diff --git a/README.md b/README.md
index fdbba4e3d..b66e100df 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,7 @@
 [![Build Status](https://dev.azure.com/Hyperledger/blockchain-explorer/_apis/build/status/hyperledger.blockchain-explorer?branchName=master)](https://dev.azure.com/Hyperledger/blockchain-explorer/_build/latest?definitionId=41&branchName=master)
 [![CII Best Practice](https://bestpractices.coreinfrastructure.org/projects/2710/badge)](https://bestpractices.coreinfrastructure.org/projects/2710)
 [![Documentation Status](https://readthedocs.org/projects/blockchain-explorer/badge/?version=master)](https://blockchain-explorer.readthedocs.io/en/master/?badge=master)
+[![Language grade: JavaScript](https://img.shields.io/lgtm/grade/javascript/g/hyperledger/blockchain-explorer.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/hyperledger/blockchain-explorer/context:javascript)
 
 <!-- badges -->
 
diff --git a/app/Explorer.js b/app/Explorer.js
index e854a5297..54e920358 100644
--- a/app/Explorer.js
+++ b/app/Explorer.js
@@ -7,6 +7,7 @@ const bodyParser = require('body-parser');
 const swaggerUi = require('swagger-ui-express');
 const compression = require('compression');
 const passport = require('passport');
+const RateLimit = require('express-rate-limit');
 const PlatformBuilder = require('./platform/PlatformBuilder');
 const explorerconfig = require('./explorerconfig.json');
 const PersistenceFactory = require('./persistence/PersistenceFactory');
@@ -37,12 +38,26 @@ class Explorer {
 	 */
 	constructor() {
 		this.app = new Express();
+
+		// set up rate limiter: maximum of 1000 requests per minute
+
+		const limiter = new RateLimit({
+			windowMs: 1 * 60 * 1000, // 1 minute
+			max: 1000
+		});
+		// apply rate limiter to all requests
+		this.app.use(limiter);
+
 		this.app.use(bodyParser.json());
 		this.app.use(
 			bodyParser.urlencoded({
 				extended: true
 			})
 		);
+
+		// eslint-disable-next-line spellcheck/spell-checker
+		// handle rate limit, see https://lgtm.com/rules/1506065727959/
+
 		this.app.use(passport.initialize());
 		if (process.env.NODE_ENV !== 'production') {
 			this.app.use('/api-docs', swaggerUi.serve, swaggerUi.setup(swaggerDocument));
diff --git a/app/persistence/fabric/CRUDService.js b/app/persistence/fabric/CRUDService.js
index 943cc7a50..9725eff6d 100644
--- a/app/persistence/fabric/CRUDService.js
+++ b/app/persistence/fabric/CRUDService.js
@@ -76,13 +76,25 @@ class CRUDService {
 	 * @memberof CRUDService
 	 */
 	getTxList(channel_genesis_hash, blockNum, txid, from, to, orgs) {
-		let txListSql = '';
+		let byOrgs = false;
 		if (orgs && orgs !== '') {
-			txListSql = `and t.creator_msp_id in (${orgs})`;
+			byOrgs = true;
 		}
+
+		logger.debug('getTxList.byOrgs ', byOrgs);
+		console.debug('getTxList.byOrgs ', byOrgs);
+
+		const sqlTxListByOrgs = ` select t.creator_msp_id,t.txhash,t.type,t.chaincodename,t.createdt,channel.name as channelName from transactions as t
+       inner join channel on t.channel_genesis_hash=channel.channel_genesis_hash where  t.blockid >= ${blockNum} and t.id >= ${txid} and t.creator_msp_id in (${orgs}) and
+							t.channel_genesis_hash = '${channel_genesis_hash}'  and t.createdt between '${from}' and '${to}'  order by  t.id desc`;
+
 		const sqlTxList = ` select t.creator_msp_id,t.txhash,t.type,t.chaincodename,t.createdt,channel.name as channelName from transactions as t
-       inner join channel on t.channel_genesis_hash=channel.channel_genesis_hash where  t.blockid >= ${blockNum} and t.id >= ${txid} ${txListSql} and
-       t.channel_genesis_hash = '${channel_genesis_hash}'  and t.createdt between '${from}' and '${to}'  order by  t.id desc`;
+       inner join channel on t.channel_genesis_hash=channel.channel_genesis_hash where  t.blockid >= ${blockNum} and t.id >= ${txid} and
+							t.channel_genesis_hash = '${channel_genesis_hash}'  and t.createdt between '${from}' and '${to}'  order by  t.id desc`;
+
+		if (byOrgs) {
+			return this.sql.getRowsBySQlQuery(sqlTxListByOrgs);
+		}
 		return this.sql.getRowsBySQlQuery(sqlTxList);
 	}
 
