diff --git a/Userland/Libraries/LibWeb/CMakeLists.txt b/Userland/Libraries/LibWeb/CMakeLists.txt
index 16afd614a5e..7e3d2c48fe8 100644
--- a/Userland/Libraries/LibWeb/CMakeLists.txt
+++ b/Userland/Libraries/LibWeb/CMakeLists.txt
@@ -501,6 +501,7 @@ set(SOURCES
     Infra/ByteSequences.cpp
     Infra/JSON.cpp
     Infra/Strings.cpp
+    IndexedDB/Internal/Algorithms.cpp
     IndexedDB/Internal/Database.cpp
     IndexedDB/IDBFactory.cpp
     IndexedDB/IDBOpenDBRequest.cpp
diff --git a/Userland/Libraries/LibWeb/IndexedDB/Internal/Algorithms.cpp b/Userland/Libraries/LibWeb/IndexedDB/Internal/Algorithms.cpp
new file mode 100644
index 00000000000..8973d3345b2
--- /dev/null
+++ b/Userland/Libraries/LibWeb/IndexedDB/Internal/Algorithms.cpp
@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2024, stelar7 <dudedbz@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/VM.h>
+#include <LibWeb/HTML/EventNames.h>
+#include <LibWeb/IndexedDB/IDBRequest.h>
+#include <LibWeb/IndexedDB/Internal/Algorithms.h>
+#include <LibWeb/IndexedDB/Internal/ConnectionQueueHandler.h>
+#include <LibWeb/IndexedDB/Internal/Database.h>
+#include <LibWeb/StorageAPI/StorageKey.h>
+
+namespace Web::IndexedDB {
+
+// https://w3c.github.io/IndexedDB/#open-a-database-connection
+WebIDL::ExceptionOr<JS::NonnullGCPtr<IDBDatabase>> open_a_database_connection(JS::Realm& realm, StorageAPI::StorageKey storage_key, String name, Optional<u64> maybe_version, JS::NonnullGCPtr<IDBRequest> request)
+{
+    // 1. Let queue be the connection queue for storageKey and name.
+    auto& queue = ConnectionQueueHandler::for_key_and_name(storage_key, name);
+
+    // 2. Add request to queue.
+    queue.append(request);
+
+    // 3. Wait until all previous requests in queue have been processed.
+    HTML::main_thread_event_loop().spin_until(JS::create_heap_function(realm.vm().heap(), [queue, request]() {
+        return queue.all_previous_requests_processed(request);
+    }));
+
+    // 4. Let db be the database named name in storageKey, or null otherwise.
+    auto maybe_db = Database::for_key_and_name(storage_key, name);
+    JS::GCPtr<Database> db;
+
+    // 5. If version is undefined, let version be 1 if db is null, or db’s version otherwise.
+    auto version = maybe_version.value_or(maybe_db.has_value() ? maybe_db.value()->version() : 1);
+
+    // 6. If db is null, let db be a new database with name name, version 0 (zero), and with no object stores.
+    // If this fails for any reason, return an appropriate error (e.g. a "QuotaExceededError" or "UnknownError" DOMException).
+    if (!maybe_db.has_value()) {
+        auto maybe_database = Database::create_for_key_and_name(realm, storage_key, name);
+
+        if (maybe_database.is_error()) {
+            return WebIDL::OperationError::create(realm, "Unable to create a new database"_string);
+        }
+
+        db = maybe_database.release_value();
+    }
+
+    // 7. If db’s version is greater than version, return a newly created "VersionError" DOMException and abort these steps.
+    if (db->version() > version) {
+        return WebIDL::VersionError::create(realm, "Database version is greater than the requested version"_string);
+    }
+
+    // 8. Let connection be a new connection to db.
+    auto connection = IDBDatabase::create(realm, *db);
+
+    // 9. Set connection’s version to version.
+    connection->set_version(version);
+
+    // 10. If db’s version is less than version, then:
+    if (db->version() < version) {
+        // 1. Let openConnections be the set of all connections, except connection, associated with db.
+        auto open_connections = db->associated_connections_except(connection);
+
