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Hiring portals

Can you still see the trees in the big DAS forest? – Effectively win public hiring portal contracts.

Hiring portals – do it yourself or have it done?

A number of companies and many government organizations have made doing business more accessible for ZZP-ers through public marketplaces, Dynamic Purchasing Systems and hiring portals. Now, as a ZZP-er, it can be quite difficult to find your way around these properly. Basically, the idea is that all these portals are set up in such a way that every ZZP-er can do business directly. But there are still some barriers and opacities that require some dexterity to be successful. What are those challenges?

Finding marketplaces and DASs
Which marketplace, portal or DAS (Dynamic Acquisition System) to choose
Registering or subscribing to a marketplace or DAS
Continuous maintenance (quarterly delivery of correct documents) of a DAS registration
Responding to contracts by means of a tender
Being awarded a contract in terms of content

Contrary to what some commercial parties say, it does not cost you money to do it yourself. it does cost you time. But if you are willing to do it yourself, it is worth considering. You can also choose to do part of it yourself and outsource part. Nothing is for free and for every part of the process that you outsource (from registering with a DAS to preparing and submitting an offer) there is of course a fee.

interview – podcast Edco Wallet – Vincent Spruit

In this episode of our podcast, we talked about the relevance of marketplaces with Edco Wallet, co-founder of OptimaData, who has years of experience hiring through those job marketplaces. He shares his experience with us on the following topics:

  1. What exactly is a marketplace and does it work as hoped?
  2. What is the added value of recruitment agencies for professionals?
  3. Do you have a chance at marketplaces if you don’t meet all the requirements?
  4. What is the impact of hourly rates on marketplaces?
  5. What can you do to increase your chances?
  6. Is it interesting for freelancers to use a marketplace directly?
  7. Tips for freelancers.

What is a Hiring Portal or a DAS?

Most ZZP-ers are familiar with them: marketplaces, Dyanamic Purchasing Systems, Hiring Desks, etc. Many different names for ultimately 1 thing: A central place of 1 client to allow ZZP-ers and other suppliers to do business directly with this client. So what are the differences between these portals?

dynamic purchasing system

A Dynamic Purchasing System (also known as a DAS) is a tool only for organizations subject to procurement requirements. Central and local governments and semi-governments. Mandatory tendering means that one is obliged to publicly publish a work, assignment or product above a certain amount through a tender in order to give the entire market a chance to participate.

An interim assignment usually exceeds this amount due to its duration and hourly rate. The Dynamic Purchasing System has been introduced to prevent the need for a complete tendering procedure for each assignment. After a single tender and assessment for admission to this DAS, the tenderer has access to all published contracts.

This is an attempt to contribute to an open and transparent market where 1-pitters also have the opportunity to do business directly and immediately with this client. Being admitted to a DAS is not yet a concrete assignment. After admission to the DAS of a particular client you will get access to the hiring portal of this client.


A marketplace or hiring portal such as that of GVB, NSIHC Merwede, , etc. publishes all hiring assignments for ZZP-ersor suppliers (agencies with their own staff).

These are interim, temporary assignments to which anyone may respond.In this way, the client in question wants to give everyone the opportunity to do business directly. So basically the company’s job page but for interim assignments.

Access to these marketplaces is quite easy and you automatically get a notification in your mail when you have registered on the marketplace. In most cases, the only document required for registration is an extract from the Chamber of Commerce.


After admission to the DAS, you get access to the hiring portal of this organization. In fact, these hiring portals are nothing but the aforementioned marketplaces of commercial companies. The DAS grants admission and from that moment you have access to the portal or marketplace. A DAS is, so to speak, the gateway. In the portal, then, each published assignment is a mini-tender with knockout criteria and award criteria according to a transparent point system. Well-known (DAS) hiring portals are from Stedin, the Police, Province of Gelderland, municipality of Amsterdam, etc.

Most hiring portals are not owned by the client. A large group of commercial parties offer complete platforms for companies and government contracting agencies such as CTM solutions, Negometrix, Inhuurdesk (Staffing MS) and PoolZ. There, so to speak, is the first revenue model for the flex market in this chain.

Characteristics for hiring portals (DAS or no DAS):

  • advance registration required (with a DAS slightly more extensive);
  • free access/responses;
  • everyone has equal opportunity;
  • client is known;
  • procedure and award criteria known;
  • contacts are entirely digital;
  • winner is published.

Overzicht marktplaatsen, inhuurportalen en DAS

In the multitude of marketplaces and Dynamic Purchasing Systems, it can be difficult to see the trees for the forest. Fortunately, there are a number of overviews that can help you get started finding them:



  • Overview by with choice of self-subscription or with help of freep at 10% margin through hiring-government
  • Overview by Transparent Brokers and Das-Service with services against fee or margin through hiring card

By the way, it can pay off by registering for free on Tenderned. All newly created or established DAS for an organization is published here. This way you keep in touch with any new interesting clients.

