diff --git a/internal/api/api.go b/internal/api/api.go
index 2c4fa079ac..41a478074d 100644
--- a/internal/api/api.go
+++ b/internal/api/api.go
@@ -32,13 +32,14 @@ type API struct {
 	logger  logging.Logger
 	session *project.Session
 
-	projects  map[Handle[project.Project]]tspath.Path
-	filesMu   sync.Mutex
-	files     handleMap[ast.SourceFile]
-	symbolsMu sync.Mutex
-	symbols   handleMap[ast.Symbol]
-	typesMu   sync.Mutex
-	types     handleMap[checker.Type]
+	projectsMu sync.RWMutex
+	projects   map[Handle[project.Project]]tspath.Path
+	filesMu    sync.Mutex
+	files      handleMap[ast.SourceFile]
+	symbolsMu  sync.Mutex
+	symbols    handleMap[ast.Symbol]
+	typesMu    sync.Mutex
+	types      handleMap[checker.Type]
 }
 
 func NewAPI(init *APIInit) *API {
@@ -145,12 +146,18 @@ func (api *API) LoadProject(ctx context.Context, configFileName string) (*Projec
 		return nil, err
 	}
 	data := NewProjectResponse(project)
+	// Acquire write lock to safely add project to the map
+	api.projectsMu.Lock()
 	api.projects[data.Id] = project.ConfigFilePath()
+	api.projectsMu.Unlock()
 	return data, nil
 }
 
 func (api *API) GetSymbolAtPosition(ctx context.Context, projectId Handle[project.Project], fileName string, position int) (*SymbolResponse, error) {
+	// Acquire read lock to safely access projects map
+	api.projectsMu.RLock()
 	projectPath, ok := api.projects[projectId]
+	api.projectsMu.RUnlock()
 	if !ok {
 		return nil, errors.New("project ID not found")
 	}
@@ -174,7 +181,10 @@ func (api *API) GetSymbolAtPosition(ctx context.Context, projectId Handle[projec
 }
 
 func (api *API) GetSymbolAtLocation(ctx context.Context, projectId Handle[project.Project], location Handle[ast.Node]) (*SymbolResponse, error) {
+	// Acquire read lock to safely access projects map
+	api.projectsMu.RLock()
 	projectPath, ok := api.projects[projectId]
+	api.projectsMu.RUnlock()
 	if !ok {
 		return nil, errors.New("project ID not found")
 	}
@@ -216,7 +226,10 @@ func (api *API) GetSymbolAtLocation(ctx context.Context, projectId Handle[projec
 }
 
 func (api *API) GetTypeOfSymbol(ctx context.Context, projectId Handle[project.Project], symbolHandle Handle[ast.Symbol]) (*TypeResponse, error) {
+	// Acquire read lock to safely access projects map
+	api.projectsMu.RLock()
 	projectPath, ok := api.projects[projectId]
+	api.projectsMu.RUnlock()
 	if !ok {
 		return nil, errors.New("project ID not found")
 	}
@@ -242,7 +255,10 @@ func (api *API) GetTypeOfSymbol(ctx context.Context, projectId Handle[project.Pr
 }
 
 func (api *API) GetSourceFile(projectId Handle[project.Project], fileName string) (*ast.SourceFile, error) {
+	// Acquire read lock to safely access projects map
+	api.projectsMu.RLock()
 	projectPath, ok := api.projects[projectId]
+	api.projectsMu.RUnlock()
 	if !ok {
 		return nil, errors.New("project ID not found")
 	}
@@ -267,11 +283,15 @@ func (api *API) releaseHandle(handle string) error {
 	switch handle[0] {
 	case handlePrefixProject:
 		projectId := Handle[project.Project](handle)
+		// Acquire write lock to safely delete project from the map
+		api.projectsMu.Lock()
 		_, ok := api.projects[projectId]
 		if !ok {
+			api.projectsMu.Unlock()
 			return fmt.Errorf("project %q not found", handle)
 		}
 		delete(api.projects, projectId)
+		api.projectsMu.Unlock()
 	case handlePrefixFile:
 		fileId := Handle[ast.SourceFile](handle)
 		api.filesMu.Lock()