diff --git a/.eslintrc.json b/.eslintrc.json
index 39963d32..81104c48 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -1,11 +1,9 @@
 {
   "parserOptions": {
-    "ecmaVersion": 5
+    "ecmaVersion": 6,
+    "sourceType": "module"
   },
   "extends": "eslint:recommended",
-  "env": {
-    "commonjs": true
-  },
   "rules": {
     "strict": [2, "global"],
     "block-scoped-var": 2,
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 70427e62..aa57eb55 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,6 +12,8 @@ jobs:
       - uses: actions/checkout@v2
 
       - uses: purescript-contrib/setup-purescript@main
+        with:
+          purescript: "unstable"
 
       - uses: actions/setup-node@v1
         with:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c5e19e60..42e937eb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@ Notable changes to this project are documented in this file. The format is based
 ## [Unreleased]
 
 Breaking changes:
+- Migrated FFI to ES Modules (#287 by @kl0tl and @JordanMartinez)
 
 New features:
 
diff --git a/package.json b/package.json
index 3ed6897b..8382d607 100644
--- a/package.json
+++ b/package.json
@@ -7,8 +7,8 @@
   },
   "devDependencies": {
     "eslint": "^7.15.0",
-    "purescript-psa": "^0.8.0",
-    "pulp": "^15.0.0",
+    "purescript-psa": "^0.8.2",
+    "pulp": "16.0.0-0",
     "rimraf": "^3.0.2"
   }
 }
diff --git a/src/Control/Apply.js b/src/Control/Apply.js
index 0b4720ca..149f4385 100644
--- a/src/Control/Apply.js
+++ b/src/Control/Apply.js
@@ -1,6 +1,4 @@
-"use strict";
-
-exports.arrayApply = function (fs) {
+export const arrayApply = function (fs) {
   return function (xs) {
     var l = fs.length;
     var k = xs.length;
diff --git a/src/Control/Bind.js b/src/Control/Bind.js
index f21afc29..fa0dbaeb 100644
--- a/src/Control/Bind.js
+++ b/src/Control/Bind.js
@@ -1,6 +1,4 @@
-"use strict";
-
-exports.arrayBind = function (arr) {
+export const arrayBind = function (arr) {
   return function (f) {
     var result = [];
     for (var i = 0, l = arr.length; i < l; i++) {
diff --git a/src/Data/Bounded.js b/src/Data/Bounded.js
index 246f8ac8..094350bd 100644
--- a/src/Data/Bounded.js
+++ b/src/Data/Bounded.js
@@ -1,10 +1,8 @@
-"use strict";
+export const topInt = 2147483647;
+export const bottomInt = -2147483648;
 
-exports.topInt = 2147483647;
-exports.bottomInt = -2147483648;
+export const topChar = String.fromCharCode(65535);
+export const bottomChar = String.fromCharCode(0);
 
-exports.topChar = String.fromCharCode(65535);
-exports.bottomChar = String.fromCharCode(0);
-
-exports.topNumber = Number.POSITIVE_INFINITY;
-exports.bottomNumber = Number.NEGATIVE_INFINITY;
+export const topNumber = Number.POSITIVE_INFINITY;
+export const bottomNumber = Number.NEGATIVE_INFINITY;
diff --git a/src/Data/Eq.js b/src/Data/Eq.js
index 2a2ae3ea..6e8303cb 100644
--- a/src/Data/Eq.js
+++ b/src/Data/Eq.js
@@ -1,18 +1,16 @@
-"use strict";
-
 var refEq = function (r1) {
   return function (r2) {
     return r1 === r2;
   };
 };
 
-exports.eqBooleanImpl = refEq;
-exports.eqIntImpl = refEq;
-exports.eqNumberImpl = refEq;
-exports.eqCharImpl = refEq;
-exports.eqStringImpl = refEq;
+export const eqBooleanImpl = refEq;
+export const eqIntImpl = refEq;
+export const eqNumberImpl = refEq;
+export const eqCharImpl = refEq;
+export const eqStringImpl = refEq;
 