Subscribe DAS

You’ve seen an interesting client with a DAS. Registering for a DAS is quite a chore. You have to submit all kinds of official statements, fill out forms and provide documents. Such as a GVA (behavioral statement on tendering, to be obtained from the Justice Department), statement of payment behavior (to be obtained from the tax office) but also your CoC extract and insurance papers. At first glance it seems very complex. Read carefully and if you follow the guide step by step you will get there.

Ook in deze fase van de keten zijn inmiddels commerciele partijen opgestaan zoals Tender Services Group en DAS-Service (gekoppeld aan die tegen een vergoeding per DAS je helpen met inschrijven. Dat is het tweede verdienmodel in deze keten.

Also in this phase of the chain, commercial parties have now emerged such as  Tender Services Group en DAS-Service (linked to that, for a fee per DAS, help you tender. That is the second revenue model in this chain.

Finding and selecting assignments

Now that you are registered and / or enrolled in 1 or more Dynamic Purchasing Systems it is a matter of finding the right assignments. Once you are connected you can usually specify per hiring portal what type of assignments (area of expertise) you want to receive. In our ICT sector, this is still very broad. You will receive all ICT requests from each hiring portal you have signed up for and allowed. That’s option 1. Just keep an eye on your mailbox and of course pay more active attention in a period when you become available again.

Option 2 is to use a number of overviews such as or the Transparante Broker. I Unlike, the other 2 are commercial and that is, so to speak, the third revenue model in this chain.

Pay close attention to whether the stated independence and transparency of different providers is actually happening. Some seemingly independent overviews are born from a commercial point of view and linked together. Of course, in many cases it is a good service and a free choice to do business with. You may wonder if it is smart to choose 1 party on 2 or 3 revenue models in the chain (who ultimately eats into your rate).

Services OptimaData – For data professionals

We are already subscribed to all relevant hiring portals and Dynamic Purchasing Systems. We bring together the most interesting Data related assignments in 1 place. We are transparent about the client and all details of the assignment, including the price.

This gives you the free choice to submit a quote yourself through the relevant hiring portal. You can also choose to let us guide you through this and let us do the work. You are strong in data issues, we are handy with hiring portals. And last but not least: we are data experts ourselves.

We know what it’s all about. Other providers and brokers who help you submit on marketplaces are generalist and have no direct content knowledge regarding the job.

For example, is ETL a device, a tool or a method, structural misspelling of the largest open source database in the world (Postgress instead of PostgreSQL) and certification questions about open source products are unfortunately striking examples.

Because we have good knowledge of the content, we are able to strike the right tone and chord in the quotation. Because that is exactly what we do. We turn your CV into a custom quote that touches on what the assignment requires. Provided, of course, that you are capable of carrying out the assignment. Finally,

it is also an added value to know how the various hiring portals work around selection. Many people do not know that much of the initial selection is fully automated (with tools like textkernel).

Er is in de eerste fase niemand die jouw CV of Offerte echt gaat lezen. Er is dus ook geen ruimte voor nuance. De inhurende manager krijgt alleen de CV’s van die professionals die door inkoop zijn geselecteerd. Zonder kennis van de inhoud. Natuurlijk kun je ervoor kiezen zelf je CV om te bouwen en in een offerte specifiek te richten op die ene opdracht. Maar het kan lonen om je daarbij te laten adviseren door een collega data expert, zoals bijvoorbeeld OptimaData.

  • Centraal overzicht interessante Data opdrachten
  • Eerlijk en transparant over de opdrachtgever
  • Vrije keuze – zelf doen of laten doen
  • Meedenken op inhoud door data experts
  • Kennis van selectie-methoden
  • Geen exclusiviteit, ook niet na voordracht
  • Transparant proces
  • Efficiente voorbereiding offerte
  • Meetbaar succesvolle maatwerk offertes
  • Transparante prijs

In 6 steps to your new assignment

1 React

You can respond directly to any assignment. Only CV and short motivation is sufficient

2 Selection

After the published closing date, we will make a choice as to which candidate is the best fit. You will also be notified no later than the closing date if we have made another choice. This also gives you the opportunity to submit an offer to this client via another route than OptimaData.

3 selected

If we have selected you, we will give you some homework to provide input for the custom offer in addition to the CV. We often schedule a joint moment for that as well (mentioned in the assignment). Then we also spar about the price we are going to submit, in other words, how do we make the most of it.

4 Submission of offer

Once you turn in your homework, we get to work. Sometimes we ask you to add some more detail. Once everything is in order we submit the quotation. We do not ask for exclusivity, you can still take on other assignments or submit quotes elsewhere.

5 Interview invitation

The goal is to bring you to the table. As soon as we hear that you can go for an interview, we will let you know immediately and can advise you on soft skills and competencies that are often explored during such an interview. We also have a tried and tested method to prepare you for the interview. It’s not something you do every day, so it’s good to remember what to look out for and how to present yourself successfully.

6 Award

If the assignment is awarded to you, we’ll celebrate! And of course we will start the onboarding, set up contracts and make sure you can have a soft landing in your new assignment.

Personal contact

If you have any doubts or a question, just want to spar, you can always call us. With us in this process not so much is automated, we don’t do bulk and huge volumes. We know the content of every assignment. Personal attention and really being seen are very important to us. Do not hesitate to contact us.