diff --git a/package.json b/package.json
index 5157fd8..7d8c935 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "fergies-inverted-index",
-  "version": "13.0.0-rc.3",
+  "version": "13.0.0-rc.4",
   "description": "An inverted index that allows javascript objects to be easily serialised and retrieved using promises and map-reduce",
   "browser": "src/entrypoints/browser.js",
   "main": "src/entrypoints/node.js",
diff --git a/src/main.js b/src/main.js
index 9bfabc5..b0477de 100644
--- a/src/main.js
+++ b/src/main.js
@@ -17,12 +17,13 @@ export class Main {
         keyEncoding: charwise,
         valueEncoding: 'json'
       }),
-      tokenParser: new TokenParser(),
       ...ops
     }
 
-    const r = read(ops)
-    const w = write(ops)
+    const tokenParser = new TokenParser(ops.caseSensitive)
+
+    const r = read(ops, tokenParser)
+    const w = write(ops, tokenParser)
 
     // timestamp with time of creation (if not created already)
     // note: async, so this is "fire and forget"
@@ -58,7 +59,7 @@ export class Main {
     this.SORT = r.SORT
     this.STORE = ops.db
     this.TIMESTAMP_LAST_UPDATED = w.TIMESTAMP_LAST_UPDATED
-    this.TOKEN_PARSER = ops.tokenParser
+    this.TOKEN_PARSER = tokenParser
   }
 
   flattenMatchArrayInResults (results) {
diff --git a/src/parseToken.js b/src/parseToken.js
index 2918418..95cdcaa 100644
--- a/src/parseToken.js
+++ b/src/parseToken.js
@@ -6,14 +6,29 @@ charwise.HI = undefined
 // <fieldname>:<value>. Turn key into json object that is of the
 // format {FIELD: ..., VALUE: {GTE: ..., LTE ...}}
 export class TokenParser {
-  constructor (availableFields = []) {
-    this.setAvailableFields(availableFields)
+  availableFields = []
+  #caseSensitive
+
+  constructor (caseSensitive) {
+    this.#caseSensitive = caseSensitive
   }
 
-  setAvailableFields (availableFields) {
+  setAvailableFields = availableFields => {
     this.availableFields = availableFields
   }
 
+  #setCaseSensitivity = token => {
+    const setCase = str =>
+      this.#caseSensitive || typeof str !== 'string' ? str : str.toLowerCase()
+    return {
+      FIELD: token.FIELD.map(setCase),
+      VALUE: {
+        GTE: setCase(token.VALUE.GTE),
+        LTE: setCase(token.VALUE.LTE)
+      }
+    }
+  }
+
   parse (token) {
     // case: <value>
     // case: <FIELD>:<VALUE>
@@ -30,23 +45,23 @@ export class TokenParser {
       // a part of the value. This accounts for occasions where the value itself
       // has a ':'.
       if (token.indexOf(':') === -1) {
-        return {
+        return this.#setCaseSensitivity({
           FIELD: this.availableFields,
           VALUE: {
             GTE: token,
             LTE: token
           }
-        }
+        })
       }
 
       const [field, ...value] = token.split(':')
-      return {
+      return this.#setCaseSensitivity({
         FIELD: [field],
         VALUE: {
           GTE: value.join(':'),
           LTE: value.join(':')
         }
-      }
+      })
     }
 
     if (typeof token === 'number') {
@@ -103,14 +118,14 @@ export class TokenParser {
 
     // parse object FIELD
     if (typeof token.FIELD === 'undefined') {
-      return {
+      return this.#setCaseSensitivity({
         FIELD: this.availableFields,
         ...token
-      }
+      })
     }
     // Allow FIELD to be an array or a string
     token.FIELD = [token.FIELD].flat()
 
-    return token
+    return this.#setCaseSensitivity(token)
   }
 }
diff --git a/src/read.js b/src/read.js
index 103995b..e7f54ea 100644
--- a/src/read.js
+++ b/src/read.js
@@ -4,7 +4,7 @@ import charwise from 'charwise'
 charwise.LO = null
 charwise.HI = undefined
 
-export default function (ops) {
+export default function (ops, tokenParser) {
   const isString = s => typeof s === 'string'
 
   const queryReplace = token => {
@@ -32,18 +32,6 @@ export default function (ops) {
     return token
   }
 
