diff --git a/ccm-core-apiclient/src/main/typescript/clients/groups-api.ts b/ccm-core-apiclient/src/main/typescript/clients/groups-api.ts
index b0f10e423..d042f0ba2 100644
--- a/ccm-core-apiclient/src/main/typescript/clients/groups-api.ts
+++ b/ccm-core-apiclient/src/main/typescript/clients/groups-api.ts
@@ -4,10 +4,20 @@ import {
     ListView,
 } from "@libreccm/ccm-apiclient-commons";
 
-import { Group, buildGroupFromRecord } from "../entities/group";
+import { buildIdentifierParam } from "@libreccm/ccm-apiclient-commons";
+
+import {
+    Group,
+    buildGroupFromRecord,
+    buildGroupUserMembershipFromRecord,
+    GroupUserMembership,
+} from "../entities/group";
 
 import * as Constants from "../constants";
-import { buildPartyRoleMembershipFromRecord } from "../entities/party";
+import {
+    buildPartyRoleMembershipFromRecord,
+    PartyRoleMembership,
+} from "../entities/party";
 import { buildRoleFromRecord } from "../entities/role";
 
 /**
@@ -60,10 +70,12 @@ export class GroupsApiClient {
         }
     }
 
-    async getGroup(groupIdentifier: string): Promise<Group> {
+    async getGroup(groupIdentifier: string | number): Promise<Group> {
         try {
             const response: ApiResponse = await this.#apiClient.get(
-                `${this.#GROUPS_API_PREFIX}/${groupIdentifier}`
+                `${this.#GROUPS_API_PREFIX}/${buildIdentifierParam(
+                    groupIdentifier
+                )}`
             );
 
             if (response.ok) {
@@ -79,5 +91,269 @@ export class GroupsApiClient {
         }
     }
 
