diff --git a/CHANGELOG.md b/CHANGELOG.md
index ffecdbd2..2508b330 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## Next version
 
+- Remove some deps to Belt, Pervasives and Js. https://github.com/rescript-association/rescript-core/pull/226/commits
+
 ## 1.3.0
 
 This version requires ReScript `>=11.1.0-rc.6`.
diff --git a/src/Core__Array.mjs b/src/Core__Array.mjs
index f33b3840..d29db492 100644
--- a/src/Core__Array.mjs
+++ b/src/Core__Array.mjs
@@ -1,6 +1,5 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
-import * as Js_math from "rescript/lib/es6/js_math.js";
 import * as Caml_option from "rescript/lib/es6/caml_option.js";
 
 function make(length, x) {
@@ -113,10 +112,14 @@ function swapUnsafe(xs, i, j) {
   xs[j] = tmp;
 }
 
+function random_int(min, max) {
+  return (Math.floor(Math.random() * (max - min | 0)) | 0) + min | 0;
+}
+
 function shuffle(xs) {
   var len = xs.length;
   for(var i = 0; i < len; ++i){
-    swapUnsafe(xs, i, Js_math.random_int(i, len));
+    swapUnsafe(xs, i, random_int(i, len));
   }
 }
 
diff --git a/src/Core__Array.res b/src/Core__Array.res
index a80a8e10..15199dd0 100644
--- a/src/Core__Array.res
+++ b/src/Core__Array.res
@@ -203,10 +203,20 @@ let swapUnsafe = (xs, i, j) => {
   setUnsafe(xs, j, tmp)
 }
 
+module M = {
+  @val external floor: float => float = "Math.floor"
+  @val external random: unit => float = "Math.random"
+  external fromFloat: float => int = "%intoffloat"
+  external toFloat: int => float = "%identity"
+
+  let random_int: (int, int) => int = (min, max) =>
+    floor(random() *. toFloat(max - min))->fromFloat + min
+}
+
 let shuffle = xs => {
   let len = length(xs)
   for i in 0 to len - 1 {
-    swapUnsafe(xs, i, Js.Math.random_int(i, len)) /* [i,len) */
+    swapUnsafe(xs, i, M.random_int(i, len)) /* [i,len) */
   }
 }
 
diff --git a/src/Core__Int.mjs b/src/Core__Int.mjs
index 6d921bd5..96f246a0 100644
--- a/src/Core__Int.mjs
+++ b/src/Core__Int.mjs
@@ -1,7 +1,6 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
 import * as Core__Array from "./Core__Array.mjs";
-import * as PervasivesU from "rescript/lib/es6/pervasivesU.js";
 
 function equal(a, b) {
   return a === b;
@@ -26,6 +25,14 @@ function fromString(x, radix) {
   }
 }
 
+function abs(x) {
+  if (x >= 0) {
+    return x;
+  } else {
+    return -x | 0;
+  }
+}
+
 function range(start, end, optionsOpt) {
   var options = optionsOpt !== undefined ? optionsOpt : ({});
   var isInverted = start > end;
@@ -51,7 +58,7 @@ function range(start, end, optionsOpt) {
   } else {
     var range$1 = isInverted ? start - end | 0 : end - start | 0;
     var range$2 = options.inclusive === true ? range$1 + 1 | 0 : range$1;
-    length = Math.ceil(range$2 / PervasivesU.abs(step)) | 0;
+    length = Math.ceil(range$2 / abs(step)) | 0;
   }
   return Core__Array.fromInitializer(length, (function (i) {
                 return start + Math.imul(i, step) | 0;
diff --git a/src/Core__Int.res b/src/Core__Int.res
index 34acdf36..94d57c62 100644
--- a/src/Core__Int.res
+++ b/src/Core__Int.res
@@ -48,6 +48,13 @@ external mod: (int, int) => int = "%modint"
 
 type rangeOptions = {step?: int, inclusive?: bool}
 
+let abs = x =>
+  if x >= 0 {
+    x
+  } else {
+    -x
+  }
+
 let range = (start, end, ~options: rangeOptions={}) => {
   let isInverted = start > end
 
diff --git a/src/Core__List.mjs b/src/Core__List.mjs
index dd1d1e0b..0d6cd1d8 100644
--- a/src/Core__List.mjs
+++ b/src/Core__List.mjs
@@ -1,6 +1,5 @@
 // Generated by ReScript, PLEASE EDIT WITH CARE
 
-import * as Belt_Array from "rescript/lib/es6/belt_Array.js";
 import * as Caml_option from "rescript/lib/es6/caml_option.js";
 import * as Core__Array from "./Core__Array.mjs";
 
@@ -794,7 +793,12 @@ function reduceReverse(l, acc, f) {
   if (len < 1000) {
     return reduceReverseUnsafe(l, acc, f);
   } else {
-    return Belt_Array.reduceReverseU(toArray(l), acc, f);
+    var a = toArray(l);
+    var r = acc;
+    for(var i = a.length - 1 | 0; i >= 0; --i){
+      r = f(r, a[i]);
+    }
+    return r;
   }
 }
 
@@ -888,7 +892,14 @@ function reduceReverse2(l1, l2, acc, f) {
   if (len < 1000) {
     return reduceReverse2Unsafe(l1, l2, acc, f);
   } else {
-    return Belt_Array.reduceReverse2U(toArray(l1), toArray(l2), acc, f);
+    var a = toArray(l1);
+    var b = toArray(l2);
+    var r = acc;
+    var len$1 = a.length < b.length ? a.length : b.length;
+    for(var i = len$1 - 1 | 0; i >= 0; --i){
+      r = f(r, a[i], b[i]);
+    }
+    return r;
   }
 }
 
diff --git a/src/Core__List.res b/src/Core__List.res
index b5cb4923..88fae3ab 100644
--- a/src/Core__List.res
+++ b/src/Core__List.res
@@ -63,12 +63,26 @@
 
 type t<'a> = list<'a>
 
-// TODO: This module should be inlined eventually, if we end up removing Belt
-// from the compiler.
 module A = {
-  let makeUninitializedUnsafe = Belt_Array.makeUninitializedUnsafe
-  let reduceReverseU = Belt_Array.reduceReverseU
-  let reduceReverse2U = Belt_Array.reduceReverse2U
+  @new external makeUninitializedUnsafe: int => array<'a> = "Array"
+  external min: ('a, 'a) => 'a = "%bs_min"
+
+  let reduceReverseU = (a, x, f) => {
+    let r = ref(x)
+    for i in Core__Array.length(a) - 1 downto 0 {
+      r.contents = f(r.contents, Core__Array.getUnsafe(a, i))
+    }
+    r.contents
+  }
+
+  let reduceReverse2U = (a, b, x, f) => {
+    let r = ref(x)
+    let len = min(Core__Array.length(a), Core__Array.length(b))
+    for i in len - 1 downto 0 {
+      r.contents = f(r.contents, Core__Array.getUnsafe(a, i), Core__Array.getUnsafe(b, i))
+    }
+    r.contents
+  }
 }
 
 external mutableCell: ('a, t<'a>) => t<'a> = "#makemutablelist"