diff --git a/src/models/entities/Address.ts b/src/models/entities/Address.ts
index 561808f..dbb7eb3 100644
--- a/src/models/entities/Address.ts
+++ b/src/models/entities/Address.ts
@@ -80,4 +80,11 @@ export class Address {
    */
   @OneToMany(() => IAddressUser, addressUser => addressUser.address, { nullable: true })
   addressUsers: IAddressUser[];
+
+  /**
+   * Turns this entity into it's response class.
+   */
+  public toResponse() {
+    return new Error("NotImplemented");
+  }
 }
diff --git a/src/models/entities/DistanceDonation.ts b/src/models/entities/DistanceDonation.ts
index d263e90..6b9ba5d 100644
--- a/src/models/entities/DistanceDonation.ts
+++ b/src/models/entities/DistanceDonation.ts
@@ -39,4 +39,11 @@ export class DistanceDonation extends Donation {
     }
     return calculatedAmount;
   }
+
+  /**
+   * Turns this entity into it's response class.
+   */
+  public toResponse() {
+    return new Error("NotImplemented");
+  }
 }
diff --git a/src/models/entities/Donation.ts b/src/models/entities/Donation.ts
index eea23b5..46d7d45 100644
--- a/src/models/entities/Donation.ts
+++ b/src/models/entities/Donation.ts
@@ -32,4 +32,11 @@ export abstract class Donation {
    * The exact implementation may differ for each type of donation.
    */
   abstract amount: number;
+
+  /**
+   * Turns this entity into it's response class.
+   */
+  public toResponse() {
+    return new Error("NotImplemented");
+  }
 }
\ No newline at end of file
diff --git a/src/models/entities/Donor.ts b/src/models/entities/Donor.ts
index 188ed09..01b365c 100644
--- a/src/models/entities/Donor.ts
+++ b/src/models/entities/Donor.ts
@@ -1,5 +1,6 @@
 import { IsBoolean } from "class-validator";
 import { ChildEntity, Column, OneToMany } from "typeorm";
+import { ResponseDonor } from '../responses/ResponseDonor';
 import { Donation } from './Donation';
 import { Participant } from "./Participant";
 
@@ -22,4 +23,11 @@ export class Donor extends Participant {
  */
   @OneToMany(() => Donation, donation => donation.donor, { nullable: true })
   donations: Donation[];
+
+  /**
+   * Turns this entity into it's response class.
+   */
+  public toResponse(): ResponseDonor {
+    return new ResponseDonor(this);
+  }
 }
\ No newline at end of file
diff --git a/src/models/entities/FixedDonation.ts b/src/models/entities/FixedDonation.ts
index db53e2f..6a32066 100644
--- a/src/models/entities/FixedDonation.ts
+++ b/src/models/entities/FixedDonation.ts
@@ -16,4 +16,11 @@ export class FixedDonation extends Donation {
   @IsInt()
   @IsPositive()
   amount: number;
+
+  /**
+   * Turns this entity into it's response class.
+   */
+  public toResponse() {
+    return new Error("NotImplemented");
+  }
 }
\ No newline at end of file
diff --git a/src/models/entities/GroupContact.ts b/src/models/entities/GroupContact.ts
index 4dbcc5e..f650259 100644
--- a/src/models/entities/GroupContact.ts
+++ b/src/models/entities/GroupContact.ts
@@ -81,4 +81,11 @@ export class GroupContact implements IAddressUser {
     */
   @OneToMany(() => RunnerGroup, group => group.contact, { nullable: true })
   groups: RunnerGroup[];
+
+  /**
+   * Turns this entity into it's response class.
+   */
+  public toResponse() {
+    return new Error("NotImplemented");
+  }
 }
\ No newline at end of file
diff --git a/src/models/entities/IAddressUser.ts b/src/models/entities/IAddressUser.ts
index 3a7762a..3d8eaf9 100644
--- a/src/models/entities/IAddressUser.ts
+++ b/src/models/entities/IAddressUser.ts
@@ -12,4 +12,9 @@ export abstract class IAddressUser {
 
