diff --git a/api/eslint.config.mjs b/api/eslint.config.mjs
index 6bc17acc..8a7f28e0 100644
--- a/api/eslint.config.mjs
+++ b/api/eslint.config.mjs
@@ -20,8 +20,9 @@ export default [
         languageOptions: {
             parser: tsParser,
         },
-	rules: { 
-		"@typescript-eslint/no-require-imports": "off" 
+	rules: {
+		"@typescript-eslint/no-require-imports": "off",
+		"@typescript-eslint/triple-slash-reference": "off"
 	},
     }
 ];
diff --git a/api/package-lock.json b/api/package-lock.json
index 55998565..ea5dedd6 100644
--- a/api/package-lock.json
+++ b/api/package-lock.json
@@ -44,8 +44,10 @@
       "devDependencies": {
         "@types/express": "^5.0.6",
         "@types/express-session": "^1.18.2",
+        "@types/ini": "^4.1.1",
         "@types/jest": "^30",
         "@types/node": "^26",
+        "@types/pdfkit": "^0.17.6",
         "@typescript-eslint/eslint-plugin": "^8.52",
         "@typescript-eslint/parser": "^8.52",
         "eslint": "^10",
@@ -2485,6 +2487,13 @@
       "integrity": "sha512-r8Tayk8HJnX0FztbZN7oVqGccWgw98T/0neJphO91KkmOzug1KkofZURD4UaD5uH8AqcFLfdPErnBod0u71/qg==",
       "license": "MIT"
     },
+    "node_modules/@types/ini": {
+      "version": "4.1.1",
+      "resolved": "https://registry.npmjs.org/@types/ini/-/ini-4.1.1.tgz",
+      "integrity": "sha512-MIyNUZipBTbyUNnhvuXJTY7B6qNI78meck9Jbv3wk0OgNwRyOOVEKDutAkOs1snB/tx0FafyR6/SN4Ps0hZPeg==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@types/istanbul-lib-coverage": {
       "version": "2.0.6",
       "resolved": "https://registry.npmjs.org/@types/istanbul-lib-coverage/-/istanbul-lib-coverage-2.0.6.tgz",
@@ -2570,6 +2579,16 @@
         "@types/passport": "*"
       }
     },
+    "node_modules/@types/pdfkit": {
+      "version": "0.17.6",
+      "resolved": "https://registry.npmjs.org/@types/pdfkit/-/pdfkit-0.17.6.tgz",
+      "integrity": "sha512-tIwzxk2uWKp0Cq9JIluQXJid77lYhF52EsIOwhsMF4iWLA6YneoBR1xVKYYdAysHuepUB0OX4tdwMiUDdGKmig==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/node": "*"
+      }
+    },
     "node_modules/@types/qs": {
       "version": "6.15.1",
       "resolved": "https://registry.npmjs.org/@types/qs/-/qs-6.15.1.tgz",
diff --git a/api/package.json b/api/package.json
index 3786c70a..7bb2f85e 100644
--- a/api/package.json
+++ b/api/package.json
@@ -56,6 +56,9 @@
   "devDependencies": {
     "@types/express": "^5.0.6",
     "@types/express-session": "^1.18.2",
+    "@types/ini": "^4.1.1",
+    "@types/jest": "^30.0.0",
+    "@types/pdfkit": "^0.17.6",
     "@types/jest": "^30",
     "@types/node": "^26",
     "@typescript-eslint/eslint-plugin": "^8.52",
diff --git a/api/src/app.ts b/api/src/app.ts
index bc3c8a7d..cd752cf1 100644
--- a/api/src/app.ts
+++ b/api/src/app.ts
@@ -1,7 +1,7 @@
-import * as express from "express";
-import * as cookieParser from "cookie-parser";
+import express from "express";
+import cookieParser from "cookie-parser";
 import * as path from "path";
-import * as logger from "morgan";
+import logger from "morgan";
 import Config from "./models/Config";
 
 const app = express();
diff --git a/api/src/jobs/Derivative.test.ts b/api/src/jobs/Derivative.test.ts
index 7df53718..e614509e 100644
--- a/api/src/jobs/Derivative.test.ts
+++ b/api/src/jobs/Derivative.test.ts
@@ -16,8 +16,8 @@ describe("Derivative", () => {
 
     describe("run", () => {
         let job: Job;
-        let consoleErrorSpy;
-        let consoleLogSpy;
+        let consoleErrorSpy: jest.SpyInstance;
+        let consoleLogSpy: jest.SpyInstance;
         beforeEach(() => {
             job = {
                 data: {
diff --git a/api/src/jobs/Derivative.ts b/api/src/jobs/Derivative.ts
index 829310b4..ec37f745 100644
--- a/api/src/jobs/Derivative.ts
+++ b/api/src/jobs/Derivative.ts
@@ -12,7 +12,7 @@ class Derivative implements QueueJob {
 
