diff --git a/frontends/dnet-is-application/src/app/dsm/dsm-add-api.dialog.html b/frontends/dnet-is-application/src/app/dsm/dsm-add-api.dialog.html
index 38ea91ec..309197d9 100644
--- a/frontends/dnet-is-application/src/app/dsm/dsm-add-api.dialog.html
+++ b/frontends/dnet-is-application/src/app/dsm/dsm-add-api.dialog.html
@@ -4,7 +4,7 @@
     <div mat-dialog-content>
         <mat-form-field appearance="fill" floatLabel="always" style="width: 100%;">
             <mat-label>Protocol</mat-label>
-            <mat-select matInput formControlName="protocol" required (selectionChange)="onChangeProtocol($event)">
+            <mat-select matInput formControlName="protocol" (selectionChange)="onChangeProtocol($event)">
                 <mat-option *ngFor="let i of protocols" [value]="i">{{i}}</mat-option>
             </mat-select>
             <mat-error *ngIf="addApiForm.get('protocol')?.invalid">This field is <strong>required</strong></mat-error>
@@ -12,7 +12,7 @@
 
         <mat-card style="margin-top: 10px;" *ngIf="selectedProtocol">
             <mat-card-header>
-              <mat-card-title>API Description</mat-card-title>
+                <mat-card-title>API Description</mat-card-title>
             </mat-card-header>
             <mat-card-content style="padding-top: 1em;">
                 <mat-form-field appearance="fill" floatLabel="always" style="width: 100%;">
@@ -24,52 +24,89 @@
                     <mat-label>Api ID (prefix)</mat-label>
                     <input matInput readonly value="{{apiPrefix}}" />
                 </mat-form-field>
-        
+
                 <mat-form-field appearance="fill" floatLabel="always" style="width: 70%;">
                     <mat-label>Api ID (suffix)</mat-label>
-                    <input matInput formControlName="apiId" required placeholder="example: {{selectedProtocol}}_01" />
-                    <mat-error *ngIf="addApiForm.get('apiId')?.invalid">This field is <strong>required</strong></mat-error>
+                    <input matInput formControlName="apiIdSuffix" placeholder="example: {{selectedProtocol}}_01" />
+                    <mat-error *ngIf="addApiForm.get('apiIdSuffix')?.invalid">This field is
+                        <strong>required</strong></mat-error>
                 </mat-form-field>
 
                 <mat-form-field appearance="fill" floatLabel="always" style="width: 50%;">
                     <mat-label>Compatibility level</mat-label>
-                    <mat-select matInput formControlName="compatibility" required>
+                    <mat-select matInput formControlName="compatibility">
                         <mat-option *ngFor="let i of compatibilityLevels" [value]="i">{{i}}</mat-option>
                     </mat-select>
-                    <mat-error *ngIf="addApiForm.get('compatibility')?.invalid">This field is <strong>required</strong></mat-error>
+                    <mat-error *ngIf="addApiForm.get('compatibility')?.invalid">This field is
+                        <strong>required</strong></mat-error>
                 </mat-form-field>
 
                 <mat-form-field appearance="fill" floatLabel="always" style="width: 50%;">
                     <mat-label>Content description</mat-label>
-                    <mat-select matInput formControlName="contentdescription" required>
+                    <mat-select matInput formControlName="contentdescription">
                         <mat-option *ngFor="let i of contentDescTypes" [value]="i">{{i}}</mat-option>
                     </mat-select>
-                    <mat-error *ngIf="addApiForm.get('contentdescription')?.invalid">This field is <strong>required</strong></mat-error>
+                    <mat-error *ngIf="addApiForm.get('contentdescription')?.invalid">This field is
+                        <strong>required</strong></mat-error>
                 </mat-form-field>
             </mat-card-content>
         </mat-card>
 
