diff --git a/packages/api-explorer/__tests__/Params.test.jsx b/packages/api-explorer/__tests__/Params.test.jsx
index ad71232a1..d0def3840 100644
--- a/packages/api-explorer/__tests__/Params.test.jsx
+++ b/packages/api-explorer/__tests__/Params.test.jsx
@@ -7,6 +7,7 @@ const Description = require('../src/form-components/DescriptionField');
 const createParams = require('../src/Params');
 
 const Oas = require('../src/lib/Oas');
+const { Operation } = Oas;
 const petstore = require('./fixtures/petstore/oas.json');
 
 const oas = new Oas(petstore);
@@ -60,6 +61,34 @@ test('boolean should render as <select>', () => {
   expect(select.find('option').map(el => el.text())).toEqual(['', 'true', 'false']);
 });
 
+test('json should render as <textarea>', () => {
+  const jsonOperation = new Operation(oas, '/path', 'post', {
+    requestBody: {
+      content: {
+        'application/json': {
+          schema: {
+            type: 'object',
+            required: ['a'],
+            properties: {
+              a: {
+                type: 'json',
+              },
+            },
+          },
+        },
+      },
+    },
+  });
+
+  const params = mount(
+    <div>
+      <Params {...props} operation={jsonOperation} />
+    </div>,
+  );
+
+  expect(params.find('textarea').length).toBe(1);
+});
+
 describe('x-explorer-enabled', () => {
   const oasWithExplorerDisabled = Object.assign({}, oas, { [extensions.EXPLORER_ENABLED]: false });
   const ParamsWithExplorerDisabled = createParams(oasWithExplorerDisabled);
diff --git a/packages/api-explorer/__tests__/lib/oas-to-har.test.js b/packages/api-explorer/__tests__/lib/oas-to-har.test.js
index 98b92ca8e..62956d6f2 100644
--- a/packages/api-explorer/__tests__/lib/oas-to-har.test.js
+++ b/packages/api-explorer/__tests__/lib/oas-to-har.test.js
@@ -675,6 +675,92 @@ describe('body values', () => {
       ).log.entries[0].request.postData.text,
     ).toEqual(JSON.stringify(true));
   });
+
+  describe('`json` type', () => {
+    it('should work for refs that require a lookup', () => {
+      expect(
+        oasToHar(
+          {
+            components: {
+              requestBodies: {
+                schema: {
+                  content: {
+                    'application/json': {
+                      schema: { type: 'object', properties: { a: { type: 'json' } } },
+                    },
+                  },
+                },
+              },
+            },
+          },
+          {
+            path: '/body',
+            method: 'get',
+            requestBody: {
+              $ref: '#/components/requestBodies/schema',
+            },
+          },
+          { body: { a: '{ "b": 1 }' } },
+        ).log.entries[0].request.postData.text,
+      ).toEqual(JSON.stringify({ a: JSON.parse('{ "b": 1 }') }));
+    });
+
+    it('should leave invalid JSON as strings', () => {
+      expect(
+        oasToHar(
+          {},
+          {
+            path: '/body',
+            method: 'post',
+            requestBody: {
+              content: {
+                'application/json': {
+                  schema: {
+                    type: 'object',
+                    required: ['a'],
+                    properties: {
+                      a: {
+                        type: 'json',
+                      },
+                    },
+                  },
+                },
+              },
+            },
+          },
+          { body: { a: '{ "b": invalid json' } },
+        ).log.entries[0].request.postData.text,
+      ).toEqual(JSON.stringify({ a: '{ "b": invalid json' }));
+    });
+
+    it('should parse valid JSON as an object', () => {
+      expect(
+        oasToHar(
+          {},
+          {
+            path: '/body',
+            method: 'post',
+            requestBody: {
+              content: {
+                'application/json': {
+                  schema: {
+                    type: 'object',
+                    required: ['a'],
+                    properties: {
+                      a: {
+                        type: 'json',
+                      },
+                    },
+                  },
+                },
+              },
+            },
+          },
+          { body: { a: '{ "b": "valid json" }' } },
+        ).log.entries[0].request.postData.text,
+      ).toEqual(JSON.stringify({ a: JSON.parse('{ "b": "valid json" }') }));
+    });
+  });
 });
 
