diff --git a/genotype_api/constants.py b/genotype_api/constants.py
index 8b2fca7..78d1325 100644
--- a/genotype_api/constants.py
+++ b/genotype_api/constants.py
@@ -1,9 +1,13 @@
 """Constants used over the package"""
 
-from enum import Enum
+from enum import Enum, StrEnum
 from pydantic import BaseModel
 
 
+class FileExtension(StrEnum):
+    VCF: str = ".vcf"
+
+
 class Types(str, Enum):
     GENOTYPE = "genotype"
     SEQUENCE = "sequence"
diff --git a/genotype_api/services/analysis_service/analysis_service.py b/genotype_api/services/analysis_service/analysis_service.py
index a6992bd..41753ed 100644
--- a/genotype_api/services/analysis_service/analysis_service.py
+++ b/genotype_api/services/analysis_service/analysis_service.py
@@ -5,7 +5,7 @@
 from fastapi import UploadFile
 from sqlmodel import Session
 
-from genotype_api.constants import Types
+from genotype_api.constants import Types, FileExtension
 from genotype_api.database.crud.create import create_analyses_samples, create_analysis
 from genotype_api.database.crud.read import (
     get_analysis_by_id,
@@ -48,7 +48,7 @@ def get_upload_sequence_analyses(self, file: UploadFile) -> list[AnalysisRespons
         """
         Reading VCF file, creating and uploading sequence analyses and sample objects to the database.
         """
-        file_name: Path = check_file(file_path=file.filename, extension=".vcf")
+        file_name: Path = check_file(file_path=file.filename, extension=FileExtension.VCF)
         content = file.file.read().decode("utf-8")
         sequence_analysis = SequenceAnalysis(vcf_file=content, source=str(file_name))
         analyses: list[Analysis] = list(sequence_analysis.generate_analyses())