         // For each page
         const order = PageOrder.fromJob(job.data);
-        const generatingPromises = [];
+        const generatingPromises: Promise<string>[] = [];
         order.raw.forEach((page) => {
             // For each size
             const image = ImageFile.build(`${job.data.dir}/${page.filename}`);
diff --git a/api/src/models/AudioFile.ts b/api/src/models/AudioFile.ts
index 4d8f8744..40e26eb3 100644
--- a/api/src/models/AudioFile.ts
+++ b/api/src/models/AudioFile.ts
@@ -8,7 +8,7 @@ class AudioFile extends AbstractAVFile {
         return new AudioFile(filename, dir, Config.getInstance());
     }
 
-    static fromRaw(raw: Record<string, string>, config: Config = null): AudioFile {
+    static fromRaw(raw: Record<string, string>, config: Config | null = null): AudioFile {
         return new AudioFile(raw.filename, raw.label, config ?? Config.getInstance());
     }
 }
diff --git a/api/src/models/Category.ts b/api/src/models/Category.ts
index 96f215a1..a4b9e22b 100644
--- a/api/src/models/Category.ts
+++ b/api/src/models/Category.ts
@@ -5,7 +5,7 @@ import path = require("path");
 
 import Job from "./Job";
 
-export class CategoryRaw {
+export interface CategoryRaw {
     category: string;
     jobs: Array<string>;
 }
diff --git a/api/src/models/Config.ts b/api/src/models/Config.ts
index 49f7bc6e..43898146 100644
--- a/api/src/models/Config.ts
+++ b/api/src/models/Config.ts
@@ -2,7 +2,7 @@ import fs = require("fs");
 import ini = require("ini");
 import { FedoraModel, License } from "../services/FedoraCatalog";
 
-type ConfigValue = string | string[] | ConfigRecord;
+type ConfigValue = string | string[] | ConfigRecord | ConfigRecord[] | License;
 interface ConfigRecord {
     [key: string]: ConfigValue;
 }
@@ -10,7 +10,7 @@ interface ConfigRecord {
 class Config {
     private static instance: Config;
 
-    protected ini;
+    protected ini: ConfigRecord;
 
     constructor(ini: ConfigRecord) {
         this.ini = ini;
@@ -37,117 +37,117 @@ class Config {
     }
 
     get backendUrl(): string {
-        return this.ini["backend_url"] ?? "http://localhost:9000";
+        return (this.ini["backend_url"] ?? "http://localhost:9000") as string;
     }
 
     get clientUrl(): string {
-        return this.ini["client_url"];
+        return this.ini["client_url"] as string;
     }
 
     get fedoraUsername(): string {
-        return this.ini["fedora_username"];
+        return this.ini["fedora_username"] as string;
     }
 
     get fedoraPassword(): string {
-        return this.ini["fedora_password"];
+        return this.ini["fedora_password"] as string;
     }
 
     get fedoraPidNameSpace(): string {
-        return this.ini["fedora_pid_namespace"];
+        return this.ini["fedora_pid_namespace"] as string;
     }
 
     get ffmpegPath(): string {
-        return this.ini["ffmpeg_path"];
+        return this.ini["ffmpeg_path"] as string;
     }
 
     get fitsCommand(): string {
-        return this.ini["fits_command"];
+        return this.ini["fits_command"] as string;
     }
 
     get sessionKey(): string {
-        return this.ini["session_key"] ?? "vanilla hot cocoa";
+        return (this.ini["session_key"] ?? "vanilla hot cocoa") as string;
     }
 
     get tesseractPath(): string {
-        return this.ini["tesseract_path"];
+        return this.ini["tesseract_path"] as string;
     }
 
     get tesseractAllowedChars(): string {
-        return this.ini["tesseract_allowed_characters"];
+        return this.ini["tesseract_allowed_characters"] as string;
     }
 
     get vufindUrl(): string {
-        return this.ini["vufind_url"] ?? "";
+        return (this.ini["vufind_url"] ?? "") as string;
     }
 
     get pdfDirectory(): string {
-        return this.ini["pdf_directory"];
+        return this.ini["pdf_directory"] as string;
     }
 
     get textcleanerPath(): string {
-        return this.ini["textcleaner_path"];
+        return this.ini["textcleaner_path"] as string;
     }
 
     get textcleanerSwitches(): string {
-        return this.ini["textcleaner_switches"];
+        return this.ini["textcleaner_switches"] as string;
     }
 
     get holdingArea(): string {
-        const holdingArea = this.ini["holding_area_path"];
+        const holdingArea = this.ini["holding_area_path"] as string;
         return holdingArea.endsWith("/") ? holdingArea : holdingArea + "/";
     }
 
     get ocrmypdfPath(): string {
-        return this.ini["ocrmypdf_path"];
+        return this.ini["ocrmypdf_path"] as string;
     }
 
     get processedAreaPath(): string {
-        return this.ini["processed_area_path"];
+        return this.ini["processed_area_path"] as string;
     }
 
     get restBaseUrl(): string {
-        return this.ini["base_url"];
+        return this.ini["base_url"] as string;
     }
 
     get javaPath(): string {
-        return this.ini["java_path"] ?? "java";
+        return (this.ini["java_path"] ?? "java") as string;
     }
 
