diff --git a/lib/FredyRuntime.js b/lib/FredyRuntime.js
index 29f54f2..0d9b50c 100755
--- a/lib/FredyRuntime.js
+++ b/lib/FredyRuntime.js
@@ -5,14 +5,54 @@ import Extractor from './services/extractor/extractor.js';
 import urlModifier from './services/queryStringMutator.js';
 import logger from './services/logger.js';
 
+/**
+ * @typedef {Object} Listing
+ * @property {string} id Stable unique identifier (hash) of the listing.
+ * @property {string} title Title or headline of the listing.
+ * @property {string} [address] Optional address/location text.
+ * @property {string} [price] Optional price text/value.
+ * @property {string} [url] Link to the listing detail page.
+ * @property {any} [meta] Provider-specific additional metadata.
+ */
+
+/**
+ * @typedef {Object} SimilarityCache
+ * @property {(title:string, address?:string)=>boolean} hasSimilarEntries Returns true if a similar entry is known.
+ * @property {(title:string, address?:string)=>void} addCacheEntry Adds a new entry to the similarity cache.
+ */
+
+/**
+ * Runtime orchestrator for fetching, normalizing, filtering, deduplicating, storing,
+ * and notifying about new listings from a configured provider.
+ *
+ * The execution flow is:
+ * 1) Prepare provider URL (sorting, etc.)
+ * 2) Extract raw listings from the provider
+ * 3) Normalize listings to the provider schema
+ * 4) Filter out incomplete/blacklisted listings
+ * 5) Identify new listings (vs. previously stored hashes)
+ * 6) Persist new listings
+ * 7) Filter out entries similar to already seen ones
+ * 8) Dispatch notifications
+ */
 class FredyRuntime {
   /**
+   * Create a new runtime instance for a single provider/job execution.
    *
-   * @param providerConfig the config for the specific provider, we're going to query at the moment
-   * @param notificationConfig the config for all notifications
-   * @param providerId the id of the provider currently in use
-   * @param jobKey key of the job that is currently running (from within the config)
-   * @param similarityCache cache instance holding values to check for similarity of entries
+   * @param {Object} providerConfig Provider configuration.
+   * @param {string} providerConfig.url Base URL to crawl.
+   * @param {string} [providerConfig.sortByDateParam] Query parameter used to enforce sorting by date (provider-specific).
+   * @param {string} [providerConfig.waitForSelector] CSS selector to wait for before parsing content.
+   * @param {Object.<string, string>} providerConfig.crawlFields Mapping of field names to selectors/paths to extract.
+   * @param {string} providerConfig.crawlContainer CSS selector for the container holding listing items.
+   * @param {(raw:any)=>Listing} providerConfig.normalize Function to convert raw scraped data into a Listing shape.
+   * @param {(listing:Listing)=>boolean} providerConfig.filter Function to filter out unwanted listings.
+   * @param {(url:string, waitForSelector?:string)=>Promise<void>|Promise<Listing[]>} [providerConfig.getListings] Optional override to fetch listings.
+   *
+   * @param {Object} notificationConfig Notification configuration passed to notification adapters.
+   * @param {string} providerId The ID of the provider currently in use.
+   * @param {string} jobKey Key of the job that is currently running (from within the config).
+   * @param {SimilarityCache} similarityCache Cache instance for checking similar entries.
    */
   constructor(providerConfig, notificationConfig, providerId, jobKey, similarityCache) {
     this._providerConfig = providerConfig;
@@ -22,29 +62,31 @@ class FredyRuntime {
     this._similarityCache = similarityCache;
   }
 
+  /**
+   * Execute the end-to-end pipeline for a single provider run.
+   *
+   * @returns {Promise<Listing[]|void>} Resolves to the list of new (and similarity-filtered) listings
+   * after notifications have been sent; resolves to void when there are no new listings.
+   */
   execute() {
-    return (
-      //modify the url to make sure search order is correctly set
-      Promise.resolve(urlModifier(this._providerConfig.url, this._providerConfig.sortByDateParam))
-        //scraping the site and try finding new listings
-        .then(this._providerConfig.getListings?.bind(this) ?? this._getListings.bind(this))
-        //bring them in a proper form (dictated by the provider)
-        .then(this._normalize.bind(this))
-        //filter listings with stuff tagged by the blacklist of the provider
-        .then(this._filter.bind(this))
-        //check if new listings available. if so proceed
-        .then(this._findNew.bind(this))
-        //store everything in db
-        .then(this._save.bind(this))
-        //check for similar listings. if found, remove them before notifying
-        .then(this._filterBySimilarListings.bind(this))
-        //notify the user using the configured notification adapter
-        .then(this._notify.bind(this))
-        //if an error occurred on the way, handle it here.
-        .catch(this._handleError.bind(this))
-    );
+    return Promise.resolve(urlModifier(this._providerConfig.url, this._providerConfig.sortByDateParam))
+      .then(this._providerConfig.getListings?.bind(this) ?? this._getListings.bind(this))
+      .then(this._normalize.bind(this))
+      .then(this._filter.bind(this))
+      .then(this._findNew.bind(this))
+      .then(this._save.bind(this))
+      .then(this._filterBySimilarListings.bind(this))
+      .then(this._notify.bind(this))
+      .catch(this._handleError.bind(this));
   }
 
