1].Column != "name" || options.Sort[1].Direction != "ASC" {
+					t.Errorf("Expected second sort: name ASC, got %s %s", options.Sort[1].Column, options.Sort[1].Direction)
+				}
+			},
+		},
+		{
+			name: "Parse limit and offset from query params",
+			queryParams: map[string]string{
+				"x-limit":  "100",
+				"x-offset": "50",
+			},
+			validate: func(t *testing.T, options ExtendedRequestOptions) {
+				if options.Limit == nil || *options.Limit != 100 {
+					t.Errorf("Expected limit=100, got %v", options.Limit)
+				}
+				if options.Offset == nil || *options.Offset != 50 {
+					t.Errorf("Expected offset=50, got %v", options.Offset)
+				}
+			},
+		},
+		{
+			name: "Parse field filters from query params",
+			queryParams: map[string]string{
+				"x-fieldfilter-status": "active",
+				"x-fieldfilter-type":   "user",
+			},
+			validate: func(t *testing.T, options ExtendedRequestOptions) {
+				if len(options.Filters) != 2 {
+					t.Errorf("Expected 2 filters, got %d", len(options.Filters))
+					return
+				}
+				// Check that filters were created
+				foundStatus := false
+				foundType := false
+				for _, filter := range options.Filters {
+					if filter.Column == "status" && filter.Value == "active" && filter.Operator == "eq" {
+						foundStatus = true
+					}
+					if filter.Column == "type" && filter.Value == "user" && filter.Operator == "eq" {
+						foundType = true
+					}
+				}
+				if !foundStatus {
+					t.Error("Expected status filter not found")
+				}
+				if !foundType {
+					t.Error("Expected type filter not found")
+				}
+			},
+		},
+		{
+			name: "Parse select fields from query params",
+			queryParams: map[string]string{
+				"x-select-fields": "id,name,email",
+			},
+			validate: func(t *testing.T, options ExtendedRequestOptions) {
+				if len(options.Columns) != 3 {
+					t.Errorf("Expected 3 columns, got %d", len(options.Columns))
+					return
+				}
+				expected := []string{"id", "name", "email"}
+				for i, col := range expected {
+					if i >= len(options.Columns) || options.Columns[i] != col {
+						t.Errorf("Expected column[%d]=%s, got %v", i, col, options.Columns)
+					}
+				}
+			},
+		},
+		{
+			name: "Parse preload from query params",
+			queryParams: map[string]string{
+				"x-preload": "posts:title,content|comments",
+			},
+			validate: func(t *testing.T, options ExtendedRequestOptions) {
+				if len(options.Preload) != 2 {
+					t.Errorf("Expected 2 preload options, got %d", len(options.Preload))
+					return
+				}
+				// Check first preload (posts with columns)
+				if options.Preload[0].Relation != "posts" {
+					t.Errorf("Expected first preload relation=posts, got %s", options.Preload[0].Relation)
+				}
+				if len(options.Preload[0].Columns) != 2 {
+					t.Errorf("Expected 2 columns for posts preload, got %d", len(options.Preload[0].Columns))
+				}
+				// Check second preload (comments without columns)
+				if options.Preload[1].Relation != "comments" {
+					t.Errorf("Expected second preload relation=comments, got %s", options.Preload[1].Relation)
+				}
+			},
+		},
+		{
+			name: "Query params take precedence over headers",
+			queryParams: map[string]string{
+				"x-limit": "100",
+			},
+			headers: map[string]string{
+				"X-Limit": "50",
+			},
+			validate: func(t *testing.T, options ExtendedRequestOptions) {
+				if options.Limit == nil || *options.Limit != 100 {
+					t.Errorf("Expected query param limit=100 to override header, got %v", options.Limit)
+				}
+			},
+		},
+		{
+			name: "Parse search operators from query params",
+			queryParams: map[string]string{
+				"x-searchop-contains-name": "john",
+				"x-searchop-gt-age":        "18",
+			},
+			validate: func(t *testing.T, options ExtendedRequestOptions) {
+				if len(options.Filters) != 2 {
+					t.Errorf("Expected 2 filters, got %d", len(options.Filters))
+					return
+				}
+				// Check for ILIKE filter
+				foundContains := false
+				foundGt := false
+				for _, filter := range options.Filters {
+					if filter.Column == "name" && filter.Operator == "ilike" {
+						foundContains = true
+					}
+					if filter.Column == "age" && filter.Operator == "gt" && filter.Value == "18" {
+						foundGt = true
+					}
+				}
+				if !foundContains {
+					t.Error("Expected contains filter not found")
+				}
+				if !foundGt {
+					t.Error("Expected gt filter not found")
+				}
+			},
+		},
+		{
+			name: "Parse complex example with multiple params",
+			queryParams: map[string]string{
+				"x-custom-sql-w-1":     `("v_webui_clients".clientstatus = 0)`,
+				"x-sort":               "-applicationdate",
+				"x-limit":              "100",
+				"x-select-fields":      "id,name,status",
+				"x-fieldfilter-active": "true",
+			},
+			validate: func(t *testing.T, options ExtendedRequestOptions) {
+				// Validate CustomSQLWhere
+				if options.CustomSQLWhere == "" {
+					t.Error("Expected CustomSQLWhere to be set")
+				}
+				// Validate Sort
+				if len(options.Sort) != 1 || options.Sort[0].Column != "applicationdate" || options.Sort[0].Direction != "DESC" {
