diff --git a/build.js b/build.js
index a1b2d52..e40c3e3 100644
--- a/build.js
+++ b/build.js
@@ -1,7 +1,8 @@
 var https = require('https')
-var URL = 'https://spdx.org/licenses/licenses.json'
+var SPDX_URL = 'https://spdx.org/licenses/licenses.json'
+var ids = {}
 
-https.get(URL, function (response) {
+https.get(SPDX_URL, function (response) {
   var chunks = []
   response
     .on('data', function (chunk) {
@@ -14,7 +15,7 @@ https.get(URL, function (response) {
     .once('end', function () {
       var body = Buffer.concat(chunks)
       var parsed = JSON.parse(body)
-      var ids = parsed.licenses
+      ids.spdx = parsed.licenses
         .filter(function (license) {
           return license.isOsiApproved
         })
@@ -25,6 +26,41 @@ https.get(URL, function (response) {
           return license.licenseId
         })
         .sort()
-      console.log(JSON.stringify(ids, null, 2))
+      if (ids.osi) compare()
     })
 })
+
+var OSI_URL = 'https://opensource.org/api/license'
+https.get(OSI_URL, function (response) {
+  var chunks = []
+  response
+    .on('data', function (chunk) {
+      chunks.push(chunk)
+    })
+    .once('error', function (error) {
+      console.error(error)
+      process.exit(1)
+    })
+    .once('end', function () {
+      var body = Buffer.concat(chunks)
+      var parsed = JSON.parse(body)
+      ids.osi = parsed
+        .map(function (license) {
+          return license.id
+        })
+        .sort()
+      if (ids.spdx) compare()
+    })
+})
+
+function compare () {
+  console.log(ids)
+  var combined = []
+  ;[ids.spdx, ids.osi].forEach(function (list) {
+    list.forEach(function (id) {
+      if (combined.indexOf(id) === -1) combined.push(id)
+    })
+  })
+  combined.sort()
+  console.log(JSON.stringify(combined, null, 2))
+}