-    get tikaConfigFile(): string {
-        return this.ini["tika_config_file"] ?? null;
+    get tikaConfigFile(): string | null {
+        return (this.ini["tika_config_file"] ?? null) as string | null;
     }
 
     get tikaPath(): string {
-        return this.ini["tika_path"];
+        return this.ini["tika_path"] as string;
     }
 
     get solrCore(): string {
-        return this.ini["solr_core"] ?? "biblio";
+        return (this.ini["solr_core"] ?? "biblio") as string;
     }
 
     get solrUrl(): string {
-        return this.ini["solr_url"] ?? "http://localhost:8983/solr";
+        return (this.ini["solr_url"] ?? "http://localhost:8983/solr") as string;
     }
 
     get solrDocumentCacheDir(): boolean | string {
-        return this.ini["solr_document_cache_dir"] ?? false;
+        return (this.ini["solr_document_cache_dir"] ?? false) as boolean | string;
     }
 
     get allowedOrigins(): string[] {
-        return this.ini["allowed_origins"] ?? [];
+        return (this.ini["allowed_origins"] ?? []) as string[];
     }
 
     get pidNamespace(): string {
-        return this.ini["fedora_pid_namespace"] ?? "vudl";
+        return (this.ini["fedora_pid_namespace"] ?? "vudl") as string;
     }
 
     get initialPidValue(): number {
-        return parseInt(this.ini["fedora_initial_pid"] ?? "0");
+        return parseInt((this.ini["fedora_initial_pid"] ?? "0") as string);
     }
 
     get dataModels(): Record<string, string> {
         return (
-            this.ini["data_models"] ?? {
+            (this.ini["data_models"] as Record<string, string> | undefined) ?? {
                 Image: "vudl-system:ImageData",
                 PDF: "vudl-system:PDFData",
                 DOC: "vudl-system:DOCData",
@@ -161,7 +161,7 @@ class Config {
 
     get collectionModels(): Record<string, string> {
         return (
-            this.ini["collection_models"] ?? {
+            (this.ini["collection_models"] as Record<string, string> | undefined) ?? {
                 List: "vudl-system:ListCollection",
                 Resource: "vudl-system:ResourceCollection",
                 Folder: "vudl-system:FolderCollection",
@@ -170,27 +170,27 @@ class Config {
     }
 
     get institution(): string {
-        return this.ini["institution"] ?? "My University";
+        return (this.ini["institution"] ?? "My University") as string;
     }
 
     get collection(): string {
-        return this.ini["collection"] ?? "Digital Library";
+        return (this.ini["collection"] ?? "Digital Library") as string;
     }
 
     get topLevelPids(): Array<string> {
-        return this.ini["top_level_pids"] ?? [];
+        return (this.ini["top_level_pids"] ?? []) as string[];
     }
 
     get articlesToStrip(): Array<string> {
-        return this.ini["articles_to_strip"] ?? [];
+        return (this.ini["articles_to_strip"] ?? []) as string[];
     }
 
     get trashPid(): string | null {
-        return this.ini["trash_pid"] ?? null;
+        return (this.ini["trash_pid"] ?? null) as string | null;
     }
 
     get favoritePids(): Array<string> {
-        const favorites = this.ini["favorite_pids"] ?? [];
+        const favorites = (this.ini["favorite_pids"] ?? []) as string[];
         const trash = this.trashPid;
         if (trash && !favorites.includes(trash)) {
             favorites.push(trash);
@@ -199,23 +199,23 @@ class Config {
     }
 
     get languageMap(): Record<string, string> {
-        return this.ini["LanguageMap"] ?? {};
+        return (this.ini["LanguageMap"] ?? {}) as Record<string, string>;
     }
 
     get minimumValidYear(): number {
-        return parseInt(this.ini["minimum_valid_year"] ?? 1000);
+        return parseInt((this.ini["minimum_valid_year"] ?? "1000") as string);
     }
 
     get models(): Record<string, FedoraModel> {
-        return this.ini["models"] || {};
+        return (this.ini["models"] || {}) as Record<string, FedoraModel>;
     }
 
     get databaseSettings(): ConfigRecord {
-        return this.ini["Database"] ?? {};
+        return (this.ini["Database"] ?? {}) as ConfigRecord;
     }
 
     get databaseClient(): string {
-        return (this.databaseSettings["client"] as string) ?? "sqlite3";
+        return (this.databaseSettings["client"] ?? "sqlite3") as string;
     }
 
     get databaseConnectionSettings(): ConfigRecord {
@@ -223,15 +223,15 @@ class Config {
     }
 
     get authenticationSettings(): ConfigRecord {
-        return this.ini["Authentication"] ?? [];
+        return (this.ini["Authentication"] ?? {}) as ConfigRecord;
     }
 
