diff --git a/processor/src/coins/monero.rs b/processor/src/coins/monero.rs
index c0cb416a..da5d6ac4 100644
--- a/processor/src/coins/monero.rs
+++ b/processor/src/coins/monero.rs
@@ -24,10 +24,10 @@ impl OutputTrait for Output {
   // While we could use (tx, o), using the key ensures we won't be susceptible to the burning bug.
   // While the Monero library offers a variant which allows senders to ensure their TXs have unique
   // output keys, Serai can still be targeted using the classic burning bug
-  type Id = CompressedEdwardsY;
+  type Id = [u8; 32];
 
   fn id(&self) -> Self::Id {
-    self.0.key.compress()
+    self.0.key.compress().to_bytes()
   }
 
   fn amount(&self) -> u64 {
diff --git a/processor/src/lib.rs b/processor/src/lib.rs
index 3e01dd54..9357bd06 100644
--- a/processor/src/lib.rs
+++ b/processor/src/lib.rs
@@ -13,7 +13,7 @@ mod wallet;
 mod tests;
 
 pub trait Output: Sized + Clone {
-  type Id;
+  type Id: AsRef<[u8]>;
 
   fn id(&self) -> Self::Id;
   fn amount(&self) -> u64;
diff --git a/processor/src/tests/mod.rs b/processor/src/tests/mod.rs
index 1bddc91a..02c8180d 100644
--- a/processor/src/tests/mod.rs
+++ b/processor/src/tests/mod.rs
@@ -2,14 +2,14 @@ use std::rc::Rc;
 
 use rand::rngs::OsRng;
 
-use crate::{Coin, coins::monero::Monero, wallet::{WalletKeys, Wallet}};
+use crate::{Coin, coins::monero::Monero, wallet::{WalletKeys, MemCoinDb, Wallet}};
 
 #[tokio::test]
 async fn test() {
   let monero = Monero::new("http://127.0.0.1:18081".to_string());
   println!("{}", monero.get_height().await.unwrap());
   let mut keys = frost::tests::key_gen::<_, <Monero as Coin>::Curve>(&mut OsRng);
-  let mut wallet = Wallet::new(monero);
+  let mut wallet = Wallet::new(MemCoinDb::new(), monero);
   wallet.acknowledge_height(0, 0);
   wallet.add_keys(&WalletKeys::new(Rc::try_unwrap(keys.remove(&1).take().unwrap()).unwrap(), 0));
   dbg!(0);
diff --git a/processor/src/wallet.rs b/processor/src/wallet.rs
index db05a6cd..0c5b66a9 100644
--- a/processor/src/wallet.rs
+++ b/processor/src/wallet.rs
@@ -33,28 +33,83 @@ impl<C: Curve> WalletKeys<C> {
   }
 }
 
-pub struct CoinDb {
+pub trait CoinDb {
+  // Set a height as scanned to
+  fn scanned_to_height(&mut self, height: usize);
+  // Acknowledge a given coin height for a canonical height
+  fn acknowledge_height(&mut self, canonical: usize, height: usize);
+
+  // Adds an output to the DB. Returns false if the output was already added
+  fn add_output<O: Output>(&mut self, output: &O) -> bool;
+
+  // Height this coin has been scanned to
+  fn scanned_height(&self) -> usize;
+  // Acknowledged height for a given canonical height
+  fn acknowledged_height(&self, canonical: usize) -> usize;
+}
+
+pub struct MemCoinDb {
   // Height this coin has been scanned to
   scanned_height: usize,
   // Acknowledged height for a given canonical height
-  acknowledged_heights: HashMap<usize, usize>
+  acknowledged_heights: HashMap<usize, usize>,
+  outputs: HashMap<Vec<u8>, Vec<u8>>
 }
 