-  const setCaseSensitivity = token => {
-    const setCase = str =>
-      ops.caseSensitive || typeof str !== 'string' ? str : str.toLowerCase()
-    return {
-      FIELD: token.FIELD.map(setCase),
-      VALUE: {
-        GTE: setCase(token.VALUE.GTE),
-        LTE: setCase(token.VALUE.LTE)
-      }
-    }
-  }
-
   // If this token is a stopword then return 'undefined'
   const removeStopwords = token =>
     token.VALUE.GTE === token.VALUE.LTE &&
@@ -67,9 +55,10 @@ export default function (ops) {
       try {
         testForBreak(token)
 
-        token = ops.tokenParser.parse(token)
+        token = tokenParser.parse(token)
+
         // testForBreak(token) // ?
-        token = await setCaseSensitivity(token)
+        //        token = await setCaseSensitivity(token)
         // testForBreak(token) // ?
         token = await removeStopwords(token)
         // testForBreak(token) // ?
@@ -216,7 +205,7 @@ export default function (ops) {
   // return a bucket of IDs. Key is an object like this:
   // {gte:..., lte:...} (gte/lte == greater/less than or equal)
   const BUCKET = token => {
-    token = ops.tokenParser.parse(token)
+    token = tokenParser.parse(token)
     return GET(token).then(result => ({
       _id: [...result.reduce((acc, cur) => acc.add(cur._id), new Set())].sort(),
       VALUE: token.VALUE,
@@ -245,7 +234,7 @@ export default function (ops) {
 
   const BOUNDING_VALUE = (token, reverse) =>
     RANGE({
-      ...ops.tokenParser.parse(token),
+      ...tokenParser.parse(token),
       LIMIT: 1,
       REVERSE: reverse
     }).then(max =>
@@ -265,7 +254,7 @@ export default function (ops) {
     )
 
   const DIST = token => {
-    token = ops.tokenParser.parse(token)
+    token = tokenParser.parse(token)
     return Promise.all(
       token.FIELD.map(field => {
         let lte = token.VALUE.LTE
@@ -313,7 +302,7 @@ export default function (ops) {
     )
 
   const FACET = token => {
-    token = ops.tokenParser.parse(token)
+    token = tokenParser.parse(token)
     return Promise.all(
       token.FIELD.map(field =>
         getRange({
diff --git a/src/write.js b/src/write.js
index 7a158bb..c2ac382 100644
--- a/src/write.js
+++ b/src/write.js
@@ -1,7 +1,7 @@
 import trav from 'traverse'
 import reader from './read.js'
 
-export default function (ops) {
+export default function (ops, tokenParser) {
   // TODO: set reset this to the max value every time the DB is restarted
   let incrementalId = 0
 
@@ -32,7 +32,13 @@ export default function (ops) {
             if (!ops.stopwords.includes(this.node)) {
               const key = JSON.stringify([
                 fieldName,
-                [this.node].flat(Infinity)
+                [this.node]
+                  .flat(Infinity)
+                  .map(item =>
+                    typeof item === 'string' && !ops.caseSensitive
+                      ? item.toLowerCase()
+                      : item
+                  )
               ])
               // bump to lower case if not case sensitive
               keys.push(ops.caseSensitive ? key : key.toLowerCase())
@@ -207,7 +213,7 @@ export default function (ops) {
         )
       )
       .then(() => reader(ops).FIELDS())
-      .then(fields => ops.tokenParser.setAvailableFields(fields))
+      .then(fields => tokenParser.setAvailableFields(fields))
 
   const PUT = (docs, putOptions = {}) =>
     writer(
@@ -223,7 +229,7 @@ export default function (ops) {
       .then(TIMESTAMP_LAST_UPDATED)
       .then(async passThrough => {
         // TODO: reader should not be inited here
-        ops.tokenParser.setAvailableFields(await reader(ops).FIELDS())
+        tokenParser.setAvailableFields(await reader(ops).FIELDS())
         return passThrough
       })
 
diff --git a/test/src/DISTINCT-test.js b/test/src/DISTINCT-test.js
index 30e07a6..105af36 100644
--- a/test/src/DISTINCT-test.js
+++ b/test/src/DISTINCT-test.js
@@ -101,7 +101,13 @@ const data = [
 
 test('create index', t => {
   t.plan(1)
-  t.ok((global[indexName] = new InvertedIndex({ name: indexName })), !undefined)
+  t.ok(
+    (global[indexName] = new InvertedIndex({
+      name: indexName,
+      caseSensitive: false
+    })),
+    !undefined
+  )
 })
 
