diff --git a/doc/faq.md b/doc/faq.md
index 73ae94a4d3..2c9bdc0c84 100644
--- a/doc/faq.md
+++ b/doc/faq.md
@@ -77,7 +77,7 @@ var map = new ol.Map({
 var swissProjection = new ol.proj.Projection({
   code: 'EPSG:21781',
   // The extent is used to determine zoom level 0. Recommended values for a
-  // projection's validity extent can be found at http://epsg.io/.
+  // projection's validity extent can be found at https://epsg.io/.
   extent: [485869.5728, 76443.1884, 837076.5648, 299941.7864],
   units: 'm'
 });
@@ -94,7 +94,7 @@ var map = new ol.Map({
 ```
 
 We recommend to lookup parameters of your projection (like the validity extent)
-over at [epsg.io](http://epsg.io/).
+over at [epsg.io](https://epsg.io/).
 
 
 ## Why is my map centered on the gulf of guinea (or africa, the ocean, null-island)?
diff --git a/doc/tutorials/raster-reprojection.md b/doc/tutorials/raster-reprojection.md
index 8dbe9a4b05..1ef0a0e847 100644
--- a/doc/tutorials/raster-reprojection.md
+++ b/doc/tutorials/raster-reprojection.md
@@ -10,7 +10,7 @@ Transformation of the map projections of the image happens directly in a web bro
 The view in any Proj4js supported coordinate reference system is possible and previously incompatible layers can now be combined and overlaid.
 
 # Usage
-The API usage is very simple. Just specify proper projection (using [EPSG](http://epsg.io) code) on `ol.View`:
+The API usage is very simple. Just specify proper projection (using [EPSG](https://epsg.io) code) on `ol.View`:
 ``` javascript
 var map = new ol.Map({
   target: 'map',
@@ -42,7 +42,7 @@ If a source (based on `ol.source.TileImage` or `ol.source.Image`) has a projecti
 
 ### Custom projection
 The easiest way to use a custom projection is to add the [Proj4js](http://proj4js.org/) library to your project and then define the projection using a proj4 definition string.
-Following example shows definition of a [British National Grid](http://epsg.io/27700):
+Following example shows definition of a [British National Grid](https://epsg.io/27700):
 
 ``` html
 <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.3.14/proj4.js"></script>
diff --git a/examples/reprojection-by-code.html b/examples/reprojection-by-code.html
index 6eb1a1bd69..a6a4f08ae1 100644
--- a/examples/reprojection-by-code.html
+++ b/examples/reprojection-by-code.html
@@ -5,7 +5,7 @@ shortdesc: Demonstrates client-side raster reprojection of OSM to arbitrary proj
 docs: >
   This example shows client-side raster reprojection capabilities from
   OSM (EPSG:3857) to arbitrary projection by searching
-  in <a href="http://epsg.io/">EPSG.io</a> database.
+  in <a href="https://epsg.io/">EPSG.io</a> database.
 tags: "reprojection, projection, proj4js, epsg.io"
 resources:
   - https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.3.15/proj4.js
diff --git a/examples/reprojection-by-code.js b/examples/reprojection-by-code.js
index d78cd8302d..d763cc6f41 100644
--- a/examples/reprojection-by-code.js
+++ b/examples/reprojection-by-code.js
@@ -63,7 +63,7 @@ function setProjection(code, name, proj4def, bbox) {
 
 function search(query) {
   resultSpan.innerHTML = 'Searching ...';
-  fetch('http://epsg.io/?format=json&q=' + query).then(function(response) {
+  fetch('https://epsg.io/?format=json&q=' + query).then(function(response) {
     return response.json();
   }).then(function(json) {
     var results = json['results'];
diff --git a/examples/wms-custom-proj.js b/examples/wms-custom-proj.js
index d973b1c206..21daf44a2e 100644
--- a/examples/wms-custom-proj.js
+++ b/examples/wms-custom-proj.js
@@ -16,7 +16,7 @@ goog.require('ol.source.TileWMS');
 var projection = new ol.proj.Projection({
   code: 'EPSG:21781',
   // The extent is used to determine zoom level 0. Recommended values for a
-  // projection's validity extent can be found at http://epsg.io/.
+  // projection's validity extent can be found at https://epsg.io/.
   extent: [485869.5728, 76443.1884, 837076.5648, 299941.7864],
   units: 'm'
 });
diff --git a/examples/wms-image-custom-proj.js b/examples/wms-image-custom-proj.js
index ddfe27cae9..900e6fb1f5 100644
--- a/examples/wms-image-custom-proj.js
+++ b/examples/wms-image-custom-proj.js
@@ -17,7 +17,7 @@ goog.require('ol.source.ImageWMS');
 //
 // Note that we are setting the projection's extent here, which is used to
 // determine the view resolution for zoom level 0. Recommended values for a
-// projection's validity extent can be found at http://epsg.io/.
+// projection's validity extent can be found at https://epsg.io/.
 //
 // If you use Proj4js only to transform coordinates, you don't even need to
 // create an ol.proj.Projection instance. ol.proj.get() will take care of it
diff --git a/src/ol/proj/index.jsdoc b/src/ol/proj/index.jsdoc
index d188ef7cb8..624cc6e0dd 100644
--- a/src/ol/proj/index.jsdoc
+++ b/src/ol/proj/index.jsdoc
@@ -19,7 +19,7 @@
  * Proj4js, or create a custom build to support those projections you need; see
  * the Proj4js website for how to do this. You also need the Proj4js definitions
  * for the required projections. These definitions can be obtained from
- * {@link http://epsg.io/}, and are a JS function, so can be loaded in a script
+ * {@link https://epsg.io/}, and are a JS function, so can be loaded in a script
  * tag (as in the examples) or pasted into your application.
  * The first time there is a request for a projection, either with a
  * {@link ol.proj.projectionLike} or directly with {@link ol.proj.get}, the