-    
+    async addGroup(group: Group): Promise<string> {
+        try {
+            const response: ApiResponse = await this.#apiClient.post(
+                `${this.#GROUPS_API_PREFIX}`,
+                JSON.stringify(group)
+            );
+            if (response.ok) {
+                return group.name;
+            } else {
+                throw `Failed to add group ${group.name}: 
+                ${response.status} ${response.statusText}`;
+            }
+        } catch (err) {
+            throw `Failed to add group ${group.name}: ${err}`;
+        }
+    }
+
+    async updateGroup(groupIdentifier: string, group: Group): Promise<void> {
+        try {
+            const response: ApiResponse = await this.#apiClient.put(
+                `${this.#GROUPS_API_PREFIX}/${buildIdentifierParam(
+                    groupIdentifier
+                )}`,
+                JSON.stringify(group)
+            );
+            if (response.ok) {
+                return;
+            } else {
+                throw `Failed to update group ${groupIdentifier}: 
+                ${response.status} ${response.statusText}`;
+            }
+        } catch (err) {
+            throw `Failed to update group ${groupIdentifier}: ${err}`;
+        }
+    }
+
+    async deleteGroup(groupIdentifier: string): Promise<void> {
+        try {
+            const response: ApiResponse = await this.#apiClient.delete(
+                `${this.#GROUPS_API_PREFIX}/${buildIdentifierParam(
+                    groupIdentifier
+                )}`
+            );
+            if (response.ok) {
+                return;
+            } else {
+                throw `Failed to delete group ${name}: 
+                ${response.status} ${response.statusText}`;
+            }
+        } catch (err) {
+            throw `Failed to delete group ${name}: ${err}`;
+        }
+    }
+
+    async deleteGroupById(groupId: number): Promise<void> {
+        try {
+            const response: ApiResponse = await this.#apiClient.delete(
+                `${this.#GROUPS_API_PREFIX}/ID-${groupId}`
+            );
+            if (response.ok) {
+                return;
+            } else {
+                throw `Failed to delete group ${groupId}: 
+                ${response.status} ${response.statusText}`;
+            }
+        } catch (err) {
+            throw `Failed to delete group ${groupId}: ${err}`;
+        }
+    }
+
+    async deleteGroupByUuid(groupUuid: number): Promise<void> {
+        try {
+            const response: ApiResponse = await this.#apiClient.delete(
+                `${this.#GROUPS_API_PREFIX}/UUID-${groupUuid}`
+            );
+            if (response.ok) {
+                return;
+            } else {
+                throw `Failed to delete group ${groupUuid}: 
+                ${response.status} ${response.statusText}`;
+            }
+        } catch (err) {
+            throw `Failed to delete group ${groupUuid}: ${err}`;
+        }
+    }
+
+    async getMembers(
+        groupIdentifier: string,
+        limit: number,
+        offset: number
+    ): Promise<ListView<GroupUserMembership>> {
+        try {
+            const groupParam: string = buildIdentifierParam(groupIdentifier);
+
+            const response: ApiResponse = await this.#apiClient.get(
+                `${this.#GROUPS_API_PREFIX}/${groupParam}/members`,
+                {
+                    limit: limit.toString(),
+                    offset: offset.toString(),
+                }
+            );
+            if (response.ok) {
+                const result: Record<
+                    string,
+                    unknown
+                > = (await response.json()) as Record<string, unknown>;
+                const list: Record<string, unknown>[] = result.list as Record<
+                    string,
+                    unknown
+                >[];
+                const members: GroupUserMembership[] = list.map((record) =>
+                    buildGroupUserMembershipFromRecord(record)
+                );
+
+                return {
+                    list: members,
+                    count: result.count as number,
+                    limit: result.limit as number,
+                    offset: result.offset as number,
+                };
+            } else {
+                throw `Failed to get members of group ${groupIdentifier}: 
+                ${response.status} ${response.statusText}`;
+            }
+        } catch (err) {
+            throw `Failed to get members of group ${groupIdentifier}: ${err}`;
+        }
+    }
+
+    async addMember(
+        groupIdentifier: string | number,
+        userIdentifier: string | number
+    ): Promise<void> {
+        try {
+            const groupParam = buildIdentifierParam(groupIdentifier);
+            const memberParam = buildIdentifierParam(userIdentifier);
+            const response: ApiResponse = await this.#apiClient.put(
+                `${
+                    this.#GROUPS_API_PREFIX
+                }/${groupParam}/members/${memberParam}`
+            );
+            if (response.ok) {
+                return;
+            } else {
+                throw `Failed to add user ${userIdentifier} to 
+                group ${groupIdentifier}: 
+                ${response.status} ${response.statusText}`;
+            }
+        } catch (err) {
+            throw `Failed to add user ${userIdentifier} to 
+            group ${groupIdentifier}: ${err}`;
+        }
+    }
+
+    async removeMember(
+        groupIdentifier: string | number,
+        userIdentifier: string | number
+    ): Promise<void> {
+        try {
+            const groupParam = buildIdentifierParam(groupIdentifier);
+            const memberParam = buildIdentifierParam(userIdentifier);
+            const response: ApiResponse = await this.#apiClient.delete(
+                `${
+                    this.#GROUPS_API_PREFIX
+                }/${groupParam}/members/${memberParam}`
+            );
+            if (response.ok) {
+                return;
+            } else {
+                throw `Failed to remove user ${userIdentifier} from 
+                group ${groupIdentifier}: 
+                ${response.status} ${response.statusText}`;
+            }
+        } catch (err) {
+            throw `Failed to remote user ${userIdentifier} from 
+            group ${groupIdentifier}: ${err}`;
+        }
+    }
+
+    async getRoles(
+        groupIdentifier: string
+    ): Promise<ListView<PartyRoleMembership>> {
+        const groupParam: string = buildIdentifierParam(groupIdentifier);
+
+        try {
+            const response: ApiResponse = await this.#apiClient.get(
+                `${this.#GROUPS_API_PREFIX}/${groupParam}/roles`
+            );
+            if (response.ok) {
+                const result: Record<
+                    string,
+                    unknown
+                > = (await response.json()) as Record<string, unknown>;
+                const list: Record<string, unknown>[] = result.list as Record<
+                    string,
+                    unknown
+                >[];
+                const roles: PartyRoleMembership[] = list.map((record) =>
+                    buildPartyRoleMembershipFromRecord(record)
+                );
+
+                return {
+                    list: roles,
+                    count: result.count as number,
+                    limit: result.limit as number,
+                    offset: result.offset as number,
+                };
+            } else {
+                throw `Failed to get roles of group ${groupIdentifier}: 
+                ${response.status} ${response.statusText}`;
+            }
+        } catch (err) {
+            throw `Failed to get roles of group ${groupIdentifier}: ${err}`;
+        }
+    }
+
+    async addRole(
+        groupIdentifier: string | number,
+        roleIdentifier: string | number
+    ): Promise<void> {
+        try {
+            const groupParam = buildIdentifierParam(groupIdentifier);
+            const roleParam = buildIdentifierParam(roleIdentifier);
+            const response: ApiResponse = await this.#apiClient.put(
+                `${
+                    this.#GROUPS_API_PREFIX
+                }/${groupParam}/roles/${roleParam}`
+            );
+            if (response.ok) {
+                return;
+            } else {
+                throw `Failed to add role ${roleIdentifier} to 
+                group ${groupIdentifier}: 
+                ${response.status} ${response.statusText}`;
+            }
+        } catch (err) {
+            throw `Failed to add role ${roleIdentifier} to 
+            group ${groupIdentifier}: ${err}`;
+        }
+    }
+
+    async removeRole(
+        groupIdentifier: string | number,
+        roleIdentifier: string | number
+    ): Promise<void> {
+        try {
+            const groupParam = buildIdentifierParam(groupIdentifier);
+            const roleParam = buildIdentifierParam(roleIdentifier);
+            const response: ApiResponse = await this.#apiClient.delete(
+                `${
+                    this.#GROUPS_API_PREFIX
+                }/${groupParam}/roles/${roleParam}`
+            );
+            if (response.ok) {
+                return;
+            } else {
+                throw `Failed to remove role ${roleIdentifier} from 
+                group ${groupIdentifier}: 
+                ${response.status} ${response.statusText}`;
+            }
+        } catch (err) {
+            throw `Failed to remote role ${roleIdentifier} from 
+            group ${groupIdentifier}: ${err}`;
+        }
+    }
 }