 test('can add some data', t => {
@@ -117,10 +123,10 @@ test('get DISTINCT values for one field', t => {
     })
     .then(result =>
       t.deepEqual(result, [
-        { FIELD: 'drivetrain', VALUE: 'Diesel' },
-        { FIELD: 'drivetrain', VALUE: 'Electric' },
-        { FIELD: 'drivetrain', VALUE: 'Hybrid' },
-        { FIELD: 'drivetrain', VALUE: 'Petrol' }
+        { FIELD: 'drivetrain', VALUE: 'diesel' },
+        { FIELD: 'drivetrain', VALUE: 'electric' },
+        { FIELD: 'drivetrain', VALUE: 'hybrid' },
+        { FIELD: 'drivetrain', VALUE: 'petrol' }
       ])
     )
 })
@@ -133,13 +139,13 @@ test('get DISTINCT values for two fields', t => {
     })
     .then(result =>
       t.deepEqual(result, [
-        { FIELD: 'drivetrain', VALUE: 'Diesel' },
-        { FIELD: 'drivetrain', VALUE: 'Electric' },
-        { FIELD: 'drivetrain', VALUE: 'Hybrid' },
-        { FIELD: 'drivetrain', VALUE: 'Petrol' },
-        { FIELD: 'make', VALUE: 'BMW' },
-        { FIELD: 'make', VALUE: 'Tesla' },
-        { FIELD: 'make', VALUE: 'Volvo' }
+        { FIELD: 'drivetrain', VALUE: 'diesel' },
+        { FIELD: 'drivetrain', VALUE: 'electric' },
+        { FIELD: 'drivetrain', VALUE: 'hybrid' },
+        { FIELD: 'drivetrain', VALUE: 'petrol' },
+        { FIELD: 'make', VALUE: 'bmw' },
+        { FIELD: 'make', VALUE: 'tesla' },
+        { FIELD: 'make', VALUE: 'volvo' }
       ])
     )
 })
@@ -155,10 +161,29 @@ test('get DISTINCT values for two fields with GTE', t => {
     })
     .then(result =>
       t.deepEqual(result, [
-        { FIELD: 'drivetrain', VALUE: 'Hybrid' },
-        { FIELD: 'drivetrain', VALUE: 'Petrol' },
-        { FIELD: 'make', VALUE: 'Tesla' },
-        { FIELD: 'make', VALUE: 'Volvo' }
+        { FIELD: 'drivetrain', VALUE: 'hybrid' },
+        { FIELD: 'drivetrain', VALUE: 'petrol' },
+        { FIELD: 'make', VALUE: 'tesla' },
+        { FIELD: 'make', VALUE: 'volvo' }
+      ])
+    )
+})
+
+test('get DISTINCT values for two fields with GTE (case insensitive)', t => {
+  t.plan(1)
+  global[indexName]
+    .DISTINCT({
+      FIELD: ['drivetrain', 'make'],
+      VALUE: {
+        GTE: 'f'
+      }
+    })
+    .then(result =>
+      t.deepEqual(result, [
+        { FIELD: 'drivetrain', VALUE: 'hybrid' },
+        { FIELD: 'drivetrain', VALUE: 'petrol' },
+        { FIELD: 'make', VALUE: 'tesla' },
+        { FIELD: 'make', VALUE: 'volvo' }
       ])
     )
 })
@@ -176,13 +201,13 @@ test('get DISTINCT values with two clauses', t => {
     )
     .then(result =>
       t.deepEqual(result, [
-        { FIELD: 'drivetrain', VALUE: 'Diesel' },
-        { FIELD: 'drivetrain', VALUE: 'Electric' },
-        { FIELD: 'drivetrain', VALUE: 'Hybrid' },
-        { FIELD: 'drivetrain', VALUE: 'Petrol' },
-        { FIELD: 'make', VALUE: 'BMW' },
-        { FIELD: 'make', VALUE: 'Tesla' },
-        { FIELD: 'make', VALUE: 'Volvo' }
+        { FIELD: 'drivetrain', VALUE: 'diesel' },
+        { FIELD: 'drivetrain', VALUE: 'electric' },
+        { FIELD: 'drivetrain', VALUE: 'hybrid' },
+        { FIELD: 'drivetrain', VALUE: 'petrol' },