-exports.eqArrayImpl = function (f) {
+export const eqArrayImpl = function (f) {
   return function (xs) {
     return function (ys) {
       if (xs.length !== ys.length) return false;
diff --git a/src/Data/EuclideanRing.js b/src/Data/EuclideanRing.js
index a19fe503..057e6c3e 100644
--- a/src/Data/EuclideanRing.js
+++ b/src/Data/EuclideanRing.js
@@ -1,19 +1,17 @@
-"use strict";
-
-exports.intDegree = function (x) {
+export const intDegree = function (x) {
   return Math.min(Math.abs(x), 2147483647);
 };
 
 // See the Euclidean definition in
 // https://en.m.wikipedia.org/wiki/Modulo_operation.
-exports.intDiv = function (x) {
+export const intDiv = function (x) {
   return function (y) {
     if (y === 0) return 0;
     return y > 0 ? Math.floor(x / y) : -Math.floor(x / -y);
   };
 };
 
-exports.intMod = function (x) {
+export const intMod = function (x) {
   return function (y) {
     if (y === 0) return 0;
     var yy = Math.abs(y);
@@ -21,7 +19,7 @@ exports.intMod = function (x) {
   };
 };
 
-exports.numDiv = function (n1) {
+export const numDiv = function (n1) {
   return function (n2) {
     return n1 / n2;
   };
diff --git a/src/Data/Functor.js b/src/Data/Functor.js
index 73ecc1f5..095e5332 100644
--- a/src/Data/Functor.js
+++ b/src/Data/Functor.js
@@ -1,6 +1,4 @@
-"use strict";
-
-exports.arrayMap = function (f) {
+export const arrayMap = function (f) {
   return function (arr) {
     var l = arr.length;
     var result = new Array(l);
diff --git a/src/Data/HeytingAlgebra.js b/src/Data/HeytingAlgebra.js
index a076fd3f..80990b40 100644
--- a/src/Data/HeytingAlgebra.js
+++ b/src/Data/HeytingAlgebra.js
@@ -1,17 +1,15 @@
-"use strict";
-
-exports.boolConj = function (b1) {
+export const boolConj = function (b1) {
   return function (b2) {
     return b1 && b2;
   };
 };
 
-exports.boolDisj = function (b1) {
+export const boolDisj = function (b1) {
   return function (b2) {
     return b1 || b2;
   };
 };
 
-exports.boolNot = function (b) {
+export const boolNot = function (b) {
   return !b;
 };
diff --git a/src/Data/Ord.js b/src/Data/Ord.js
index 67c1a058..548760e5 100644
--- a/src/Data/Ord.js
+++ b/src/Data/Ord.js
@@ -1,5 +1,3 @@
-"use strict";
-
 var unsafeCompareImpl = function (lt) {
   return function (eq) {
     return function (gt) {
@@ -12,13 +10,13 @@ var unsafeCompareImpl = function (lt) {
   };
 };
 
-exports.ordBooleanImpl = unsafeCompareImpl;
-exports.ordIntImpl = unsafeCompareImpl;
-exports.ordNumberImpl = unsafeCompareImpl;
-exports.ordStringImpl = unsafeCompareImpl;
-exports.ordCharImpl = unsafeCompareImpl;
+export const ordBooleanImpl = unsafeCompareImpl;
+export const ordIntImpl = unsafeCompareImpl;
+export const ordNumberImpl = unsafeCompareImpl;
+export const ordStringImpl = unsafeCompareImpl;
+export const ordCharImpl = unsafeCompareImpl;
 
-exports.ordArrayImpl = function (f) {
+export const ordArrayImpl = function (f) {
   return function (xs) {
     return function (ys) {
       var i = 0;
diff --git a/src/Data/Ring.js b/src/Data/Ring.js
index c6b4a329..cceb66c8 100644
--- a/src/Data/Ring.js
+++ b/src/Data/Ring.js
@@ -1,13 +1,11 @@
-"use strict";
-
-exports.intSub = function (x) {
+export const intSub = function (x) {
   return function (y) {
     /* jshint bitwise: false */
     return x - y | 0;
   };
 };
 