-pub struct Wallet<C: Coin> {
-  db: CoinDb,
+
+impl MemCoinDb {
+  pub fn new() -> MemCoinDb {
+    MemCoinDb {
+      scanned_height: 0,
+      acknowledged_heights: HashMap::new(),
+      outputs: HashMap::new()
+    }
+  }
+}
+
+impl CoinDb for MemCoinDb {
+  fn scanned_to_height(&mut self, height: usize) {
+    self.scanned_height = height;
+  }
+
+  fn acknowledge_height(&mut self, canonical: usize, height: usize) {
+    debug_assert!(!self.acknowledged_heights.contains_key(&canonical));
+    self.acknowledged_heights.insert(canonical, height);
+  }
+
+  fn add_output<O: Output>(&mut self, output: &O) -> bool {
+    // This would be insecure as we're indexing by ID and this will replace the output as a whole
+    // Multiple outputs may have the same ID in edge cases such as Monero, where outputs are ID'd
+    // by key image, not by hash + index
+    // self.outputs.insert(output.id(), output).is_some()
+    let id = output.id().as_ref().to_vec();
+    if self.outputs.contains_key(&id) {
+      return false;
+    }
+    self.outputs.insert(id, output.serialize());
+    true
+  }
+
+  fn scanned_height(&self) -> usize {
+    self.scanned_height
+  }
+
+  fn acknowledged_height(&self, canonical: usize) -> usize {
+    self.acknowledged_heights[&canonical]
+  }
+}
+
+pub struct Wallet<D: CoinDb, C: Coin> {
+  db: D,
   coin: C,
   keys: Vec<(Arc<MultisigKeys<C::Curve>>, Vec<C::Output>)>,
   pending: Vec<(usize, MultisigKeys<C::Curve>)>
 }
 
-impl<C: Coin> Wallet<C> {
-  pub fn new(coin: C) -> Wallet<C> {
+impl<D: CoinDb, C: Coin> Wallet<D, C> {
+  pub fn new(db: D, coin: C) -> Wallet<D, C> {
     Wallet {
-      db: CoinDb {
-        scanned_height: 0,
-        acknowledged_heights: HashMap::new(),
-      },
-
+      db,
       coin,
 
       keys: vec![],
@@ -62,13 +117,12 @@ impl<C: Coin> Wallet<C> {
     }
   }
 
-  pub fn scanned_height(&self) -> usize { self.db.scanned_height }
+  pub fn scanned_height(&self) -> usize { self.db.scanned_height() }
   pub fn acknowledge_height(&mut self, canonical: usize, height: usize) {
-    debug_assert!(!self.db.acknowledged_heights.contains_key(&canonical));
-    self.db.acknowledged_heights.insert(canonical, height);
+    self.db.acknowledge_height(canonical, height);
   }
   pub fn acknowledged_height(&self, canonical: usize) -> usize {
-    self.db.acknowledged_heights[&canonical]
+    self.db.acknowledged_height(canonical)
   }
 
   pub fn add_keys(&mut self, keys: &WalletKeys<C::Curve>) {
@@ -83,7 +137,10 @@ impl<C: Coin> Wallet<C> {
       {
         let mut k = 0;
         while k < self.pending.len() {
-          if height >= self.pending[k].0 {
+          // TODO
+          //if height < self.pending[k].0 {
+          //} else if height == self.pending[k].0 {
+          if height <= self.pending[k].0 {
             self.keys.push((Arc::new(self.pending.swap_remove(k).1), vec![]));
           } else {
             k += 1;
@@ -95,7 +152,7 @@ impl<C: Coin> Wallet<C> {
       for (keys, outputs) in self.keys.iter_mut() {
         outputs.extend(
           self.coin.get_outputs(&block, keys.group_key()).await.iter().cloned().filter(
-            |_output| true // !self.db.handled.contains_key(output.id()) // TODO
+            |output| self.db.add_output(output)
           )
         );
       }
@@ -103,18 +160,23 @@ impl<C: Coin> Wallet<C> {
     Ok(())
   }
 
+  // This should be called whenever new outputs are received, meaning there was a new block
+  // If these outputs were received and sent to Substrate, it should be called after they're
+  // included in a block and we have results to act on
+  // If these outputs weren't sent to Substrate (change), it should be called immediately
+  // with all payments still queued from the last call
   pub async fn prepare_sends(
     &mut self,
     canonical: usize,
     payments: Vec<(C::Address, u64)>
-  ) -> Result<Vec<C::SignableTransaction>, CoinError> {
+  ) -> Result<(Vec<(C::Address, u64)>, Vec<C::SignableTransaction>), CoinError> {
     if payments.len() == 0 {
-      return Ok(vec![]);
+      return Ok((vec![], vec![]));
     }
 
     let acknowledged_height = self.acknowledged_height(canonical);
 
-    // TODO: Log schedule outputs when MAX_OUTPUTS is low
+    // TODO: Log schedule outputs when MAX_OUTPUTS is lower than payments.len()
     // Payments is the first set of TXs in the schedule
     // As each payment re-appears, let mut payments = schedule[payment] where the only input is
     // the source payment
@@ -177,8 +239,6 @@ impl<C: Coin> Wallet<C> {
       }
     }
 
-    // TODO: Remaining payments?
-
-    Ok(txs)
+    Ok((payments, txs))
   }
 }