diff --git a/src/updatechecker.cpp b/src/updatechecker.cpp
new file mode 100644
--- /dev/null
+++ b/src/updatechecker.cpp
@@ -0,0 +1,107 @@
+#include "updatechecker.h"
+#include <QtDebug>
+#include <QJsonDocument>
+#include <QJsonObject>
+#include <QJsonArray>
+#include <QJsonValue>
+
+// This returns the list of downloads in JSON format. Note that we only use the first
+// page because results are sorted in new to old.
+const char BB_DOWNLOADS_URL[] = "https://api.bitbucket.org/2.0/repositories/hyozd/serialplot/downloads?fields=values.name,values.links.self.href";
+
+UpdateChecker::UpdateChecker(QObject *parent) :
+    QObject(parent), nam(this)
+{
+    connect(&nam, &QNetworkAccessManager::finished,
+            this, &UpdateChecker::onReqFinished);
+}
+
+void UpdateChecker::checkUpdate()
+{
+    auto req = QNetworkRequest(QUrl(BB_DOWNLOADS_URL));
+    nam.get(req);
+}
+
+void UpdateChecker::onReqFinished(QNetworkReply* reply)
+{
+    qDebug() << "finished";
+    if (reply->error() != QNetworkReply::NoError)
+    {
+        emit checkFailed(QString("Network error: ") + reply->errorString());
+    }
+    else
+    {
+        QJsonParseError error;
+        auto data = QJsonDocument::fromJson(reply->readAll(), &error);
+        if (error.error != QJsonParseError::NoError)
+        {
+            emit checkFailed(QString("JSon parsing error: ") + error.errorString());
+        }
+        else
+        {
+            QList<FileInfo> files;
+            if (!parseData(data, files))
+            {
+                // TODO: emit detailed data contents for logging
+                emit checkFailed("Data parsing error.");
+                qDebug() << "Data parsing error.";
+            }
+            else
+            {
+                for (auto f : files)
+                {
+                    qDebug() << f.name << f.link;
+                }
+            }
+        }
+    }
+    reply->deleteLater();
+}
+
+bool UpdateChecker::parseData(const QJsonDocument& data, QList<FileInfo>& files)
+{
+    /* Data is expected to be in this form:
+
+    {
+       "values": [
+       {
+         "name": "serialplot-0.9.1-x86_64.AppImage",
+         "links": {
+           "self": {
+             "href": "https://api.bitbucket.org/2.0/repositories/hyOzd/serialplot/downloads/serialplot-0.9.1-x86_64.AppImage"
+            }
+          }
+       }, ... ]
+    }
+    */
+
+    if (!data.isObject()) return false;
+
+    auto values = data.object()["values"];
+    if (values == QJsonValue::Undefined || !values.isArray()) return false;
+
+    for (auto value : values.toArray())
+    {
+        if (!value.isObject()) return false;
+
+        auto name = value.toObject().value("name");
+        if (name.isUndefined() || !name.isString())
+             return false;
+
+        auto links = value.toObject().value("links");
+        if (links.isUndefined() || !links.isObject())
+            return false;
+
+        auto self = links.toObject().value("self");
+        if (self.isUndefined() || !self.isObject())
+            return false;
+
+        auto href = self.toObject().value("href");
+        if (href.isUndefined() || !href.isString())
+            return false;
+
+        files += {name.toString(), href.toString()};
+    }
+
+    return true;
+}