AI Engineer for a Recruitment Automation / HubSpot

We are a recruitment company looking for an AI developer to build a candidate engagement and screening platform around our existing HubSpot CRM. We have a large number of candidates sitting in HubSpot who haven't been contacted for some time. We want to automatically reconnect with these candidates, find out who is still interested and carry out an initial screening before passing relevant candidates back to our recruitment team. The process would start by pulling inactive candidates from HubSpot and contacting them by email and WhatsApp. If a candidate responds and is interested, the system should call them and use an AI voice agent to carry out an initial conversation/interview. The call should use the information we already have about the candidate in HubSpot and ask relevant questions around their experience, current situation, availability and interest. The conversation should adapt based on the candidate's answers rather than just going through the same set of questions every time. After the call, we want a summary and any useful information collected during the conversation to be saved back into HubSpot. Our recruiters should then be able to see which candidates are worth following up with. We will also need a simple platform/dashboard for our team to see candidate activity, messages, calls, interview summaries and follow-ups. We already have HubSpot and the candidate data. We have looked at tools such as **n8n** for some of the automation, but we are open to how this should actually be built. We don't have a fixed technology stack and would rather have someone with experience recommend the right setup. When applying, please explain how you would build this, including: * What technologies/services you would use for the application itself and where you would host it. * Whether you would use n8n or build the workflows directly in the application, and why. * What you would use for WhatsApp, email and AI voice calls. * What you would use for storing call transcripts, summaries and other data. * What you expect the ongoing platform costs to look like. * How long you think it would take to get an initial working version live. Previous experience is important to us. We are particularly interested in developers who have already built AI voice agents, CRM automation, recruitment systems or similar lead/candidate engagement platforms. Please share something similar you have built before, ideally something we can see or test, and explain which parts you personally worked on. We are looking to start immediately, so please also mention your current availability.