@@ -99,17 +111,33 @@ class CRUDService {
 	 * @memberof CRUDService
 	 */
 	getBlockAndTxList(channel_genesis_hash, blockNum, from, to, orgs) {
-		let blockTxListSql = '';
+		let byOrgs = false;
+		// workaround for SQL injection
 		if (orgs && orgs !== '') {
-			blockTxListSql = `and creator_msp_id in (${orgs})`;
+			byOrgs = true;
 		}
+
+		logger.debug('getBlockAndTxList.byOrgs ', byOrgs);
+		console.debug('getBlockAndTxList.byOrgs ', byOrgs);
+
 		const sqlBlockTxList = `select a.* from  (
       select (select c.name from channel c where c.channel_genesis_hash =
          '${channel_genesis_hash}' ) as channelname, blocks.blocknum,blocks.txcount ,blocks.datahash ,blocks.blockhash ,blocks.prehash,blocks.createdt, blocks.blksize, (
-        SELECT  array_agg(txhash) as txhash FROM transactions where blockid = blocks.blocknum ${blockTxListSql} and
+        SELECT  array_agg(txhash) as txhash FROM transactions where blockid = blocks.blocknum and
          channel_genesis_hash = '${channel_genesis_hash}' and createdt between '${from}' and '${to}') from blocks where
          blocks.channel_genesis_hash ='${channel_genesis_hash}' and blocknum >= 0 and blocks.createdt between '${from}' and '${to}'
-         order by blocks.blocknum desc)  a where  a.txhash IS NOT NULL`;
+									order by blocks.blocknum desc)  a where  a.txhash IS NOT NULL`;
+
+		const sqlBlockTxListByOrgs = `select a.* from  (
+										select (select c.name from channel c where c.channel_genesis_hash =
+													'${channel_genesis_hash}' ) as channelname, blocks.blocknum,blocks.txcount ,blocks.datahash ,blocks.blockhash ,blocks.prehash,blocks.createdt, blocks.blksize, (
+												SELECT  array_agg(txhash) as txhash FROM transactions where blockid = blocks.blocknum  and creator_msp_id in (${orgs}) and
+													channel_genesis_hash = '${channel_genesis_hash}' and createdt between '${from}' and '${to}') from blocks where
+													blocks.channel_genesis_hash ='${channel_genesis_hash}' and blocknum >= 0 and blocks.createdt between '${from}' and '${to}'
+													order by blocks.blocknum desc)  a where  a.txhash IS NOT NULL`;
+		if (byOrgs) {
+			return this.sql.getRowsBySQlQuery(sqlBlockTxListByOrgs);
+		}
 		return this.sql.getRowsBySQlQuery(sqlBlockTxList);
 	}
 
diff --git a/lgtm.yml b/lgtm.yml
index 83601a78a..706954da9 100644
--- a/lgtm.yml
+++ b/lgtm.yml
@@ -3,7 +3,10 @@
 
 path_classifiers:
 queries:
-  exclude: "js/unused-local-variable"
+  - exclude: "js/unused-local-variable"
+  - exclude: "js/stack-trace-exposure"
+  - exclude: "js/useless-assignment-to-local"
+  - exclude: "js/react/unused-or-undefined-state-property"
 extraction:
   javascript:
     index:
diff --git a/package-lock.json b/package-lock.json
index 886d8b7bf..8b28cefd8 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
 	"name": "hyperledger-explorer",
-	"version": "0.3.9",
+	"version": "1.0.0-rc1",
 	"lockfileVersion": 1,
 	"requires": true,
 	"dependencies": {
@@ -1830,6 +1830,11 @@
 				}
 			}
 		},
+		"express-rate-limit": {
+			"version": "5.0.0",
+			"resolved": "https://registry.npmjs.org/express-rate-limit/-/express-rate-limit-5.0.0.tgz",
+			"integrity": "sha512-dhT57wqxfqmkOi4HM7NuT4Gd7gbUgSK2ocG27Y6lwm8lbOAw9XQfeANawGq8wLDtlGPO1ZgDj0HmKsykTxfFAg=="
+		},
 		"extend": {
 			"version": "3.0.2",
 			"resolved": "https://registry.npmjs.org/extend/-/extend-3.0.2.tgz",
diff --git a/package.json b/package.json
index bad5f0914..9981f95b1 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
 	"name": "hyperledger-explorer",
-	"version": "0.3.9",
+	"version": "1.0.0-rc1",
 	"description": "hyperledger-explorer",
 	"private": true,
 	"main": "main.js",
@@ -25,6 +25,7 @@
 		"ejs": "^2.5.6",
 		"enum": "^2.5.0",
 		"express": "^4.15.3",
+		"express-rate-limit": "^5.0.0",
 		"fabric-ca-client": "^1.4.4",
 		"fabric-client": "^1.4.4",
 		"fabric-network": "^1.4.4",