diff --git a/src/formats/formats.js b/src/formats/formats.js
index be48fa28..81566148 100644
--- a/src/formats/formats.js
+++ b/src/formats/formats.js
@@ -3,6 +3,14 @@ import tomlFormatter from './toml';
 import jsonFormatter from './json';
 import FrontmatterFormatter from './frontmatter';
 
+export const supportedFormats = [
+  'markdown',
+  'yaml',
+  'toml',
+  'json',
+  'html',
+];
+
 export const formatToExtension = format => ({
   markdown: 'md',
   yaml: 'yml',
@@ -29,8 +37,11 @@ function formatByName(name) {
     yaml: yamlFormatter,
     toml: tomlFormatter,
     json: jsonFormatter,
+    md: FrontmatterFormatter,
+    markdown: FrontmatterFormatter,
+    html: FrontmatterFormatter,
     frontmatter: FrontmatterFormatter,
-  }[name] || FrontmatterFormatter;
+  }[name];
 }
 
 export function resolveFormat(collectionOrEntity, entry) {
@@ -55,5 +66,5 @@ export function resolveFormat(collectionOrEntity, entry) {
   }
 
   // If no format is specified and it cannot be inferred, return the default.
-  return formatByName();
+  return formatByName('frontmatter');
 }
diff --git a/src/reducers/collections.js b/src/reducers/collections.js
index 01257c4e..e983312d 100644
--- a/src/reducers/collections.js
+++ b/src/reducers/collections.js
@@ -1,10 +1,10 @@
 import { OrderedMap, fromJS } from 'immutable';
-import { has } from 'lodash';
+import { has, get } from 'lodash';
 import consoleError from '../lib/consoleError';
 import { CONFIG_SUCCESS } from '../actions/config';
 import { FILES, FOLDER } from '../constants/collectionTypes';
 import { INFERABLE_FIELDS } from '../constants/fieldInference';
-import { formatToExtension } from '../formats/formats';
+import { formatToExtension, supportedFormats } from '../formats/formats';
 
 const collections = (state = null, action) => {
   const configCollections = action.payload && action.payload.collections;
@@ -31,6 +31,9 @@ function validateCollection(configCollection) {
   if (!has(configCollection, 'folder') && !has(configCollection, 'files')) {
     throw new Error(`Unknown collection type for collection "${ collectionName }". Collections can be either Folder based or File based.`);
   }
+  if (has(configCollection, 'format') && !supportedFormats.includes(get(configCollection, 'format'))) {
+      throw new Error(`Unknown collection format for collection "${ collectionName }". Supported formats are ${ supportedFormats.join(',') }`);
+  }
 }
 
 const selectors = {