diff --git a/middleware/interpolate.js b/middleware/interpolate.js
index f28e04db..b3fb5cdf 100644
--- a/middleware/interpolate.js
+++ b/middleware/interpolate.js
@@ -1,5 +1,6 @@
 const async = require('async');
 const logger = require( 'pelias-logger' ).get( 'api' );
+const source_mapping = require('../helper/type_mapping').source_mapping;
 const _ = require('lodash');
 
 /**
@@ -64,13 +65,13 @@ function setup(service, should_execute) {
         source_result.name.default = `${interpolation_result.properties.number} ${source_result.name.default}`;
 
         // -- source --
-        if (interpolation_result.properties.source === 'OSM') {
-          source_result.source = 'openstreetmap';
-        } else if (interpolation_result.properties.source === 'OA') {
-          source_result.source = 'openaddresses';
-        } else {
-          source_result.source = 'mixed';
-        }
+        // lookup the lowercased source, defaulting to 'mixed' when not found
+        // the source mapping is a jagged string->array, so default to 'mixed' as an array
+        //  to ensure that subscript works
+        source_result.source = _.defaultTo(
+          source_mapping[_.toLower(interpolation_result.properties.source)],
+          ['mixed']
+        )[0];
 
         // -- source_id --
         // note: interpolated values have no source_id
@@ -109,7 +110,7 @@ function setup(service, should_execute) {
     });
 
   };
-  
+
 }
 
 module.exports = setup;
diff --git a/test/unit/middleware/interpolate.js b/test/unit/middleware/interpolate.js
index 61da272f..de855854 100644
--- a/test/unit/middleware/interpolate.js
+++ b/test/unit/middleware/interpolate.js
@@ -225,8 +225,8 @@ module.exports.tests.success_conditions = (test, common) => {
         callback(null, {
           properties: {
             number: 17,
-            source: 'OSM',
-            source_id: 'openstreetmap source id',
+            source: 'Source Abbr 1',
+            source_id: 'source 1 source id',
             lat: 12.121212,
             lon: 21.212121
           }
@@ -236,8 +236,8 @@ module.exports.tests.success_conditions = (test, common) => {
         callback(null, {
           properties: {
             number: 18,
-            source: 'OA',
-            source_id: 'openaddresses source id',
+            source: 'Source Abbr 2',
+            source_id: 'source 2 source id',
             lat: 13.131313,
             lon: 31.313131
           }
@@ -264,7 +264,13 @@ module.exports.tests.success_conditions = (test, common) => {
     const logger = require('pelias-mock-logger')();
 
     const controller = proxyquire('../../../middleware/interpolate', {
-      'pelias-logger': logger
+      'pelias-logger': logger,
+      '../helper/type_mapping': {
+        source_mapping: {
+          'source abbr 1': ['full source name 1'],
+          'source abbr 2': ['full source name 2']
+        }
+      }
     })(service, () => true);
 
     const req = {
@@ -331,8 +337,8 @@ module.exports.tests.success_conditions = (test, common) => {
             name: {
               default: '17 street name 1'
             },
-            source: 'openstreetmap',
-            source_id: 'openstreetmap source id',
+            source: 'full source name 1',
+            source_id: 'source 1 source id',
             address_parts: {
               number: 17
             },
@@ -348,8 +354,8 @@ module.exports.tests.success_conditions = (test, common) => {
             name: {
               default: '18 street name 3'
             },
-            source: 'openaddresses',
-            source_id: 'openaddresses source id',
+            source: 'full source name 2',
+            source_id: 'source 2 source id',
             address_parts: {
               number: 18
             },