diff --git a/src/config.ts b/src/config.ts
index 5f54ce3..5dd7d19 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -3,5 +3,6 @@ dotenvSafe.config();
 export const config = {
     internal_port: process.env.APP_PORT || 4010,
     development: process.env.NODE_ENV === "production",
-    jwt_secret: process.env.JWT_SECRET || "secretjwtsecret"
+    jwt_secret: process.env.JWT_SECRET || "secretjwtsecret",
+    phone_validation_countrycode: process.env.PHONE_COUNTRYCODE || "ZZ"
 }
\ No newline at end of file
diff --git a/src/models/creation/CreateGroupContact.ts b/src/models/creation/CreateGroupContact.ts
index 73f43d0..d8aa815 100644
--- a/src/models/creation/CreateGroupContact.ts
+++ b/src/models/creation/CreateGroupContact.ts
@@ -1,5 +1,6 @@
 import { IsEmail, IsInt, IsNotEmpty, IsOptional, IsPhoneNumber, IsString } from 'class-validator';
 import { getConnectionManager } from 'typeorm';
+import { config } from '../../config';
 import { AddressNotFoundError, AddressWrongTypeError } from '../../errors/AddressErrors';
 import { Address } from '../entities/Address';
 import { GroupContact } from '../entities/GroupContact';
@@ -40,7 +41,7 @@ export class CreateGroupContact {
      * Optional
      */
     @IsOptional()
-    @IsPhoneNumber("DE")
+    @IsPhoneNumber(config.phone_validation_countrycode)
     phone?: string;
 
     /**
diff --git a/src/models/entities/GroupContact.ts b/src/models/entities/GroupContact.ts
index c7c8f18..08c5db3 100644
--- a/src/models/entities/GroupContact.ts
+++ b/src/models/entities/GroupContact.ts
@@ -8,6 +8,7 @@ import {
   IsString
 } from "class-validator";
 import { Column, Entity, ManyToOne, OneToMany, PrimaryGeneratedColumn } from "typeorm";
+import { config } from '../../config';
 import { Address } from "./Address";
 import { RunnerGroup } from "./RunnerGroup";
 
@@ -62,7 +63,7 @@ export class GroupContact {
    */
   @Column({ nullable: true })
   @IsOptional()
-  @IsPhoneNumber("DE")
+  @IsPhoneNumber(config.phone_validation_countrycode)
   phone?: string;
 
   /**
diff --git a/src/models/entities/Participant.ts b/src/models/entities/Participant.ts
index 2e40f5d..791b30d 100644
--- a/src/models/entities/Participant.ts
+++ b/src/models/entities/Participant.ts
@@ -8,6 +8,7 @@ import {
   IsString
 } from "class-validator";
 import { Column, Entity, ManyToOne, OneToMany, PrimaryGeneratedColumn, TableInheritance } from "typeorm";
+import { config } from '../../config';
 import { Address } from "./Address";
 import { Donation } from "./Donation";
 
@@ -62,7 +63,7 @@ export abstract class Participant {
    */
   @Column({ nullable: true })
   @IsOptional()
-  @IsPhoneNumber("DE")
+  @IsPhoneNumber(config.phone_validation_countrycode)
   phone?: string;
 
   /**