     get authenticationStrategy(): string {
-        return (this.authenticationSettings["strategy"] as string) ?? "local";
+        return (this.authenticationSettings["strategy"] ?? "local") as string;
     }
 
     get authenticationHashAlgorithm(): string {
-        return (this.authenticationSettings["hash_algorithm"] as string) ?? "sha1";
+        return (this.authenticationSettings["hash_algorithm"] ?? "sha1") as string;
     }
 
     get authenticationLegalUsernames(): Array<string> {
@@ -242,12 +242,12 @@ class Config {
         if (typeof this.authenticationSettings["require_passwords"] === "boolean") {
             return this.authenticationSettings["require_passwords"];
         }
-        const stringValue = (this.authenticationSettings["require_passwords"] as string) ?? "true";
+        const stringValue = (this.authenticationSettings["require_passwords"] ?? "true") as string;
         return stringValue.trim().toLowerCase() !== "false";
     }
 
     get authenticationSalt(): string {
-        return (this.authenticationSettings["salt"] as string) ?? "VuDLSaltValue";
+        return (this.authenticationSettings["salt"] ?? "VuDLSaltValue") as string;
     }
 
     get databaseInitialUsers(): Record<string, string> {
@@ -255,96 +255,99 @@ class Config {
     }
 
     get samlCertificate(): string {
-        return (this.authenticationSettings["saml_certificate"] as string) ?? "";
+        return (this.authenticationSettings["saml_certificate"] ?? "") as string;
     }
 
     get samlEntryPoint(): string {
-        return (this.authenticationSettings["saml_entry_point"] as string) ?? "";
+        return (this.authenticationSettings["saml_entry_point"] ?? "") as string;
     }
 
     get licenses(): Record<string, License> {
-        return this.ini["licenses"] ?? {};
+        return (this.ini["licenses"] ?? {}) as Record<string, License>;
     }
 
     get agentDefaults(): Record<string, string> {
-        return this.ini?.["agent"]?.["defaults"] ?? {};
+        return ((this.ini["agent"] as ConfigRecord | undefined)?.["defaults"] ?? {}) as Record<string, string>;
     }
 
     get agentRoles(): Array<string> {
-        return this.ini?.["agent"]?.["roles"] ?? [];
+        return ((this.ini["agent"] as ConfigRecord | undefined)?.["roles"] ?? []) as string[];
     }
 
     get agentTypes(): Array<string> {
-        return this.ini?.["agent"]?.["types"] ?? [];
+        return ((this.ini["agent"] as ConfigRecord | undefined)?.["types"] ?? []) as string[];
     }
 
     get dublinCoreFields(): Record<string, Record<string, string | Array<string>>> {
-        return this.ini?.["dublin_core"] ?? {};
+        return (this.ini["dublin_core"] ?? {}) as Record<string, Record<string, string | Array<string>>>;
     }
 
     get redisConnectionSettings(): Record<string, string> {
-        return this.ini?.["queue"]?.["connection"] ?? {};
+        return ((this.ini["queue"] as ConfigRecord | undefined)?.["connection"] ?? {}) as Record<string, string>;
     }
 
     get redisDefaultQueueName(): string {
-        return this.ini?.["queue"]?.["defaultQueueName"] ?? "vudl";
+        return ((this.ini["queue"] as ConfigRecord | undefined)?.["defaultQueueName"] ?? "vudl") as string;
     }
 
     get redisQueueJobMap(): Record<string, string> {
-        return this.ini?.["queue"]?.["jobMap"] ?? {};
+        return ((this.ini["queue"] as ConfigRecord | undefined)?.["jobMap"] ?? {}) as Record<string, string>;
     }
 
     get redisLockDuration(): number {
-        return parseInt(this.ini?.["queue"]?.["lockDuration"] ?? "30000");
+        return parseInt(((this.ini["queue"] as ConfigRecord | undefined)?.["lockDuration"] ?? "30000") as string);
     }
 
     get processMetadataDefaults(): Record<string, string> {
-        return this.ini?.["process_metadata_defaults"] ?? {};
+        return (this.ini["process_metadata_defaults"] ?? {}) as Record<string, string>;
     }
 
     get toolPresets(): Array<Record<string, string>> {
-        return this.ini?.["tool_presets"] ?? [];
+        return (this.ini["tool_presets"] ?? []) as Array<Record<string, string>>;
     }
 
     get sharpOptions(): Record<string, unknown> {
-        const pixelLimit = this.ini?.["sharp"]?.["limitInputPixels"] ?? "268402689";
+        const pixelLimit = ((this.ini["sharp"] as ConfigRecord | undefined)?.["limitInputPixels"] ??
+            "268402689") as string;
         return {
             limitInputPixels: parseInt(pixelLimit),
         };
     }
 
     get max409Retries(): number {
-        return this.ini["max_409_retries"] ?? 3;
+        return parseInt((this.ini["max_409_retries"] ?? "3") as string);
     }
 