+					t.Errorf("Expected sort by applicationdate DESC, got %v", options.Sort)
+				}
+				// Validate Limit
+				if options.Limit == nil || *options.Limit != 100 {
+					t.Errorf("Expected limit=100, got %v", options.Limit)
+				}
+				// Validate Columns
+				if len(options.Columns) != 3 {
+					t.Errorf("Expected 3 columns, got %d", len(options.Columns))
+				}
+				// Validate Filters
+				if len(options.Filters) < 1 {
+					t.Error("Expected at least 1 filter")
+				}
+			},
+		},
+		{
+			name: "Parse distinct flag from query params",
+			queryParams: map[string]string{
+				"x-distinct": "true",
+			},
+			validate: func(t *testing.T, options ExtendedRequestOptions) {
+				if !options.Distinct {
+					t.Error("Expected Distinct to be true")
+				}
+			},
+		},
+		{
+			name: "Parse skip count flag from query params",
+			queryParams: map[string]string{
+				"x-skipcount": "true",
+			},
+			validate: func(t *testing.T, options ExtendedRequestOptions) {
+				if !options.SkipCount {
+					t.Error("Expected SkipCount to be true")
+				}
+			},
+		},
+		{
+			name: "Parse response format from query params",
+			queryParams: map[string]string{
+				"x-syncfusion": "true",
+			},
+			validate: func(t *testing.T, options ExtendedRequestOptions) {
+				if options.ResponseFormat != "syncfusion" {
+					t.Errorf("Expected ResponseFormat=syncfusion, got %s", options.ResponseFormat)
+				}
+			},
+		},
+		{
+			name: "Parse custom SQL OR from query params",
+			queryParams: map[string]string{
+				"x-custom-sql-or": `("field1" = 'value1' OR "field2" = 'value2')`,
+			},
+			validate: func(t *testing.T, options ExtendedRequestOptions) {
+				if options.CustomSQLOr == "" {
+					t.Error("Expected CustomSQLOr to be set")
+				}
+				expected := `("field1" = 'value1' OR "field2" = 'value2')`
+				if options.CustomSQLOr != expected {
+					t.Errorf("Expected CustomSQLOr=%q, got %q", expected, options.CustomSQLOr)
+				}
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Create mock request
+			req := &MockRequest{
+				headers:     tt.headers,
+				queryParams: tt.queryParams,
+			}
+			if req.headers == nil {
+				req.headers = make(map[string]string)
+			}
+			if req.queryParams == nil {
+				req.queryParams = make(map[string]string)
+			}
+
+			// Parse options
+			options := handler.parseOptionsFromHeaders(req, nil)
+
+			// Validate
+			tt.validate(t, options)
+		})
+	}
+}
+
+func TestQueryParamsWithURLEncoding(t *testing.T) {
+	handler := NewHandler(nil, nil)
+
+	// Test with URL-encoded query parameter (like the user's example)
+	req := &MockRequest{
+		headers: make(map[string]string),
+		queryParams: map[string]string{
+			// URL-encoded version of the SQL WHERE clause
+			"x-custom-sql-w-1": `("v_webui_clients".clientstatus = 0 or "v_webui_clients".clientstatus is null) and ("v_webui_clients".inactive = 0 or "v_webui_clients".inactive is null)`,
+		},
+	}
+
+	options := handler.parseOptionsFromHeaders(req, nil)
+
+	if options.CustomSQLWhere == "" {
+		t.Error("Expected CustomSQLWhere to be set from URL-encoded query param")
+	}
+
+	// The SQL should contain the expected conditions
+	if !contains(options.CustomSQLWhere, "clientstatus") {
+		t.Error("Expected CustomSQLWhere to contain 'clientstatus'")
+	}
+	if !contains(options.CustomSQLWhere, "inactive") {
+		t.Error("Expected CustomSQLWhere to contain 'inactive'")
+	}
+}
+
+func TestHeadersAndQueryParamsCombined(t *testing.T) {
+	handler := NewHandler(nil, nil)
+
+	// Test that headers and query params can work together
+	req := &MockRequest{
+		headers: map[string]string{
+			"X-Select-Fields": "id,name",
+			"X-Limit":         "50",
+		},
+		queryParams: map[string]string{
+			"x-sort":   "-created_at",
+			"x-offset": "10",
+			// This should override the header value
+			"x-limit": "100",
+		},
+	}
+
+	options := handler.parseOptionsFromHeaders(req, nil)
+
+	// Verify columns from header
+	if len(options.Columns) != 2 {
+		t.Errorf("Expected 2 columns from header, got %d", len(options.Columns))
+	}
+
+	// Verify sort from query param
+	if len(options.Sort) != 1 || options.Sort[0].Column != "created_at" {
+		t.Errorf("Expected sort from query param, got %v", options.Sort)
+	}
+
+	// Verify offset from query param
+	if options.Offset == nil || *options.Offset != 10 {
+		t.Errorf("Expected offset=10 from query param, got %v", options.Offset)
+	}
+
+	// Verify limit from query param (should override header)
+	if options.Limit == nil {
+		t.Error("Expected limit to be set from query param")
+	} else if *options.Limit != 100 {
+		t.Errorf("Expected limit=100 from query param (overriding header), got %d", *options.Limit)
+	}
+}
+
+// Helper function to check if a string contains a substring
+func contains(s, substr string) bool {
+	return len(s) >= len(substr) && (s == substr || len(s) > len(substr) && containsHelper(s, substr))
+}
+
+func containsHelper(s, substr string) bool {
+	for i := 0; i <= len(s)-len(substr); i++ {
+		if s[i:i+len(substr)] == substr {
+			return true
+		}
+	}
+	return false
+}