+  /**
+   * Fetch listings from the provider, using the default Extractor flow unless
+   * a provider-specific getListings override is supplied.
+   *
+   * @param {string} url The provider URL to fetch from.
+   * @returns {Promise<Listing[]>} Resolves with an array of listings (empty when none found).
+   */
   _getListings(url) {
     const extractor = new Extractor();
     return new Promise((resolve, reject) => {
@@ -65,17 +107,36 @@ class FredyRuntime {
     });
   }
 
+  /**
+   * Normalize raw listings into the provider-specific Listing shape.
+   *
+   * @param {any[]} listings Raw listing entries from the extractor or override.
+   * @returns {Listing[]} Normalized listings.
+   */
   _normalize(listings) {
     return listings.map(this._providerConfig.normalize);
   }
 
+  /**
+   * Filter out listings that are missing required fields and those rejected by the
+   * provider's blacklist/filter function.
+   *
+   * @param {Listing[]} listings Listings to filter.
+   * @returns {Listing[]} Filtered listings that pass validation and provider filter.
+   */
   _filter(listings) {
-    //only return those where all the fields have been found
     const keys = Object.keys(this._providerConfig.crawlFields);
     const filteredListings = listings.filter((item) => keys.every((key) => key in item));
     return filteredListings.filter(this._providerConfig.filter);
   }
 
+  /**
+   * Determine which listings are new by comparing their IDs against stored hashes.
+   *
+   * @param {Listing[]} listings Listings to evaluate for novelty.
+   * @returns {Listing[]} New listings not seen before.
+   * @throws {NoNewListingsWarning} When no new listings are found.
+   */
   _findNew(listings) {
     logger.debug(`Checking ${listings.length} listings for new entries (Provider: '${this._providerId}')`);
     const hashes = getKnownListingHashesForJobAndProvider(this._jobKey, this._providerId) || [];
@@ -87,6 +148,13 @@ class FredyRuntime {
     return newListings;
   }
 
+  /**
+   * Send notifications for new listings using the configured notification adapter(s).
+   *
+   * @param {Listing[]} newListings New listings to notify about.
+   * @returns {Promise<Listing[]>} Resolves to the provided listings after notifications complete.
+   * @throws {NoNewListingsWarning} When there are no listings to notify about.
+   */
   _notify(newListings) {
     if (newListings.length === 0) {
       throw new NoNewListingsWarning();
@@ -95,12 +163,25 @@ class FredyRuntime {
     return Promise.all(sendNotifications).then(() => newListings);
   }
 
+  /**
+   * Persist new listings and pass them through.
+   *
+   * @param {Listing[]} newListings Listings to store.
+   * @returns {Listing[]} The same listings, unchanged.
+   */
   _save(newListings) {
     logger.debug(`Storing ${newListings.length} new listings (Provider: '${this._providerId}')`);
     storeListings(this._jobKey, this._providerId, newListings);
     return newListings;
   }
 
+  /**
+   * Remove listings that are similar to already known entries according to the similarity cache.
+   * Adds the remaining listings to the cache.
+   *
+   * @param {Listing[]} listings Listings to filter by similarity.
+   * @returns {Listing[]} Listings considered unique enough to keep.
+   */
   _filterBySimilarListings(listings) {
     const filteredList = listings.filter((listing) => {
       const similar = this._similarityCache.hasSimilarEntries(listing.title, listing.address);
@@ -115,6 +196,12 @@ class FredyRuntime {
     return filteredList;
   }
 
+  /**
+   * Handle errors occurring in the pipeline, logging levels depending on type.
+   *
+   * @param {Error} err Error instance thrown by previous steps.
+   * @returns {void}
+   */
   _handleError(err) {
     if (err.name === 'NoNewListingsWarning') {
       logger.debug(`No new listings found (Provider: '${this._providerId}').`);
diff --git a/lib/services/storage/migrations/sql/5.job-sharing.js b/lib/services/storage/migrations/sql/5.job-sharing.js
index 2a581ff..7b6e16d 100644
--- a/lib/services/storage/migrations/sql/5.job-sharing.js
+++ b/lib/services/storage/migrations/sql/5.job-sharing.js
@@ -1,4 +1,4 @@
-// Migration: Adding a new table to store if somebody "watches" (a.k.a favorite) a listing
+// Migration: Adding a new table to store if somebody shared a job with someone
 
 export function up(db) {
   db.exec(`