     get maxUploadSize(): number {
-        return this.ini?.["upload"]?.["sizeLimit"] ?? 200 * 1024 * 1024;
+        // Default to 200MB (1024 * 1024 * 200 = 209715200)
+        return parseInt(((this.ini["upload"] as ConfigRecord | undefined)?.["sizeLimit"] ?? "209715200") as string);
     }
 
     get notifyMethod(): string {
-        return this.ini?.["notify"]?.["method"] ?? "ntfy";
+        return ((this.ini["notify"] as ConfigRecord | undefined)?.["method"] ?? "ntfy") as string;
     }
 
     get ntfyConfig(): Record<string, string> {
         return {
-            defaultChannel: this.ini?.["notify"]?.["ntfy_defaultChannel"] ?? "vudl-ntfy",
+            defaultChannel: ((this.ini["notify"] as ConfigRecord | undefined)?.["ntfy_defaultChannel"] ??
+                "vudl-ntfy") as string,
         };
     }
 
     get indexerLockRetries(): number {
-        return parseInt(this.ini?.["indexer"]?.["lockRetries"] ?? 60);
+        return parseInt(((this.ini["indexer"] as ConfigRecord | undefined)?.["lockRetries"] ?? "60") as string);
     }
 
     get indexerLockWaitMs(): number {
-        return parseInt(this.ini?.["indexer"]?.["lockWaitMs"] ?? 1000);
+        return parseInt(((this.ini["indexer"] as ConfigRecord | undefined)?.["lockWaitMs"] ?? "1000") as string);
     }
 
     get indexerExceptionRetries(): number {
-        return parseInt(this.ini?.["indexer"]?.["exceptionRetries"] ?? 10);
+        return parseInt(((this.ini["indexer"] as ConfigRecord | undefined)?.["exceptionRetries"] ?? "10") as string);
     }
 
     get indexerExceptionWaitMs(): number {
-        return parseInt(this.ini?.["indexer"]?.["exceptionWaitMs"] ?? 500);
+        return parseInt(((this.ini["indexer"] as ConfigRecord | undefined)?.["exceptionWaitMs"] ?? "500") as string);
     }
 }
 
diff --git a/api/src/models/FedoraDataCollection.test.ts b/api/src/models/FedoraDataCollection.test.ts
index 55c107f4..d88ab26d 100644
--- a/api/src/models/FedoraDataCollection.test.ts
+++ b/api/src/models/FedoraDataCollection.test.ts
@@ -1,7 +1,7 @@
 import Config from "./Config";
 import FedoraDataCollection from "./FedoraDataCollection";
 
-let fedoraData;
+let fedoraData: FedoraDataCollection;
 beforeEach(() => {
     Config.setInstance(new Config({}));
     fedoraData = FedoraDataCollection.build("foo:123");
diff --git a/api/src/models/FedoraDataCollection.ts b/api/src/models/FedoraDataCollection.ts
index b02e4357..d288f20d 100644
--- a/api/src/models/FedoraDataCollection.ts
+++ b/api/src/models/FedoraDataCollection.ts
@@ -42,10 +42,10 @@ class FedoraDataCollection {
         metadata: Record<string, Array<string>> = {},
         fedoraDetails: Record<string, Array<string>> = {},
         fedoraDatastreams: Array<string> = [],
-        fedora: Fedora = null,
-        extractor: MetadataExtractor = null,
-        tika: TikaExtractor = null,
-        config: Config = null,
+        fedora: Fedora | null = null,
+        extractor: MetadataExtractor | null = null,
+        tika: TikaExtractor | null = null,
+        config: Config | null = null,
     ): FedoraDataCollection {
         return new FedoraDataCollection(
             pid,
@@ -91,7 +91,7 @@ class FedoraDataCollection {
      * Create a flattened list of all PIDs "above" the current one.
      */
     getAllParents(): Array<string> {
-        const results = [];
+        const results: Array<string> = [];
         this.parents.forEach((parent) => {
             const parentPids = [parent.pid].concat(parent.getAllParents());
             parentPids.forEach((pid) => {
@@ -116,7 +116,7 @@ class FedoraDataCollection {
         };
     }
 
-    async getThumbnailHash(type: string): Promise<string> {
+    async getThumbnailHash(type: string): Promise<string | null> {
         const hashes = (await this.datastreamDetails.getThumbnails()).hasMessageDigest ?? [];
         for (const hash of hashes) {
             const parts = hash.split(":");
@@ -132,7 +132,7 @@ class FedoraDataCollection {
         return fitsData[name] ?? [];
     }
 
-    async getFitsValueAsString(name: string): Promise<string> {
+    async getFitsValueAsString(name: string): Promise<string | null> {
         const fitsData = await this.datastreamDetails.getFitsData();
         if (typeof fitsData[name] === "undefined") {
             return null;
@@ -140,12 +140,12 @@ class FedoraDataCollection {
         return fitsData[name][0] ?? null;
     }
 
