Jelle De Laender


Jelle De Laender

Jelle founded Coding Mammoth in 2007, to work on his own ideas and projects like Semonto, QuickScale, MijnLijn and more. He also helps other companies to reach their objectives and goals, like Sketch. In his spare time, he is also interested in security research, AWS cloud hosting, macro photography, running, 3D printing and more. Get in touch with him!

WordPress monitoring in Semonto


Our WordPress plugin is live!

As of today, you can install the Semonto plugin to monitor your WordPress website and configure server health tests from within the WordPress dashboard.

Jelle De Laender - 2 May 2024

Office with cron job monitoring


Bye bye PulseChecks, Hello Cron job monitoring

Do you know our Pulsecheck feature?

Jelle De Laender - 23 April 2024

Domain status in Semonto on a desktop background.


New feature: Domain Monitoring

We have recently released a new feature in Semonto: domain monitoring. In this article, we explain what domain monitoring is, why you need it and how it works. Let’s dive in!

Jelle De Laender - 21 March 2024

A screenshot of our new pricing page in a desktop mock up


We changed our pricing. Here’s what’s new.

No, this is not another announcement by a SaaS tool to announce a pricing increase. In fact, most customers will notice a slight price reduction. Find out why we changed our pricing and what it means for your subscription.

Jelle De Laender - 12 February 2024

A PandaPanda team meeting

Use Case

PandaPanda: “Our products are built to last. With Semonto, we can prove it.”

These days, creating beautiful websites and apps is not enough. You also have to keep them up and running. We asked digital agency PandaPanda how they use monitoring to make sure that their products stand the test of time.

Jelle De Laender - 17 January 2024

Illustration of Semonto with a computer terminal with fireworks background.

Life at Semonto

Semonto's 2023 wrap-up

In the last week of 2023, we love to take a moment to look back at everything that happened this year.

Jelle De Laender - 29 December 2023

A screenshot of Server health status in Semonto


NEW in Semonto: Server Health Monitoring

We've just added Server Health Monitoring as a standalone feature in Semonto! In short: it is now easier than ever to test your server's health independently of your website monitoring.

Jelle De Laender - 3 October 2023

Screenshot of certificate validation in Semonto


Get notified of all SSL certificate changes

We don’t need to tell you how important it is for your website health to have a valid SSL certificate. That is why, by default, Semonto lets you know when a certificate is in trouble or about to expire. But today, we are taking it one step further.

Jelle De Laender - 13 July 2023

Old man in a forest

Use Case

Semonto use case: GPS tracker Mindme locates people in need

What would you do if you needed help and no one was around? That question led to the creation of Mindme - a UK-based company producing wearable personal alarm devices that allow users to get help quickly when they are alone. In this interview, co-owner Simon Wolf explains why he uses Semonto.

Jelle De Laender - 17 May 2023

Illustration of a 404 page on a desktop background

Use Case

Should I use Google Search Console to find broken links on my website?

Can you use Google Search Console to find broken links on your website? Yes and no. In this article, we explain why Google Search Console is not sufficient to keep your website free from broken links and what you should do instead.

Jelle De Laender - 22 March 2023

Screenshot of Semonto on a desktop background

Tips and Tricks

How to create an escalation process in Semonto

Did you know that Semonto can help you to automate your incident escalation? In this article, we show you how.

Jelle De Laender - 23 January 2023

Coding Mammoth office

Life at Semonto

Semonto's 2022 wrap-up

Time flies, it’s already 2023. Time to look back at 2022 and all the things that happened at Semonto.

Jelle De Laender - 02 January 2023

Illustration of an error page and a mobile phone with push notifications


New Feature: Allowed Downtime

In Semonto, you can define how long an issue is allowed to persist before you want to be alerted. You can also create an escalation system, so that different people get notified depending on the duration of the issue.

Jelle De Laender - 23 December 2022

Screenshot of semonto on desktop background

Tips and Tricks

What is web hosting, and why should I care?

What is hosting? Who is responsible for your hosting? And how can you measure the quality? In this article, we answer all hosting-related questions.

Jelle De Laender - 20 October 2022

Screenshot of broken link history on desktop background


NEW: Broken link timeline

We have added a chart that shows you the evolution of the number of broken links on your website in the last 30 days.

Jelle De Laender - 14 October 2022

Entrepreneur holding a mobile phone

Tips and Tricks

HTTPS and TLS/SSL Monitoring Explained

Attracting new clients is more important than ever. So companies invest more in sales, SEO and marketing. But what if the visitors you attract leave your website immediately? Find out what you should be checking instead.

Jelle De Laender - 19 August 2022

A website audit report from Semonto


NEW: How to create a website audit report (beta)

What if you could perform a website audit and receive the performance results in a PDF report? In this article, we'll show you how it's done.

Jelle De Laender - 17 June 2022

Screenshot of the first website in line mode at

Tips and Tricks

The World Wide Web is 30 years old

The World Wide Web is 30 years old today and has become indispensable by most people.

Jelle De Laender - 12 March 2019

text when will you return on building

Tips and Tricks

Why you should care about your website’s uptime

Your uptime percentage indicates how long your website was available without any interruption. Find out in this article why you should care.

Jelle De Laender - modified 5 May 2022

Screenshot of search function in Semonto


New Search Bar: Find Anything Within Semonto

We have added a search function to the top navigation. This way, you can find anything in Semonto, from a URL to a phone number. Give it a try!

Jelle De Laender - 29 December 2021

Computer screen with pricing page mockup


New: Improved Subscription Model

As you might have noticed, we are continually working on Semonto to give you the best possible experience. Today, we are proud to announce our latest improvement: our new subscription model.

