Echo Sierra Studio

A freelance web/app/mobile/native development studio. I work with companies and individuals to develop new innovative solutions. I focus on helping sustainable and social initiatives in the field of IT.





I develop cross-platform hybrid/native apps.



I develop webshops, blogs and more.



I develop (native) desktop apps.

Graphic Design

Graphic Design

I create graphic designs.



I will develop your corporate identity (logo, color palette, flyers, etc.).


The easiest way to follow news from your favorite websites, blogs and news sites. Easily search for news on multiple platforms, find feeds on popular websites and more. Also works as a classic RSS/Atom reader.

Open Newsfeeder
Newsfeeder screenshot banner.


ESS Projects.

Home page of Echo Sierra Studio and lander page for all projects (and useless thingies) by ESStudio.

portfolio website

Sem Postma Portfolio

Personal Portfolio.

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Ienze Koekkoek -  image

Ienze Koekkoek - Verstaat

Duurzaam perspectief voor het landelijke gebied.

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Newsfeeder image

Newsfeeder App

Combine your news

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File image

File Share

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Peilingen App

The easiest way to follow news from your favorite websites and blogs and news sites. Easily search for news on multiple platforms, find feeds on popular websites and more. Also works as a classic RSS/Atom reader.

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Bespaar image

Bespaar Maar

Bespaar, Vergelijk en Verdien

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Kadaster Kaart

Kadastrale informatie app

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OV Fiets Website

Web-app/Website version of the “OV Fiets App”

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Fancy image

Fancy Image Tool

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Markdownify - Markdown Viewer

Markdownify is a simple and effective markdown/text file viewer. You can open any file in the markdown format. Markdownify can also view HTML files.

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Ov Fiets App

Monitor the amount of bikes at a rental location

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Salary Comparison

Find out the average salary for almost every job in the world. 

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Public Toilets Amsterdam

Android/Web app

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KSP Part image

KSP Part Catalog

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WT image

WT Directory

Stats on every vehicle in War Thunder

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Numeral image

Numeral Converter Website

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Echochamber Affinity

Check your twitter personality

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Word Finder

Find scrabble words

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Real-time Mindviewer

Mindviewer is a HTML5 web app which allows real-time mindmap building with multiple users in realtime.

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Info image

Info FSNav

Search for airport, fixes, navigation beacons and other information using X-Plane data.

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AHS Style Guide

An inspiration style to ahs characters.

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Atc Manager 2

Atc Manager on the Web

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Youtube Comments Are Evil

Uses Markov Text generation to create fake youtube comments specific to a youtube video.

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Parse image

Parse JSON

Extremely simple json-parsing C library

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ATC Manager

Realistic ATC Control manager.

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Solar System 3D

Newtonian simulator

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Rustplekken Utrecht

Android/Web app

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Laika image

Laika Notes

Note taking app

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Matrix image

Matrix Editor

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HTML2 image


Converts html to javascript instructions.

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Simple Function Plotter image

Simple Function Plotter Website

Website version of the Simple Function Plotter App

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Planetary Factsheet

Nasa’s planetary factsheet in JSON format

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Earth at image

Earth at Night 🌌

Earth by night from space

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JSON2 image


JSON to XML converter utility.

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Bioscopen Nederland

Android/Web app

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Encode Secret image

Encode Secret Image

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Maze image

Maze Solver

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A Star image

A Star Pathfinding

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form- validity

HTML5 constraint validation API wrapper.

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Neural Net Visualizer

For Synaptic.js

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All 3D Models

Other sketchfab creations.

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Boeing 747

Simple Low tri/edge count model.

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Rocks Metallic Pack

PBR textured gaming assets. A curvature map was used to create highlights on the convexity of the model.

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{json}2 csv

CSV2JSON (and back) converter.

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Solitaire image

Solitaire (WIP)

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Save SVG image


Chrome extension.

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Parse image

Parse XML

fast and memory efficient ANSI C xml parsing library.

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Function image

Function Plotter

Expression solver.

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Nosedive Network

Social network. (WIP)

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Boggle image

Boggle Solutions


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Molecule image

Molecule Parser

Dot Net Core C#

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Mouse image

Mouse Mania


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Protected Url

Protect your url by putting it behind a login dialog.

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Air ✈ Control


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Periodic image

Periodic Table

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Design Website

A Simple Design Website.

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Forum image

Forum Example

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Universe image

Universe Creator

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Tappy image

Tappy Turbulance

Another Tappy bird🐦 like game.

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Tappy image

Tappy Plane

A Tappy bird like game.

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Base image

Base Converter

Hex Calculator

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Mars image

Mars Rover

Rusty rover Unity package.

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Color image

Color Adjustor

command line utility

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Mind image

Mind Mapper

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Top Down image

Top Down Defence


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ETL for image

ETL for C#

A WIP testing language

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Atc Chatbot image

Atc Chatbot Air Traffic Control

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