-    async getFileSize(): Promise<string> {
+    async getFileSize(): Promise<string | null> {
         return await this.getFitsValueAsString("size");
     }
 
     async getFullText(): Promise<Array<string>> {
-        let fullText = [];
+        let fullText: Array<string> = [];
         const rawFullText = await this.datastreamDetails.getFullText();
         for (const current in rawFullText) {
             fullText = fullText.concat(rawFullText[current]);
@@ -156,11 +156,11 @@ class FedoraDataCollection {
         });
     }
 
-    async getImageHeight(): Promise<string> {
+    async getImageHeight(): Promise<string | null> {
         return await this.getFitsValueAsString("imageHeight");
     }
 
-    async getImageWidth(): Promise<string> {
+    async getImageWidth(): Promise<string | null> {
         return await this.getFitsValueAsString("imageWidth");
     }
 
@@ -176,7 +176,7 @@ class FedoraDataCollection {
     get models(): Array<string> {
         // Separate identifier from URI prefix
         return (this.fedoraDetails.hasModel ?? []).map((model) => {
-            return model.split("/").pop();
+            return model.split("/").pop() as string;
         });
     }
 
diff --git a/api/src/models/ImageFile.ts b/api/src/models/ImageFile.ts
index a916e1a0..c05fe992 100644
--- a/api/src/models/ImageFile.ts
+++ b/api/src/models/ImageFile.ts
@@ -1,10 +1,7 @@
 import sharp from "sharp";
 import path = require("path");
-
 import { execSync } from "child_process";
-
 import Config from "./Config";
-
 import fs = require("fs");
 
 class ImageFile {
diff --git a/api/src/models/Job.ts b/api/src/models/Job.ts
index 2d3ea81b..9f4df828 100644
--- a/api/src/models/Job.ts
+++ b/api/src/models/Job.ts
@@ -1,5 +1,7 @@
+/// <reference path="../types/pdfkit-augment.d.ts" />
 import { createWriteStream, openSync, closeSync, existsSync as fileExists, statSync } from "fs";
 import PDFDocument = require("pdfkit");
+
 import path = require("path");
 
 import Config from "./Config";
@@ -11,7 +13,7 @@ import QueueManager from "../services/QueueManager";
 class Job {
     dir: string;
     name: string;
-    _metadata: JobMetadata = null;
+    _metadata: JobMetadata | null = null;
     config: Config;
     queue: QueueManager;
 
@@ -71,7 +73,7 @@ class Job {
 
     protected async getLargeJpegs(): Promise<Array<string>> {
         const pages = this.metadata.order.pages;
-        const jpegs = [];
+        const jpegs: string[] = [];
         for (const i in pages) {
             const image = ImageFile.build(this.dir + "/" + pages[i].filename);
             jpegs[i] = await image.derivative("LARGE");
diff --git a/api/src/models/JobMetadata.ts b/api/src/models/JobMetadata.ts
index 698405b6..c8cf8b4f 100644
--- a/api/src/models/JobMetadata.ts
+++ b/api/src/models/JobMetadata.ts
@@ -16,12 +16,12 @@ interface JobMetadataRaw {
 
 class JobMetadata {
     job: Job;
-    page: PageRaw;
+    page: PageRaw | null = null;
     _filename: string;
-    _order: PageOrder = null;
-    _documents: DocumentOrder = null;
-    _audio: AudioOrder = null;
-    _video: VideoOrder = null;
+    _order: PageOrder | null = null;
+    _documents: DocumentOrder | null = null;
+    _audio: AudioOrder | null = null;
+    _video: VideoOrder | null = null;
     published = false;
 
     constructor(job: Job) {
@@ -58,7 +58,7 @@ class JobMetadata {
         return this.job.dir + "/derivatives.lock";
     }
 
-    get derivativeStatus(): Record<string, unknown> {
+    get derivativeStatus(): { expected: number; processed: number; building: boolean } {
         const lockfileExists: boolean = fs.existsSync(this.derivativeLockfile);
         const status = {
             expected: 0,
@@ -121,7 +121,9 @@ class JobMetadata {
 
     get ingestInfo(): string {
         const logfile: string = this.job.dir + "/ingest.log";
-        return fs.existsSync(logfile) ? fs.readFileSync(logfile, "utf-8").split("\n").filter(Boolean).pop() : "";
+        return fs.existsSync(logfile)
+            ? (fs.readFileSync(logfile, "utf-8").split("\n").filter(Boolean).pop() ?? "")
+            : "";
     }
 
     get order(): PageOrder {
diff --git a/api/src/models/PageOrder.ts b/api/src/models/PageOrder.ts
index 3f199273..9fc1bde3 100644
--- a/api/src/models/PageOrder.ts
+++ b/api/src/models/PageOrder.ts
@@ -30,7 +30,7 @@ class PageOrder {
             return firstPartResults === 0 ? a.localeCompare(b) : firstPartResults;
         });
         const pages = files.map((file) => {
-            return new Page(path.basename(file), null);
+            return new Page(path.basename(file), "");
         });
         return new PageOrder(pages);
     }
diff --git a/api/src/models/VideoFile.ts b/api/src/models/VideoFile.ts
index 713116d4..9bc12b3d 100644
--- a/api/src/models/VideoFile.ts
+++ b/api/src/models/VideoFile.ts
@@ -9,7 +9,7 @@ class VideoFile extends AbstractAVFile {
         return new VideoFile(filename, dir, Config.getInstance());
     }
 