         <mat-card style="margin-top: 10px;" *ngIf="selectedProtocol">
             <mat-card-header>
-              <mat-card-title>Configuration Parameters</mat-card-title>
+                <mat-card-title>Configuration Parameters</mat-card-title>
             </mat-card-header>
             <mat-card-content style="padding-top: 1em;">
                 <mat-form-field appearance="fill" floatLabel="always" style="width: 100%;">
                     <mat-label>Base URL</mat-label>
-                    <input matInput formControlName="baseurl" required  />
-                    <mat-error *ngIf="addApiForm.get('baseurl')?.invalid">This field is <strong>required</strong></mat-error>
-                </mat-form-field>
-        
-                <mat-form-field appearance="fill" floatLabel="always" style="width: 100%;" *ngFor="let p of selProtParams">
-                    <mat-label>Protocol: {{selectedProtocol}} - Parameter: {{p.label}}</mat-label>
-                    <input matInput [formControlName]="paramPrefix + p.name" required  />
-                    <mat-error *ngIf="addApiForm.get(paramPrefix + p.name)?.invalid">Invalid value</mat-error>
+                    <input matInput formControlName="baseurl" />
+                    <mat-error *ngIf="addApiForm.get('baseurl')?.invalid">This field is
+                        <strong>required</strong></mat-error>
                 </mat-form-field>
 
+                <ng-container *ngFor="let p of selProtParams">
+                    <ng-container *ngIf="!p.hasSelFunction">
+                        <mat-form-field appearance="fill" floatLabel="always" style="width: 100%;"
+                            *ngIf="p.type != 'BOOLEAN'">
+                            <mat-label>
+                                <b>{{selectedProtocol}}</b> - {{p.label}}
+                                <b *ngIf="p.type == 'LIST'">(Comma separeted values)</b>
+                                <b *ngIf="p.type == 'INT'">(Numeric)</b>
+                            </mat-label>
+                            <input matInput [formControlName]="paramPrefix + p.name" />
+                            <mat-error *ngIf="addApiForm.get(paramPrefix + p.name)?.invalid">Invalid value</mat-error>
+                        </mat-form-field>
+                        <mat-form-field appearance="fill" floatLabel="always" style="width: 100%;"
+                            *ngIf="p.type == 'BOOLEAN'">
+                            <mat-label><b>{{selectedProtocol}}</b> - {{p.label}} <b>(true/false)</b></mat-label>
+                            <mat-select matInput [formControlName]="paramPrefix + p.name">
+                                <mat-option></mat-option>
+                                <mat-option value="true">true</mat-option>
+                                <mat-option value="false">false</mat-option>
+                            </mat-select>
+                            <mat-error *ngIf="addApiForm.get(paramPrefix + p.name)?.invalid">Invalid value</mat-error>
+                        </mat-form-field>
+                    </ng-container>
+
+                    <mat-form-field appearance="fill" floatLabel="always" style="width: 100%;" *ngIf="p.hasSelFunction">
+                        <mat-label><b>{{selectedProtocol}}</b> - {{p.label}} <b *ngIf="p.type == 'LIST'">(multiple choice)</b></mat-label>
+                        <mat-select matInput [formControlName]="paramPrefix + p.name" [multiple]="p.type == 'LIST'">
+                            <mat-option *ngIf="p.type != 'LIST'"></mat-option>
+                            <mat-option value="0">0 - TODO</mat-option>
+                            <mat-option value="1">1 - TODO</mat-option>
+                            <mat-option value="2">2 - TODO</mat-option>
+                            <mat-option value="3">3 - TODO</mat-option>
+                        </mat-select>
+                        <mat-error *ngIf="addApiForm.get(paramPrefix + p.name)?.invalid">Invalid value</mat-error>
+                    </mat-form-field>
+                </ng-container>
+
+
                 <mat-form-field appearance="fill" floatLabel="always" style="width: 100%;">
                     <mat-label>XPath for Metatadata Identifier</mat-label>
-                    <input matInput formControlName="metadataIdentifierPath" required />
-                    <mat-error *ngIf="addApiForm.get('metadataIdentifierPath')?.invalid">This field is <strong>required</strong></mat-error>
+                    <input matInput formControlName="metadataIdentifierPath" />
+                    <mat-error *ngIf="addApiForm.get('metadataIdentifierPath')?.invalid">This field is
+                        <strong>required</strong></mat-error>
                 </mat-form-field>
             </mat-card-content>
         </mat-card>
@@ -79,9 +116,9 @@
         <button mat-stroked-button color="primary" type="submit" [disabled]="!addApiForm.valid">Submit</button>
         <button mat-stroked-button color="primary" mat-dialog-close>Close</button>
         <mat-error *ngIf="addApiForm.errors?.['serverError']">
-          {{ addApiForm.errors?.['serverError'] }}
+            {{ addApiForm.errors?.['serverError'] }}
         </mat-error>
-      </div>
+    </div>
 </form>
 
