diff --git a/Cargo.lock b/Cargo.lock
index 72a0cf1..bd4244a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -417,6 +417,7 @@ dependencies = [
  "futures",
  "reqwest",
  "serde",
+ "serde_json",
  "tokio",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index 45494ab..6162361 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,3 +10,4 @@ serde = { version = "1.0.123", features = ["derive"] }
 anyhow = "1.0.38"
 tokio = { version = "0.2.25", features = ["full"] }
 futures = "0.3.13"
+serde_json = "1.0.64"
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..8ae8f3f
--- /dev/null
+++ b/README.md
@@ -0,0 +1,15 @@
+# Lemmy-Stats-Crawler
+
+Crawls Lemmy instances using nodeinfo and API endpoints, to generate a list of instances and overall details.
+
+## Usage
+
+For testing:
+```
+cargo run
+```
+
+For production (hide debug logs):
+```
+cargo run 2>/dev/null
+```
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index c79cabe..10ce7c4 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,6 +1,7 @@
 use anyhow::Error;
 use lemmy_stats_crawler::federated_instances::GetSiteResponse;
 use lemmy_stats_crawler::node_info::NodeInfo;
+use serde::Serialize;
 
 #[derive(Default, Debug)]
 struct TotalStats {
@@ -12,20 +13,22 @@ struct TotalStats {
 pub async fn main() -> Result<(), Error> {
     let mut pending_instances = vec!["lemmy.ml".to_string()];
     let mut crawled_instances = vec![];
+    let mut instance_details = vec![];
     let mut total_stats = TotalStats::default();
     while let Some(pi) = pending_instances.iter().next() {
         crawled_instances.push(pi.to_owned());
-        let instance_details = fetch_instance_details(&pi).await.ok();
+        let current_instance_details = fetch_instance_details(&pi).await.ok();
         pending_instances = pending_instances
             .iter()
             .filter(|i| i != &pi)
             .map(|i| i.to_owned())
             .collect();
 
-        if let Some(details) = instance_details {
+        if let Some(details) = current_instance_details {
+            instance_details.push(details.to_owned());
             total_stats.online_users += details.online_users;
             total_stats.users += details.total_users;
-            // remove all which are in crawled_instances
+            // add all unknown, linked instances to pending
             for ci in details.linked_instances {
                 if !crawled_instances.contains(&ci) {
                     pending_instances.push(ci);
@@ -33,14 +36,26 @@ pub async fn main() -> Result<(), Error> {
             }
         }
     }
+    instance_details = instance_details
+        .iter()
+        .filter(|i| i.open_registrations)
+        .map(|i| i.to_owned())
+        .collect();
+    instance_details.sort_by(|a, b| b.users_active_halfyear.cmp(&a.users_active_halfyear));
+    print!("{}", serde_json::to_string(&instance_details)?);
     dbg!(total_stats);
     Ok(())
 }
 
+#[derive(Serialize, Clone)]
 struct InstanceDetails {
     domain: String,
     online_users: i32,
     total_users: i64,
+    users_active_halfyear: i64,
+    users_active_month: i64,
+    open_registrations: bool,
+    #[serde(skip)]
     linked_instances: Vec<String>,
 }
 
@@ -57,6 +72,9 @@ async fn fetch_instance_details(domain: &str) -> Result<InstanceDetails, Error>
         domain: domain.to_owned(),
         online_users: site_info.online as i32,
         total_users: node_info.usage.users.total,
+        users_active_halfyear: node_info.usage.users.active_halfyear,
+        users_active_month: node_info.usage.users.active_month,
+        open_registrations: node_info.open_registrations,
         linked_instances: site_info
             .federated_instances
             .map(|f| f.linked)