-    static fromRaw(raw: Record<string, string>, config: Config = null): VideoFile {
+    static fromRaw(raw: Record<string, string>, config: Config | null = null): VideoFile {
         return new VideoFile(raw.filename, raw.label, config ?? Config.getInstance());
     }
 
diff --git a/api/src/routes/auth.test.ts b/api/src/routes/auth.test.ts
index 6890ce9a..31457428 100644
--- a/api/src/routes/auth.test.ts
+++ b/api/src/routes/auth.test.ts
@@ -1,5 +1,5 @@
-import * as request from "supertest";
-import * as session from "express-session";
+import request from "supertest";
+import session from "express-session";
 import { StatusCodes } from "http-status-codes";
 import app from "../app";
 import { getAuthRouter } from "./auth";
diff --git a/api/src/routes/edit.test.ts b/api/src/routes/edit.test.ts
index a67617fd..f8e28d30 100644
--- a/api/src/routes/edit.test.ts
+++ b/api/src/routes/edit.test.ts
@@ -1,4 +1,4 @@
-import * as request from "supertest";
+import request from "supertest";
 import { StatusCodes } from "http-status-codes";
 import app from "../app";
 import edit from "./edit";
diff --git a/api/src/routes/index.test.ts b/api/src/routes/index.test.ts
index 9b2ba0bf..a848f2c0 100644
--- a/api/src/routes/index.test.ts
+++ b/api/src/routes/index.test.ts
@@ -1,4 +1,4 @@
-import * as request from "supertest";
+import request from "supertest";
 import { StatusCodes } from "http-status-codes";
 import app from "../app";
 import index from "./index";
diff --git a/api/src/routes/messenger.test.ts b/api/src/routes/messenger.test.ts
index 819bec02..1939b1fc 100644
--- a/api/src/routes/messenger.test.ts
+++ b/api/src/routes/messenger.test.ts
@@ -1,4 +1,4 @@
-import * as request from "supertest";
+import request from "supertest";
 import { StatusCodes } from "http-status-codes";
 import app from "../app";
 import messenger from "./messenger";
diff --git a/api/src/server.ts b/api/src/server.ts
index b9ccab46..3567b51b 100644
--- a/api/src/server.ts
+++ b/api/src/server.ts
@@ -2,9 +2,9 @@
  * Module dependencies.
  */
 
-import * as http from "http";
-import * as passport from "passport";
-import * as session from "express-session";
+import http from "http";
+import passport from "passport";
+import session from "express-session";
 import debug from "debug";
 
 import app from "./app";
diff --git a/api/src/services/JobQueue.test.ts b/api/src/services/JobQueue.test.ts
index 5531bb9c..28f737f9 100644
--- a/api/src/services/JobQueue.test.ts
+++ b/api/src/services/JobQueue.test.ts
@@ -5,19 +5,19 @@ const mockDerivative = {
     run: jest.fn(),
 };
 jest.mock("../jobs/Derivative", () => {
-    return { default: jest.fn().mockImplementation(() => mockDerivative) };
+    return { __esModule: true, default: jest.fn().mockImplementation(() => mockDerivative) };
 });
 jest.mock("../jobs/GeneratePdf", () => {
-    return { default: jest.fn() };
+    return { __esModule: true, default: jest.fn() };
 });
 jest.mock("../jobs/Index", () => {
-    return { default: jest.fn() };
+    return { __esModule: true, default: jest.fn() };
 });
 jest.mock("../jobs/Ingest", () => {
-    return { default: jest.fn() };
+    return { __esModule: true, default: jest.fn() };
 });
 jest.mock("../jobs/Metadata", () => {
-    return { default: jest.fn() };
+    return { __esModule: true, default: jest.fn() };
 });
 
 describe("JobQueue", () => {
diff --git a/api/src/services/QueueManager.ts b/api/src/services/QueueManager.ts
index 1b8d52b5..501a0e94 100644
--- a/api/src/services/QueueManager.ts
+++ b/api/src/services/QueueManager.ts
@@ -29,14 +29,14 @@ class QueueManager {
         };
     }
 
-    protected getQueue(queueName: string = null): Queue {
-        return new Queue(queueName ?? this.config.redisDefaultQueueName, this.queueBaseOptions);
+    protected getQueue(queueName: string = ""): Queue {
+        return new Queue(queueName || this.config.redisDefaultQueueName, this.queueBaseOptions);
     }
 