     @ManyToOne(() => Address, address => address.addressUsers, { nullable: true })
     address?: Address
+
+    /**
+   * Turns this entity into it's response class.
+   */
+    public abstract toResponse();
 }
diff --git a/src/models/entities/Participant.ts b/src/models/entities/Participant.ts
index de13b5f..fa40a8f 100644
--- a/src/models/entities/Participant.ts
+++ b/src/models/entities/Participant.ts
@@ -9,6 +9,7 @@ import {
 } from "class-validator";
 import { Column, Entity, ManyToOne, PrimaryGeneratedColumn, TableInheritance } from "typeorm";
 import { config } from '../../config';
+import { ResponseParticipant } from '../responses/ResponseParticipant';
 import { Address } from "./Address";
 import { IAddressUser } from './IAddressUser';
 
@@ -74,4 +75,9 @@ export abstract class Participant implements IAddressUser {
   @IsOptional()
   @IsEmail()
   email?: string;
+
+  /**
+   * Turns this entity into it's response class.
+   */
+  public abstract toResponse(): ResponseParticipant;
 }
\ No newline at end of file
diff --git a/src/models/entities/Permission.ts b/src/models/entities/Permission.ts
index 6a07312..4bba550 100644
--- a/src/models/entities/Permission.ts
+++ b/src/models/entities/Permission.ts
@@ -6,6 +6,7 @@ import {
 import { Column, Entity, ManyToOne, PrimaryGeneratedColumn } from "typeorm";
 import { PermissionAction } from '../enums/PermissionAction';
 import { PermissionTarget } from '../enums/PermissionTargets';
+import { ResponsePermission } from '../responses/ResponsePermission';
 import { Principal } from './Principal';
 /**
  * Defines the Permission entity.
@@ -51,4 +52,11 @@ export class Permission {
   public toString(): string {
     return this.target + ":" + this.action;
   }
+
+  /**
+   * Turns this entity into it's response class.
+   */
+  public toResponse(): ResponsePermission {
+    return new ResponsePermission(this);
+  }
 }
\ No newline at end of file
diff --git a/src/models/entities/Runner.ts b/src/models/entities/Runner.ts
index 5c51c11..f391103 100644
--- a/src/models/entities/Runner.ts
+++ b/src/models/entities/Runner.ts
@@ -1,5 +1,6 @@
 import { IsInt, IsNotEmpty } from "class-validator";
 import { ChildEntity, ManyToOne, OneToMany } from "typeorm";
+import { ResponseRunner } from '../responses/ResponseRunner';
 import { DistanceDonation } from "./DistanceDonation";
 import { Participant } from "./Participant";
 import { RunnerCard } from "./RunnerCard";
@@ -66,4 +67,11 @@ export class Runner extends Participant {
   public get distanceDonationAmount(): number {
     return this.distanceDonations.reduce((sum, current) => sum + current.amountPerDistance, 0) * this.distance;
   }
+
+  /**
+   * Turns this entity into it's response class.
+   */
+  public toResponse(): ResponseRunner {
+    return new ResponseRunner(this);
+  }
 }
\ No newline at end of file
diff --git a/src/models/entities/RunnerCard.ts b/src/models/entities/RunnerCard.ts
index 5f48257..4ea40e2 100644
--- a/src/models/entities/RunnerCard.ts
+++ b/src/models/entities/RunnerCard.ts
@@ -57,4 +57,11 @@ export class RunnerCard {
    */
   @OneToMany(() => TrackScan, scan => scan.track, { nullable: true })
   scans: TrackScan[];
+
+  /**
+   * Turns this entity into it's response class.
+   */
+  public toResponse() {
+    return new Error("NotImplemented");
+  }
 }
diff --git a/src/models/entities/RunnerGroup.ts b/src/models/entities/RunnerGroup.ts
index b5bcfcd..5620aca 100644
--- a/src/models/entities/RunnerGroup.ts
+++ b/src/models/entities/RunnerGroup.ts
@@ -5,6 +5,7 @@ import {
   IsString
 } from "class-validator";
 import { Column, Entity, ManyToOne, OneToMany, PrimaryGeneratedColumn, TableInheritance } from "typeorm";
+import { ResponseRunnerGroup } from '../responses/ResponseRunnerGroup';
 import { GroupContact } from "./GroupContact";
 import { Runner } from "./Runner";
 
@@ -60,4 +61,9 @@ export abstract class RunnerGroup {
   public get distanceDonationAmount(): number {
     return this.runners.reduce((sum, current) => sum + current.distanceDonationAmount, 0);
   }
+
+  /**
+   * Turns this entity into it's response class.
+   */
+  public abstract toResponse(): ResponseRunnerGroup;
 }
\ No newline at end of file