-exports.numSub = function (n1) {
+export const numSub = function (n1) {
   return function (n2) {
     return n1 - n2;
   };
diff --git a/src/Data/Semigroup.js b/src/Data/Semigroup.js
index f1f1abad..1909f557 100644
--- a/src/Data/Semigroup.js
+++ b/src/Data/Semigroup.js
@@ -1,12 +1,10 @@
-"use strict";
-
-exports.concatString = function (s1) {
+export const concatString = function (s1) {
   return function (s2) {
     return s1 + s2;
   };
 };
 
-exports.concatArray = function (xs) {
+export const concatArray = function (xs) {
   return function (ys) {
     if (xs.length === 0) return ys;
     if (ys.length === 0) return xs;
diff --git a/src/Data/Semiring.js b/src/Data/Semiring.js
index 7f38e42e..2d537c18 100644
--- a/src/Data/Semiring.js
+++ b/src/Data/Semiring.js
@@ -1,26 +1,24 @@
-"use strict";
-
-exports.intAdd = function (x) {
+export const intAdd = function (x) {
   return function (y) {
     /* jshint bitwise: false */
     return x + y | 0;
   };
 };
 
-exports.intMul = function (x) {
+export const intMul = function (x) {
   return function (y) {
     /* jshint bitwise: false */
     return x * y | 0;
   };
 };
 
-exports.numAdd = function (n1) {
+export const numAdd = function (n1) {
   return function (n2) {
     return n1 + n2;
   };
 };
 
-exports.numMul = function (n1) {
+export const numMul = function (n1) {
   return function (n2) {
     return n1 * n2;
   };
diff --git a/src/Data/Show.js b/src/Data/Show.js
index 4a85cd66..1f7b4038 100644
--- a/src/Data/Show.js
+++ b/src/Data/Show.js
@@ -1,15 +1,13 @@
-"use strict";
-
-exports.showIntImpl = function (n) {
+export const showIntImpl = function (n) {
   return n.toString();
 };
 
-exports.showNumberImpl = function (n) {
+export const showNumberImpl = function (n) {
   var str = n.toString();
   return isNaN(str + ".0") ? str : str + ".0";
 };
 
-exports.showCharImpl = function (c) {
+export const showCharImpl = function (c) {
   var code = c.charCodeAt(0);
   if (code < 0x20 || code === 0x7F) {
     switch (c) {
@@ -26,7 +24,7 @@ exports.showCharImpl = function (c) {
   return c === "'" || c === "\\" ? "'\\" + c + "'" : "'" + c + "'";
 };
 
-exports.showStringImpl = function (s) {
+export const showStringImpl = function (s) {
   var l = s.length;
   return "\"" + s.replace(
     /[\0-\x1F\x7F"\\]/g, // eslint-disable-line no-control-regex
@@ -50,7 +48,7 @@ exports.showStringImpl = function (s) {
   ) + "\"";
 };
 
-exports.showArrayImpl = function (f) {
+export const showArrayImpl = function (f) {
   return function (xs) {
     var ss = [];
     for (var i = 0, l = xs.length; i < l; i++) {
@@ -60,13 +58,13 @@ exports.showArrayImpl = function (f) {
   };
 };
 
-exports.cons = function (head) {
+export const cons = function (head) {
   return function (tail) {
     return [head].concat(tail);
   };
 };
 
-exports.join = function (separator) {
+export const join = function (separator) {
   return function (xs) {
     return xs.join(separator);
   };
diff --git a/src/Data/Show/Generic.js b/src/Data/Show/Generic.js
index 53338044..59ff681e 100644
--- a/src/Data/Show/Generic.js
+++ b/src/Data/Show/Generic.js
@@ -1,6 +1,4 @@
-"use strict";
-
-exports.intercalate = function (separator) {
+export const intercalate = function (separator) {
   return function (xs) {
     var len = xs.length;
     if (len === 0) return "";
diff --git a/src/Data/Symbol.js b/src/Data/Symbol.js
index b4b6e28f..b2941408 100644
--- a/src/Data/Symbol.js
+++ b/src/Data/Symbol.js
@@ -1,8 +1,6 @@
-"use strict";
-
 // module Data.Symbol
 
