Your candidates answer a WhatsApp message within minutes, while your email sits unopened for a day. So your recruiters started using WhatsApp from their own phones, and now you have a channel that works and sits entirely outside your systems. This article shows how to run WhatsApp follow-up as a process: which response time counts, when you outgrow the Business app, which messages get a reply, and how to handle consent, retention and logging.

Why WhatsApp beats email and voicemail

The candidates most staffing and secondment agencies depend on are standing on a shop floor or working a shift during the day. They have no work mailbox, they do not pick up an unknown mobile number and they do not listen to voicemail. They do read a WhatsApp message, often within a few minutes, and they can reply between tasks without their supervisor watching.

The window that counts is not twenty-four hours. It is the time between the application and the moment another agency calls. Pick a norm and write it down: during office hours a personal message within fifteen minutes, outside office hours an automatic acknowledgement plus a personal message in the first hour of the next working day. That norm is your agency's choice, not an industry figure. Do measure it, alongside your other funnel KPIs.

Business app or Business Platform: what you actually need

The WhatsApp Business app is the free version from the app store. One number, one main device with a few linked devices, quick replies, labels and an away message. For a branch with one or two recruiters on a single agency number that is enough, and it beats four personal phones.

The WhatsApp Business Platform, usually just called the API, is not an app but a connection through a provider. You pay per conversation, your number no longer lives on a handset, and you get what an agency needs: multiple recruiters in one inbox, permissions per role, approved templates for starting a conversation, and a webhook into your ATS.

When you outgrow the Business app

  • More than three recruiters work the same number, or several branches share one brand.
  • You want conversations to start automatically from your ATS, right after an application arrives.
  • You want conversations in the candidate record without copying and pasting.
  • You want to report on response time and reply rate per message type.
  • You want a departing recruiter to take no history out the door.

One rule applies to both versions: once a candidate messages you, you can write back freely for twenty-four hours. After that you can only reopen the conversation with an approved template. That is why agencies wanting to reactivate old candidates usually end up on the platform.

The real problem: recruiters on their own phones

Most agencies did not decide to move to WhatsApp, it happened to them. One recruiter messaged one candidate because it was faster, it worked, and two years later your most important candidate channel runs across four personal phones. That is not a flaw in your team, it is a gap in your setup.

  • The history walks out the door. When the recruiter leaves, the conversations leave too, including every commitment made in them.
  • Nothing lands in the ATS. A colleague approaches someone rejected three weeks ago or just placed.
  • There is no oversight. What was promised about rates, hours or contract type cannot be retrieved when someone complains.
  • The candidate has a person's number, not your agency's. Sickness or resignation and it goes silent.

Do the math. Assume: 120 applications a month, four recruiters, an average of six messages per candidate. That is over 700 messages a month holding candidate information stored nowhere central. Note: these are assumptions to show the calculation, not industry figures. Put in your own numbers.

“A channel you cannot hand over is not a channel, it is a personal favour from your recruiter.”

The fix is boring and it works: one business number per team or branch, not per person. Recruiters work in a shared inbox, and when someone leaves you put a colleague on the same conversations. Personal phones are explicitly ruled out in your working instructions.

Messages that get a reply

A message that reads like a mailing gets no reply. Four rules of thumb: say your name and what the candidate applied for, stay under three lines, ask one question with two concrete options, and put no link in the first message.

Four messages you can copy

  1. First contact, within fifteen minutes: Hi Ryan, you just applied for the forklift driver role in Tilburg. I am Sanne from [agency name]. Can I call you today between 4 and 6pm, or does tomorrow morning work better?
  2. Reminder after a day of silence: Hi Ryan, no reply yet, so I will try once. The client wants to meet someone this week. Just say yes or no, then I know whether to take you off the list.
  3. Confirmation and no-show prevention: Hi Ryan, we are set: Thursday 10:00 at Stationsweg 12 in Tilburg. Bring your ID. Send a yes back here so I know it is going ahead.
  4. Reactivation via template: Hi Ryan, last year you applied with us for logistics work. A permanent shift is now free in Tilburg, 38 hours. Interested, yes or no? Reply stop if you would rather not hear from us.

What does not work: Dear candidate, thank you for your application. We have received your details in good order and will be in touch as soon as possible. That is an acknowledgement disguised as a conversation, and it burns your twenty-four-hour window.

Consent: handle it on the application form

Someone who responds to a vacancy and leaves a mobile number expects contact about that vacancy. If you want to message the same candidate months later about different work, you want demonstrable consent. Put a separate, not pre-ticked box on the form: Yes, you may call me and contact me via WhatsApp about this and comparable vacancies.

Then store what you need to show later. Four fields are enough.

  • whatsapp_consent: yes or no, plus date and time.
  • whatsapp_source: which form, which vacancy, which version of the wording.
  • whatsapp_number: a separate field, not reused from an old import.
  • whatsapp_optout: the date someone sent stop or opted out verbally.

Treat an opt-out as a hard stop, even when it only exists in the chat. Agree that every recruiter records it in the ATS the same working day and that opted-out candidates automatically drop out of reactivation lists.

Retention, deletion and what you never do in chat

A WhatsApp conversation with a candidate is processing of personal data, the same as a CV in your ATS. Under GDPR that mainly means: keep it no longer than you need, record why you keep it, and be able to produce or delete it when someone asks. This is not legal advice, have your retention policy reviewed by your own adviser. In practice, this is the checklist.

  • Pick one retention period for candidate data and make the chats follow it.
  • Sign a data processing agreement with your provider before conversations run through their platform.
  • Never ask for a national ID number, ID photos or health details in the chat. That goes through your secure onboarding.
  • Record who may read conversations. An inbox where everyone sees everything is a choice, not a given.
  • Make sure you can export or delete a conversation on request, including on a personal phone.

From chat to candidate record

A WhatsApp channel that never reaches your ATS only relocates your problem. Through the platform you attach incoming and outgoing messages to the candidate record with a webhook, so every conversation lands as a note or activity. Same exercise as connecting your ATS and CRM: decide which system holds the truth and have everything else write to it.

If you have no connection yet, work with a rule you can check: after every conversation the recruiter records the outcome, the next step with a date and the status change in the ATS that same day. You do not need every message, you need the decision. After that you can measure response time per vacancy, reply rate per message type, and the share of conversations that leads to an intake.

Conclusion

For most staffing audiences WhatsApp is the fastest channel you have, which is exactly why it cannot stay on four personal phones. Set up one agency number, agree a response time and measure it, write three-line messages with one question, ask for consent on the form, and make every conversation come back into the record.

If you want that channel attached to campaigns that actually produce applications, see how we build candidate acquisition for agencies.