 <!--
diff --git a/frontends/dnet-is-application/src/app/dsm/dsm.component.ts b/frontends/dnet-is-application/src/app/dsm/dsm.component.ts
index 153c2119..32ac9477 100644
--- a/frontends/dnet-is-application/src/app/dsm/dsm.component.ts
+++ b/frontends/dnet-is-application/src/app/dsm/dsm.component.ts
@@ -8,7 +8,7 @@ import { MatSort } from '@angular/material/sort';
 import { combineLatest } from 'rxjs';
 import { Router } from '@angular/router';
 import { PageEvent } from '@angular/material/paginator';
-import { FormBuilder, FormControl, FormGroup, Validators } from '@angular/forms';
+import { FormBuilder, FormControl, FormGroup, ValidatorFn, Validators } from '@angular/forms';
 import { MatSelectChange } from '@angular/material/select';
 
 @Component({
@@ -174,14 +174,13 @@ export class DsmAddApiDialog {
   protocolsMap:any = {};
   selProtParams:ProtocolParam[] = [];
 
-  apiIdControl = new FormControl('', [Validators.required]);
   addApiForm:FormGroup = new FormGroup({
-    apiId: this.apiIdControl,
-    compatibility : new FormControl(''),
-    contentdescription : new FormControl(''),
-    protocol : new FormControl(''),
-    baseurl : new FormControl(''),
-    metadataIdentifierPath : new FormControl('')
+    apiIdSuffix: new FormControl('', [Validators.required]),
+    compatibility : new FormControl('', [Validators.required]),
+    contentdescription : new FormControl('', [Validators.required]),
+    protocol : new FormControl('', [Validators.required]),
+    baseurl : new FormControl('', [Validators.required]),
+    metadataIdentifierPath : new FormControl('', [Validators.required])
   });
 
   constructor(public dialogRef: MatDialogRef<DsmAddApiDialog>,  @Inject(MAT_DIALOG_DATA) public data: any, public service: ISService) {
@@ -207,7 +206,12 @@ export class DsmAddApiDialog {
   
     if (this.protocolsMap[e.value]) {
       this.selProtParams = this.protocolsMap[e.value];
-      this.selProtParams.forEach(p => this.addApiForm.addControl(this.paramPrefix + p.name, new FormControl('')));
+      this.selProtParams.forEach(p => {
+        let validations:ValidatorFn[] = [];
+        if (!p.optional) { validations.push(Validators.required); }
+        if (p.type == 'INT') { validations.push(Validators.pattern('^[0-9]*$')); }
+        this.addApiForm.addControl(this.paramPrefix + p.name, new FormControl('', validations));
+      });
     } else {
       this.selProtParams = [];
     }
@@ -215,7 +219,7 @@ export class DsmAddApiDialog {
 
   onSubmit():void {
     let api:ApiInsert = {
-      id: this.apiPrefix + this.apiIdControl.value,
+      id: this.apiPrefix + this.addApiForm.get('apiIdSuffix')?.value,
       protocol: this.selectedProtocol,
       datasource: this.data.dsId,
       contentdescription: this.addApiForm.get('contentdescription')?.value,
@@ -232,7 +236,7 @@ export class DsmAddApiDialog {
         if (val) {
           api.apiParams.push({
             param: k.substring(this.paramPrefix.length),
-            value: val 
+            value: (Array.isArray(val)) ? val.join() : val
           });
         }
       }
diff --git a/frontends/dnet-is-application/src/app/protocols/protocols.component.html b/frontends/dnet-is-application/src/app/protocols/protocols.component.html
index f051df50..4cb904dd 100644
--- a/frontends/dnet-is-application/src/app/protocols/protocols.component.html
+++ b/frontends/dnet-is-application/src/app/protocols/protocols.component.html
@@ -39,7 +39,7 @@
 
         <!-- Row shown when there is no matching data. -->
         <tr class="mat-row" *matNoDataRow>
-            <td class="mat-cell" colspan="5">No parameters</td>
+            <td class="mat-cell" colspan="5" style="padding: 0 16px;">No parameters</td>
         </tr>
     </table>
 </div>
\ No newline at end of file