diff --git a/server/lib/api/address.js b/server/lib/api/address.js
index 5b19c4a..dfec674 100644
--- a/server/lib/api/address.js
+++ b/server/lib/api/address.js
@@ -11,7 +11,13 @@ module.exports = function AddressAPI(router) {
   router.get('/addr/:addr', (req, res) => {
     const addr = req.params.addr || '';
 
-    db.txs.getTxByAddress(addr, 0, 999999999, (error, txs) => {
+    if (!util.isBitcoinAddress(addr)) {
+      return res.status(404).send({
+        error: 'Invalid bitcoin address',
+      });
+    }
+
+    return db.txs.getTxByAddress(addr, 0, 999999999, (error, txs) => {
       if (error) {
         logger.log('error',
           `getTxByBlock ${error}`);
diff --git a/server/lib/api/block.js b/server/lib/api/block.js
index 5aac849..ee541e4 100644
--- a/server/lib/api/block.js
+++ b/server/lib/api/block.js
@@ -7,7 +7,7 @@ module.exports = function BlockAPI(router) {
     const blockHash = req.params.blockHash;
 
     if (!util.isBlockHash(blockHash)) {
-      return res.status(400).send({
+      return res.status(404).send({
         error: 'Invalid bitcoin address',
       });
     }