Jelle De Laender - 10 November 2020

Womens hands holding a mobile phone showning a chart

Tips and Tricks

9 ways to prepare your website for Black Friday and Cyber Monday

Can your website handle the Black Friday and Cyber Monday madness? With this checklist, your website is ready for a possible peak in traffic.

Jelle De Laender - modified 11 November 2022

Mockup of a desktop with Slack


NEW: Semonto notifications in Slack

As of today, you can receive Semonto notifications straight in your favourite Slack channel.

Jelle De Laender - 9 March 2022

Mockup of notification in Semonto on a colourful background


New Feature: Marking Notification Settings as Default

In Semonto, you can now choose how you want to be alerted of detected issues, and then reuse those settings by marking them as default.

Jelle De Laender - 20 December 2021

A screenshot of semonto on a desktop

Use Case

5 Reasons Web Developers Use Semonto to Find Broken Links

Semonto started out as an uptime monitoring tool. But, at the request of the web developers in our community, we recently added broken link monitoring to our features. Find out why this matters to web developers and why Semonto is better than other broken link checkers out there.

Jelle De Laender - 14 October 2021

Hand on laptop keyboard

Use Case

3 Monitoring Hacks for Website developers

We asked Ivo, a web developer who frequently uses Semonto, to explain how he monitors the websites he builds for his clients and whether he can share some helpful monitoring hacks for other website developers like himself.

Jelle De Laender - 19 May 2021

Screenshot of Semonto's public tool

Tips and Tricks

4 Free Tools to Check The Health of Your Website

Every website will run pretty smoothly for the first year or so. But just like a car, it will start to fall apart over time if you do not give it a regular check-up. At Coding Mammoth, we have created 4 free tools to check the health of your website. In the following sections, we will explain what these checks are, why they are important and how you can use them for free.

Jelle De Laender - 19 April 2021

MijnLijn artwork

Use Case

Monitoring MijnLijn API and servers

Semonto is great for monitoring websites and webshops' availability and reachability and for locating mixed content and broken links. But Semonto can also be used to deeply monitor custom web applications like MijnLijn.

Jelle De Laender - 7 April 2021

Coding Mammoth office

Life at Semonto

Semonto's 2020 wrap-up

2020 was a weird and unique year for everyone, for sure. The COVID-19 pandemic affected everyone in one way or another, including us. Luckily, at Coding Mammoth, the company behind Semonto, we were already working fully remotely and distributed, and our sector was not that affected. Still, we felt the impact of the COVID-19 pandemic.

Jelle De Laender - 21 December 2020

man receiving voice message


New in Semonto: Voice Message Notifications

We have added a new alert option to Semonto. You can now get notified by voice message whenever something is wrong with your website or server.

Jelle De Laender - 2 November 2020

Screenshot of the new Android app


NEW! Semonto app now available for Android

Good news for Android users! Our Semonto uptime notification app is now available in Google Play for you to download.

Jelle De Laender - 19 October 2020

Screenshot of a status page

Tips and Tricks

How to monitor a server that is not publicly accessible

Monitoring a server that is not publicly accessible? Easy! Instead of calling your server, your server pings us. In this article, we explain exactly how that works

Jelle De Laender - 25 August 2020

Illustrative image of Semonto on a laptop


HTTPS, SSL & TLS Monitoring

Securing your website via HTTPS is a must. It increases the security and trust level for your customers and website visitors. But because HTTPS uses SSL certificates, your website becomes more sensitive to configuration errors that can bring your entire site down. With Semonto HTTPS monitoring, you will never miss an expired or revoked certificate or a broken SSL chain again.

Jelle De Laender - 23 June 2020

Illustrative image of lego figure with a broken computer

Tips and Tricks

Does your website need HTTPS?

What is HTTPS and why is it important? A lot of people think that HTTPS only adds value if your website is a bank tool or if it contains sensitive data. Don't be fooled. HTTPS should be enabled on all websites. That means that you need it, too. Why? Read all about it in this article.

Jelle De Laender - 31 March 2020

Illustratie van een laptop met semonto en een nieuws site

Tips and Tricks

Wij waken gratis over je website tot de coronacrisis voorbij is

Om ondernemingen die getroffen zijn door de coronacrisis te ondersteunen bieden we Semonto gratis 4 maanden aan. We houden de webshop nauwlettend in de gaten en verwittigen bij de eerste problemen, zodat de ondernemer zich kan focussen op zijn bedrijf.

Jelle De Laender - 24 March 2020

Illustrative image of a laptop with semonto and a news site

Tips and Tricks

We will watch your website for free while you are fighting the corona crisis

We want to support other companies that are affected by the coronacrisis by offering Semonto for free for 4 months. Together we are stronger.

Jelle De Laender - 24 March 2020

Illustrative image of lego figure with a broken computer

Tips and Tricks

What to do if your website is down

Is your website down? There are some things you can do to figure out what is going on. In this blog, we will take you through the process step by step.

Jelle De Laender - 10 December 2019

Semonto logo on a light background

Life at Semonto

Digital Marketer & Copywriter Wanted

Are you a native Dutch speaking freelancer, your English is fluent and you have an affinity with ICT? You might be the Copywriter/Digital Marketeer we are looking for to apply your expertise for our Semonto service.

Jelle De Laender - 13 September 2019

The 12★apps logo on a background of the universe

Tips and Tricks

12★apps Christmas Special

Semonto takes part in the 12★apps Christmas Special.

Jelle De Laender - 26 December 2018

Relaxed person with a laptop and Black Friday / Cyber Monday discount offer

Tips and Tricks

Black Friday / Cyber Monday!

Black Friday / Cyber Monday! 20% discount on until 29 November 2018!

Jelle De Laender - 22 November 2018

No credit card required. Cancel anytime. No automatic renewal after the trial.