 describe('formData values', () => {
diff --git a/packages/api-explorer/src/Params.jsx b/packages/api-explorer/src/Params.jsx
index 690a3bd04..36bdb16aa 100644
--- a/packages/api-explorer/src/Params.jsx
+++ b/packages/api-explorer/src/Params.jsx
@@ -4,6 +4,7 @@ const Form = require('react-jsonschema-form').default;
 const UpDownWidget = require('react-jsonschema-form/lib/components/widgets/UpDownWidget').default;
 const TextWidget = require('react-jsonschema-form/lib/components/widgets/TextWidget').default;
 const FileWidget = require('react-jsonschema-form/lib/components/widgets/FileWidget').default;
+const TextAreaWidget = require('react-jsonschema-form/lib/components/widgets/TextAreaWidget').default;
 const DateTimeWidget = require('react-jsonschema-form/lib/components/widgets/DateTimeWidget')
   .default;
 
@@ -56,6 +57,7 @@ function Params({
             integer: UpDownWidget,
             BaseInput,
             SelectWidget,
+            json: TextAreaWidget,
           }}
           onSubmit={onSubmit}
           formData={formData[schema.type]}
diff --git a/packages/api-explorer/src/form-components/SchemaField.jsx b/packages/api-explorer/src/form-components/SchemaField.jsx
index e68474ea7..046fbd20a 100644
--- a/packages/api-explorer/src/form-components/SchemaField.jsx
+++ b/packages/api-explorer/src/form-components/SchemaField.jsx
@@ -5,6 +5,9 @@ const BaseSchemaField = require('react-jsonschema-form/lib/components/fields/Sch
 
 function createSchemaField() {
   function SchemaField(props) {
+    if (props.schema.type === 'json') {
+      return <BaseSchemaField {...props} schema={Object.assign({}, props.schema, { type: 'string' })} uiSchema={{ 'ui:widget': 'json' }} />;
+    }
     if (props.schema.type === 'boolean') {
       props.schema.enumNames = ['true', 'false'];
       return <BaseSchemaField {...props} uiSchema={{ 'ui:widget': 'select' }} />;
diff --git a/packages/api-explorer/src/lib/oas-to-har.js b/packages/api-explorer/src/lib/oas-to-har.js
index c5a263f89..638838f8f 100644
--- a/packages/api-explorer/src/lib/oas-to-har.js
+++ b/packages/api-explorer/src/lib/oas-to-har.js
@@ -156,15 +156,30 @@ module.exports = (
 
   const schema = getSchema(pathOperation, oas) || { schema: {} };
 
+  function stringify(json) {
+    // Default to JSON.stringify
+    har.postData.text = JSON.stringify(
+      typeof json.RAW_BODY !== 'undefined' ? json.RAW_BODY : json,
+    );
+  }
+
   if (schema.schema && Object.keys(schema.schema).length) {
     // If there is formData, then the type is application/x-www-form-urlencoded
     if (Object.keys(formData.formData).length) {
       har.postData.text = querystring.stringify(formData.formData);
     } else if (isPrimitive(formData.body) || Object.keys(formData.body).length) {
-      // Default to JSON.stringify
-      har.postData.text = JSON.stringify(
-        typeof formData.body.RAW_BODY !== 'undefined' ? formData.body.RAW_BODY : formData.body,
-      );
+      try {
+        const jsonTypes = Object.keys(schema.schema.properties).filter(key => schema.schema.properties[key].type === 'json');
+        if (jsonTypes.length) {
+          const cloned = JSON.parse(JSON.stringify(formData.body));
+          jsonTypes.forEach(prop => {
+            cloned[prop] = JSON.parse(cloned[prop]);
+          });
+          stringify(cloned);
+        } else stringify(formData.body);
+      } catch (e) {
+        stringify(formData.body);
+      }
     }
   }