diff --git a/src/PdfCreator.ts b/src/PdfCreator.ts
index bf37a23..e2cfd4b 100644
--- a/src/PdfCreator.ts
+++ b/src/PdfCreator.ts
@@ -14,6 +14,10 @@ export class PdfCreator {
     private templateDir = path.join(__dirname, '/templates');
     private browser;
 
+    /**
+     * Main constructor.
+     * Initializes i18n(ext), Handlebars and puppeteer.
+     */
     constructor() {
         i18next
             .use(Backend)
@@ -34,6 +38,11 @@ export class PdfCreator {
         });
     }
 
+    /**
+     * Generate sponsoring contract pdfs.
+     * @param runner The runner you want to generate the contracts for.
+     * @param locale The locale used for the contracts (default:en)
+     */
     public async generateSponsoringContract(runner: Runner, locale: string = "en"): Promise<any> {
         i18next.changeLanguage(locale);
         const template_source = fs.readFileSync(`${this.templateDir}/sponsoring_contract.html`, 'utf8');
diff --git a/src/controllers/PdfController.ts b/src/controllers/PdfController.ts
index 1a8e0c1..3163e79 100644
--- a/src/controllers/PdfController.ts
+++ b/src/controllers/PdfController.ts
@@ -13,6 +13,7 @@ export class PdfController {
     @Post('/contracts')
     @OpenAPI({ description: "Generate Sponsoring contract pdfs from runner objects." })
     async generateContracts(@Body({ validate: true }) runner: Runner, @Res() res: any, @QueryParam("locale") locale: string) {
+        await this.pdf;
         const contracts = await this.pdf.generateSponsoringContract(runner, locale);
         res.setHeader('content-type', 'application/pdf');
         return await contracts;