diff --git a/modules/admixerBidAdapter.js b/modules/admixerBidAdapter.js
index 5c01152200e..bb9a6dd44a3 100644
--- a/modules/admixerBidAdapter.js
+++ b/modules/admixerBidAdapter.js
@@ -46,11 +46,10 @@ export const spec = {
       Object.keys(bid).forEach(key => imp[key] = bid[key]);
       payload.imps.push(imp);
     });
-    const payloadString = JSON.stringify(payload);
     return {
-      method: 'GET',
+      method: 'POST',
       url: endpointUrl || ENDPOINT_URL,
-      data: `data=${payloadString}`,
+      data: payload,
     };
   },
   /**
diff --git a/test/spec/modules/admixerBidAdapter_spec.js b/test/spec/modules/admixerBidAdapter_spec.js
index 27dc895e3a4..6dfde0d0652 100644
--- a/test/spec/modules/admixerBidAdapter_spec.js
+++ b/test/spec/modules/admixerBidAdapter_spec.js
@@ -67,7 +67,7 @@ describe('AdmixerAdapter', function () {
 
     it('should add referrer and imp to be equal bidRequest', function () {
       const request = spec.buildRequests(validRequest, bidderRequest);
-      const payload = JSON.parse(request.data.substr(5));
+      const payload = request.data;
       expect(payload.referrer).to.not.be.undefined;
       expect(payload.imps[0]).to.deep.equal(validRequest[0]);
     });
@@ -75,7 +75,7 @@ describe('AdmixerAdapter', function () {
     it('sends bid request to ENDPOINT via GET', function () {
       const request = spec.buildRequests(validRequest, bidderRequest);
       expect(request.url).to.equal(ENDPOINT_URL);
-      expect(request.method).to.equal('GET');
+      expect(request.method).to.equal('POST');
     });
 
     it('sends bid request to CUSTOM_ENDPOINT via GET', function () {
@@ -85,7 +85,7 @@ describe('AdmixerAdapter', function () {
       });
       const request = config.runWithBidder(BIDDER_CODE, () => spec.buildRequests(validRequest, bidderRequest));
       expect(request.url).to.equal(ENDPOINT_URL_CUSTOM);
-      expect(request.method).to.equal('GET');
+      expect(request.method).to.equal('POST');
     });
   });