-    public getWorker(callback: Processor, queueName: string = null): Worker {
+    public getWorker(callback: Processor, queueName: string = ""): Worker {
         const options: WorkerOptions = this.queueBaseOptions;
         options.lockDuration = this.config.redisLockDuration;
-        return new Worker(queueName ?? this.config.redisDefaultQueueName, callback, options);
+        return new Worker(queueName || this.config.redisDefaultQueueName, callback, options);
     }
 
     protected getQueueNameForJob(jobName: string): string {
@@ -61,7 +61,7 @@ class QueueManager {
         return await this.addToQueue("ingest", { dir });
     }
 
-    public async sendNotification(body: string, channel: string | null = null): Promise<void> {
+    public async sendNotification(body: string, channel: string = ""): Promise<void> {
         return await this.addToQueue("notify", { body, channel });
     }
 
@@ -69,7 +69,7 @@ class QueueManager {
         return await this.addToQueue("reindex", { file });
     }
 
-    public async hasPendingIndexJob(q, queueJob): Promise<boolean> {
+    public async hasPendingIndexJob(q: Queue, queueJob: { pid: string; action: string }): Promise<boolean> {
         if (this.cache.isEnabled()) {
             return this.cache.isPidLocked(queueJob.pid, queueJob.action);
         }
diff --git a/api/src/services/Solr.test.ts b/api/src/services/Solr.test.ts
index 26183165..5cd2ee3a 100644
--- a/api/src/services/Solr.test.ts
+++ b/api/src/services/Solr.test.ts
@@ -1,6 +1,6 @@
 import Solr from "./Solr";
 import SolrCache from "./SolrCache";
-import * as fs from "fs";
+import fs from "fs";
 
 describe("Solr", () => {
     let solr;
diff --git a/api/src/services/SolrCache.test.ts b/api/src/services/SolrCache.test.ts
index 89e465c4..46f80581 100644
--- a/api/src/services/SolrCache.test.ts
+++ b/api/src/services/SolrCache.test.ts
@@ -1,5 +1,5 @@
 import { SolrAddDoc, SolrCache } from "./SolrCache";
-import * as fs from "fs";
+import fs from "fs";
 import glob = require("glob");
 
 describe("SolrCache", () => {
diff --git a/api/src/services/SolrCache.ts b/api/src/services/SolrCache.ts
index dff41620..2ecbbeca 100644
--- a/api/src/services/SolrCache.ts
+++ b/api/src/services/SolrCache.ts
@@ -159,7 +159,7 @@ export class SolrCache {
         }
 
         let document: Array<object> = [];
-        let currentBatch: { file: string; size: number } = { file: null, size: 0 };
+        let currentBatch: { file: string; size: number } = { file: "", size: 0 };
         docs.forEach((file) => {
             const nextObject = this.readSolrAddDocFromFile(file);
             if (nextObject?.add?.doc === undefined) {
@@ -167,7 +167,7 @@ export class SolrCache {
                 return;
             }
             document.push(nextObject.add.doc);
-            if (currentBatch.file === null) {
+            if (currentBatch.file === "") {
                 currentBatch.file = file.replace(new RegExp("^" + this.cacheDir), targetDir);
                 console.log(`Starting batch ${currentBatch.file}`);
             }
@@ -175,7 +175,7 @@ export class SolrCache {
             if (currentBatch.size == batchSize) {
                 this.writeFile(currentBatch.file, JSON.stringify(document));
                 document = [];
-                currentBatch = { file: null, size: 0 };
+                currentBatch = { file: "", size: 0 };
             }
         });
         if (currentBatch.size > 0) {
diff --git a/api/src/types/pdfkit-augment.d.ts b/api/src/types/pdfkit-augment.d.ts
new file mode 100644
index 00000000..a25f4124
--- /dev/null
+++ b/api/src/types/pdfkit-augment.d.ts
@@ -0,0 +1,15 @@
+// Work around for a flaw in @types/pdfkit, which omits `openImage()` from the type definitions.
+// even though pdfkit implements and exports it (lib/mixins/images.js).
+
+declare namespace PDFKit.Mixins {
+    interface OpenedImage {
+        width: number;
+        height: number;
+    }
+
+    interface PDFImage {
+        openImage(src: string | Buffer): OpenedImage;
+        image(src: OpenedImage, x?: number, y?: number, options?: ImageOption): this;
+        image(src: OpenedImage, options?: ImageOption): this;
+    }
+}
diff --git a/api/tsconfig.json b/api/tsconfig.json
index 0d5405de..c1c4c64c 100644
--- a/api/tsconfig.json
+++ b/api/tsconfig.json
@@ -2,9 +2,13 @@
     "compilerOptions": {
       "sourceMap": true,
       "allowJs": true,
-      "target": "es5",
+      "target": "es2022",
+      "module": "commonjs",
+      "strict": false,
       "outDir": "./dist",
-      "skipLibCheck": true
+      "skipLibCheck": true,
+      "esModuleInterop": true,
+      "types": ["jest"]
     },
     "include": [
       "./src/**/*"