+        // FIXME: 2. For each entry of openConnections that does not have its close pending flag set to true,
+        //    queue a task to fire a version change event named versionchange at entry with db’s version and version.
+        for (auto& entry : open_connections) {
+            if (!entry->close_pending()) {
+            }
+        }
+
+        // FIXME: 3. Wait for all of the events to be fired.
+
+        // FIXME: 4. If any of the connections in openConnections are still not closed,
+        //    queue a task to fire a version change event named blocked at request with db’s version and version.
+        for (auto& entry : open_connections) {
+            if (entry->state() != IDBDatabase::ConnectionState::Closed) {
+            }
+        }
+
+        // 5. Wait until all connections in openConnections are closed.
+        HTML::main_thread_event_loop().spin_until(JS::create_heap_function(realm.vm().heap(), [open_connections]() {
+            for (auto const& entry : open_connections) {
+                if (entry->state() != IDBDatabase::ConnectionState::Closed) {
+                    return false;
+                }
+            }
+
+            return true;
+        }));
+
+        // FIXME: 6. Run upgrade a database using connection, version and request.
+        // NOTE: upgrade a database sets this flag, so we set it manually temporarily.
+        request->set_processed(true);
+
+        // 7. If connection was closed, return a newly created "AbortError" DOMException and abort these steps.
+        if (connection->state() == IDBDatabase::ConnectionState::Closed) {
+            return WebIDL::AbortError::create(realm, "Connection was closed"_string);
+        }
+
+        // FIXME: 8. If the upgrade transaction was aborted, run the steps to close a database connection with connection,
+        // return a newly created "AbortError" DOMException and abort these steps.
+    }
+
+    // 11. Return connection.
+    return connection;
+}
+
+}
diff --git a/Userland/Libraries/LibWeb/IndexedDB/Internal/Algorithms.h b/Userland/Libraries/LibWeb/IndexedDB/Internal/Algorithms.h
new file mode 100644
index 00000000000..721cd1a1f7a
--- /dev/null
+++ b/Userland/Libraries/LibWeb/IndexedDB/Internal/Algorithms.h
@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2024, stelar7 <dudedbz@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibJS/Runtime/Realm.h>
+#include <LibWeb/IndexedDB/IDBRequest.h>
+#include <LibWeb/StorageAPI/StorageKey.h>
+
+namespace Web::IndexedDB {
+
+WebIDL::ExceptionOr<JS::NonnullGCPtr<IDBDatabase>> open_a_database_connection(JS::Realm&, StorageAPI::StorageKey, String, Optional<u64>, JS::NonnullGCPtr<IDBRequest>);
+
+}
diff --git a/Userland/Libraries/LibWeb/IndexedDB/Internal/ConnectionQueueHandler.h b/Userland/Libraries/LibWeb/IndexedDB/Internal/ConnectionQueueHandler.h
index 76f2caf6ea5..9a4bd9ff9f1 100644
--- a/Userland/Libraries/LibWeb/IndexedDB/Internal/ConnectionQueueHandler.h
+++ b/Userland/Libraries/LibWeb/IndexedDB/Internal/ConnectionQueueHandler.h
@@ -14,7 +14,21 @@
 
 namespace Web::IndexedDB {
 
-using ConnectionQueue = AK::Vector<JS::Handle<IDBRequest>>;
+class ConnectionQueue : public AK::Vector<JS::Handle<IDBRequest>> {
+public:
+    bool all_previous_requests_processed(JS::NonnullGCPtr<IDBRequest> const& request) const
+    {
+        for (auto const& entry : *this) {
+            if (entry == request)
+                return true;
+            if (!entry->processed())
+                return false;
+        }
+
+        return true;
+    }
+};
+
 using ConnectionMap = HashMap<StorageAPI::StorageKey, HashMap<String, ConnectionQueue>>;
 
 // https://w3c.github.io/IndexedDB/#connection-queues