Build AI B2B Marketing Tech Stack

I am looking for an experienced automation developer to build an end-to-end B2B sales and lead generation workflow. The goal is to create a system that can identify qualified prospects, enrich their contact information, organize them in a CRM, conduct personalized outbound outreach, manage follow-ups, and move qualified prospects through the sales pipeline with minimal manual work. Core Workflow The system should be designed to automate the following process: Lead Discovery → Lead Enrichment → Lead Qualification → CRM → Personalized Outreach → Automated Follow-ups → Meeting Scheduling → Proposal/Quote → Contract → Customer Onboarding 1. Lead Generation Build a system that can identify potential B2B customers based on defined criteria such as: Industry Company size Geographic location Number of locations Website characteristics Relevant job titles/decision makers Other customizable qualification criteria The system should be capable of generating large prospect lists while minimizing duplicate or low-quality leads. 2. Lead Enrichment Automatically enrich prospects with available information, including: Company name Website Industry Location Company size Decision maker/contact name Job title Business email Phone number where available LinkedIn profile where available Other relevant firmographic information 3. Lead Scoring & Qualification Create customizable rules for automatically scoring prospects based on predefined criteria. The system should categorize leads into tiers such as: High priority Medium priority Low priority Disqualified The scoring criteria should be easy for me to modify without needing to rebuild the entire system. 4. CRM Integration Set up and configure a CRM, preferably HubSpot, including: Contact management Company records Deal pipeline Lead stages Custom fields Tasks Follow-up reminders Activity tracking Email tracking Reporting/dashboard All relevant information generated throughout the workflow should automatically synchronize with the CRM. 5. Personalized Email Outreach Build automated outbound email campaigns that can personalize messages based on information associated with each prospect. The system should support: Personalized first-touch emails Multiple follow-up sequences Different campaigns based on lead characteristics Automatic campaign enrollment Automatic removal when a prospect responds Bounce handling Unsubscribe handling Reply detection Campaign performance tracking Email deliverability and proper domain/email setup are important requirements. 6. Automated Follow-Up Create customizable follow-up sequences based on prospect behavior. For example: Day 1: Initial outreach Day 4: Follow-up Day 8: Follow-up Day 14: Final follow-up The system should automatically stop or modify the sequence when the prospect responds, books a meeting, becomes disqualified, or otherwise changes status. 7. Meeting Scheduling Integrate a scheduling platform such as Calendly so qualified prospects can easily schedule meetings. When a meeting is booked: Update the CRM Update the lead/deal stage Record the meeting information Create appropriate follow-up tasks Remove the prospect from irrelevant outreach sequences 8. Proposal & Quote Workflow Create a workflow for generating and sending professional proposals/quotes after a qualified sales opportunity. Ideally, the system should be capable of pulling relevant information from the CRM into a standardized proposal or quote template. Potential tools include PandaDoc or similar platforms. 9. Contract & Closing Workflow After a prospect accepts a proposal: Generate/send the appropriate agreement Collect an electronic signature Update the CRM Move the opportunity to the appropriate stage Trigger customer onboarding workflows 10. Automation/Integration Layer Use an automation platform such as: n8n Zapier Make APIs/webhooks Other appropriate automation technologies I am open to your recommendation regarding the best architecture. The system should be modular, reliable, and easy to maintain. Preferred Technology Experience Strong experience with several of the following is preferred: HubSpot Clay Apollo LinkedIn Sales Navigator n8n Zapier Make OpenAI/API integrations Email automation platforms PandaDoc DocuSign Calendly REST APIs Webhooks CRM integrations Email deliverability B2B sales automation You do not need to use every platform listed above. I am looking for someone who can recommend the most efficient and cost-effective architecture. Important Requirements The system must: Be built in accounts that I own and control Be fully documented Have clearly organized workflows Include error handling Avoid duplicate records Maintain accurate CRM data Be scalable as lead volume increases Allow me to modify lead criteria and campaigns Include appropriate testing before launch Include documentation explaining how everything works I do not want a collection of disconnected automations. I want a cohesive end-to-end sales system. Deliverables The successful developer will be responsible for: Designing the overall system architecture Setting up/configuring the required platforms Building the integrations and workflows Configuring the CRM Building lead-generation and enrichment workflows Building lead scoring Building outbound email sequences Building automated follow-ups Connecting scheduling Building proposal/quote workflows Connecting electronic signatures Building CRM automations Testing the entire workflow Providing documentation Providing a handover/training session Budget & Project Structure I prefer to work on a milestone basis rather than paying the entire project fee upfront. Please provide: Your proposed total project price Estimated timeline Recommended technology stack Examples of similar systems you have built A brief explanation of your proposed architecture What is included in your price Any recurring software/API costs I should expect Preference will be given to developers who have previously built end-to-end B2B sales automation systems, rather than developers whose experience is limited to simple Zapier integrations. Please include examples of previous relevant projects in your proposal.