-exports.unsafeCoerce = function (arg) {
+export const unsafeCoerce = function (arg) {
   return arg;
 };
 
diff --git a/src/Data/Unit.js b/src/Data/Unit.js
index 379ba659..3eff8c28 100644
--- a/src/Data/Unit.js
+++ b/src/Data/Unit.js
@@ -1,3 +1 @@
-"use strict";
-
-exports.unit = undefined;
+export const unit = undefined;
diff --git a/src/Record/Unsafe.js b/src/Record/Unsafe.js
index c47acf8d..af2d506f 100644
--- a/src/Record/Unsafe.js
+++ b/src/Record/Unsafe.js
@@ -1,18 +1,16 @@
-"use strict";
-
-exports.unsafeHas = function (label) {
+export const unsafeHas = function (label) {
   return function (rec) {
     return {}.hasOwnProperty.call(rec, label);
   };
 };
 
-exports.unsafeGet = function (label) {
+export const unsafeGet = function (label) {
   return function (rec) {
     return rec[label];
   };
 };
 
-exports.unsafeSet = function (label) {
+export const unsafeSet = function (label) {
   return function (value) {
     return function (rec) {
       var copy = {};
@@ -27,7 +25,7 @@ exports.unsafeSet = function (label) {
   };
 };
 
-exports.unsafeDelete = function (label) {
+export const unsafeDelete = function (label) {
   return function (rec) {
     var copy = {};
     for (var key in rec) {
diff --git a/test/Test/Main.js b/test/Test/Main.js
index f3989122..b25cdaca 100644
--- a/test/Test/Main.js
+++ b/test/Test/Main.js
@@ -1,6 +1,4 @@
-"use strict";
-
-exports.testNumberShow = function(showNumber) {
+export function testNumberShow(showNumber) {
   return function() {
     function testAll(cases) {
       cases.forEach(function(c) {
@@ -16,29 +14,29 @@ exports.testNumberShow = function(showNumber) {
     }
 
     testAll([
-        // Within Int range
-        [0.0, "0.0"],
-        [1.0, "1.0"],
-        [-1.0, "-1.0"],
-        [500.0, "500.0"],
+      // Within Int range
+      [0.0, "0.0"],
+      [1.0, "1.0"],
+      [-1.0, "-1.0"],
+      [500.0, "500.0"],
 
-        // Outside Int range
-        [1e10, "10000000000.0"],
-        [1e10 + 0.5, "10000000000.5"],
-        [-1e10, "-10000000000.0"],
-        [-1e10 - 0.5, "-10000000000.5"],
+      // Outside Int range
+      [1e10, "10000000000.0"],
+      [1e10 + 0.5, "10000000000.5"],
+      [-1e10, "-10000000000.0"],
+      [-1e10 - 0.5, "-10000000000.5"],
 
-        // With exponent
-        [1e21, "1e+21"],
-        [1e-21, "1e-21"],
+      // With exponent
+      [1e21, "1e+21"],
+      [1e-21, "1e-21"],
 
-        // With decimal and exponent
-        [1.5e21, "1.5e+21"],
-        [1.5e-10, "1.5e-10"],
+      // With decimal and exponent
+      [1.5e21, "1.5e+21"],
+      [1.5e-10, "1.5e-10"],
 
-        [NaN, "NaN"],
-        [Infinity, "Infinity"],
-        [-Infinity, "-Infinity"],
-      ]);
+      [NaN, "NaN"],
+      [Infinity, "Infinity"],
+      [-Infinity, "-Infinity"],
+    ]);
   };
-};
+}
diff --git a/test/Test/Utils.js b/test/Test/Utils.js
index bea69b25..ae5b410a 100644
--- a/test/Test/Utils.js
+++ b/test/Test/Utils.js
@@ -1,7 +1,5 @@
-"use strict";
-
-exports.throwErr = function(msg) {
+export function throwErr(msg) {
   return function() {
     throw new Error(msg);
   };
-};
+}