+        { FIELD: 'make', VALUE: 'bmw' },
+        { FIELD: 'make', VALUE: 'tesla' },
+        { FIELD: 'make', VALUE: 'volvo' }
       ])
     )
 })
@@ -201,11 +226,11 @@ test('get DISTINCT values with two clauses', t => {
     )
     .then(result =>
       t.deepEqual(result, [
-        { FIELD: 'drivetrain', VALUE: 'Diesel' },
-        { FIELD: 'drivetrain', VALUE: 'Electric' },
-        { FIELD: 'make', VALUE: 'BMW' },
-        { FIELD: 'make', VALUE: 'Tesla' },
-        { FIELD: 'make', VALUE: 'Volvo' }
+        { FIELD: 'drivetrain', VALUE: 'diesel' },
+        { FIELD: 'drivetrain', VALUE: 'electric' },
+        { FIELD: 'make', VALUE: 'bmw' },
+        { FIELD: 'make', VALUE: 'tesla' },
+        { FIELD: 'make', VALUE: 'volvo' }
       ])
     )
 })
@@ -223,10 +248,10 @@ test('get DISTINCT values with two identical clauses', t => {
     )
     .then(result =>
       t.deepEqual(result, [
-        { FIELD: 'drivetrain', VALUE: 'Diesel' },
-        { FIELD: 'drivetrain', VALUE: 'Electric' },
-        { FIELD: 'drivetrain', VALUE: 'Hybrid' },
-        { FIELD: 'drivetrain', VALUE: 'Petrol' }
+        { FIELD: 'drivetrain', VALUE: 'diesel' },
+        { FIELD: 'drivetrain', VALUE: 'electric' },
+        { FIELD: 'drivetrain', VALUE: 'hybrid' },
+        { FIELD: 'drivetrain', VALUE: 'petrol' }
       ])
     )
 })
@@ -239,18 +264,18 @@ test('get DISTINCT values for three fields', t => {
     })
     .then(result =>
       t.deepEqual(result, [
-        { FIELD: 'drivetrain', VALUE: 'Diesel' },
-        { FIELD: 'drivetrain', VALUE: 'Electric' },
-        { FIELD: 'drivetrain', VALUE: 'Hybrid' },
-        { FIELD: 'drivetrain', VALUE: 'Petrol' },
-        { FIELD: 'make', VALUE: 'BMW' },
-        { FIELD: 'make', VALUE: 'Tesla' },
-        { FIELD: 'make', VALUE: 'Volvo' },
-        { FIELD: 'colour', VALUE: 'Black' },
-        { FIELD: 'colour', VALUE: 'Blue' },
-        { FIELD: 'colour', VALUE: 'Red' },
-        { FIELD: 'colour', VALUE: 'Silver' },
-        { FIELD: 'colour', VALUE: 'White' }
+        { FIELD: 'drivetrain', VALUE: 'diesel' },
+        { FIELD: 'drivetrain', VALUE: 'electric' },
+        { FIELD: 'drivetrain', VALUE: 'hybrid' },
+        { FIELD: 'drivetrain', VALUE: 'petrol' },
+        { FIELD: 'make', VALUE: 'bmw' },
+        { FIELD: 'make', VALUE: 'tesla' },
+        { FIELD: 'make', VALUE: 'volvo' },
+        { FIELD: 'colour', VALUE: 'black' },
+        { FIELD: 'colour', VALUE: 'blue' },
+        { FIELD: 'colour', VALUE: 'red' },
+        { FIELD: 'colour', VALUE: 'silver' },
+        { FIELD: 'colour', VALUE: 'white' }
       ])
     )
 })
@@ -259,24 +284,24 @@ test('get DISTINCT values for ALL fields using {}', t => {
   t.plan(1)
   global[indexName].DISTINCT({}).then(result =>
     t.deepEqual(result, [
-      { FIELD: 'colour', VALUE: 'Black' },
-      { FIELD: 'colour', VALUE: 'Blue' },
-      { FIELD: 'colour', VALUE: 'Red' },
-      { FIELD: 'colour', VALUE: 'Silver' },
-      { FIELD: 'colour', VALUE: 'White' },
-      { FIELD: 'drivetrain', VALUE: 'Diesel' },
-      { FIELD: 'drivetrain', VALUE: 'Electric' },
-      { FIELD: 'drivetrain', VALUE: 'Hybrid' },
-      { FIELD: 'drivetrain', VALUE: 'Petrol' },
-      { FIELD: 'make', VALUE: 'BMW' },
-      { FIELD: 'make', VALUE: 'Tesla' },
-      { FIELD: 'make', VALUE: 'Volvo' },
+      { FIELD: 'colour', VALUE: 'black' },
+      { FIELD: 'colour', VALUE: 'blue' },
+      { FIELD: 'colour', VALUE: 'red' },
+      { FIELD: 'colour', VALUE: 'silver' },
+      { FIELD: 'colour', VALUE: 'white' },
+      { FIELD: 'drivetrain', VALUE: 'diesel' },
+      { FIELD: 'drivetrain', VALUE: 'electric' },
+      { FIELD: 'drivetrain', VALUE: 'hybrid' },
+      { FIELD: 'drivetrain', VALUE: 'petrol' },
+      { FIELD: 'make', VALUE: 'bmw' },
+      { FIELD: 'make', VALUE: 'tesla' },
+      { FIELD: 'make', VALUE: 'volvo' },
       { FIELD: 'model', VALUE: '3-series' },
       { FIELD: 'model', VALUE: '5-series' },
-      { FIELD: 'model', VALUE: 'S' },
-      { FIELD: 'model', VALUE: 'X' },
-      { FIELD: 'model', VALUE: 'XC60' },
-      { FIELD: 'model', VALUE: 'XC90' },
+      { FIELD: 'model', VALUE: 's' },
+      { FIELD: 'model', VALUE: 'x' },
+      { FIELD: 'model', VALUE: 'xc60' },
+      { FIELD: 'model', VALUE: 'xc90' },
       { FIELD: 'price', VALUE: 33114 },
       { FIELD: 'price', VALUE: 37512 },
       { FIELD: 'price', VALUE: 44274 },
@@ -305,24 +330,24 @@ test('get DISTINCT values for ALL fields using no param (DISTINCT())', t => {
   t.plan(1)
   global[indexName].DISTINCT().then(result =>
     t.deepEqual(result, [
-      { FIELD: 'colour', VALUE: 'Black' },
-      { FIELD: 'colour', VALUE: 'Blue' },
-      { FIELD: 'colour', VALUE: 'Red' },
-      { FIELD: 'colour', VALUE: 'Silver' },
-      { FIELD: 'colour', VALUE: 'White' },
-      { FIELD: 'drivetrain', VALUE: 'Diesel' },
-      { FIELD: 'drivetrain', VALUE: 'Electric' },
-      { FIELD: 'drivetrain', VALUE: 'Hybrid' },
-      { FIELD: 'drivetrain', VALUE: 'Petrol' },
-      { FIELD: 'make', VALUE: 'BMW' },
-      { FIELD: 'make', VALUE: 'Tesla' },
-      { FIELD: 'make', VALUE: 'Volvo' },
+      { FIELD: 'colour', VALUE: 'black' },
+      { FIELD: 'colour', VALUE: 'blue' },
+      { FIELD: 'colour', VALUE: 'red' },
+      { FIELD: 'colour', VALUE: 'silver' },
+      { FIELD: 'colour', VALUE: 'white' },
+      { FIELD: 'drivetrain', VALUE: 'diesel' },
+      { FIELD: 'drivetrain', VALUE: 'electric' },
+      { FIELD: 'drivetrain', VALUE: 'hybrid' },
+      { FIELD: 'drivetrain', VALUE: 'petrol' },
+      { FIELD: 'make', VALUE: 'bmw' },
+      { FIELD: 'make', VALUE: 'tesla' },
+      { FIELD: 'make', VALUE: 'volvo' },
       { FIELD: 'model', VALUE: '3-series' },
       { FIELD: 'model', VALUE: '5-series' },
-      { FIELD: 'model', VALUE: 'S' },
-      { FIELD: 'model', VALUE: 'X' },
-      { FIELD: 'model', VALUE: 'XC60' },
-      { FIELD: 'model', VALUE: 'XC90' },
+      { FIELD: 'model', VALUE: 's' },
+      { FIELD: 'model', VALUE: 'x' },
+      { FIELD: 'model', VALUE: 'xc60' },
+      { FIELD: 'model', VALUE: 'xc90' },
       { FIELD: 'price', VALUE: 33114 },
       { FIELD: 'price', VALUE: 37512 },
       { FIELD: 'price', VALUE: 44274 },