Signal-based outbound stack

Who is this stack for?

Small B2B sales or growth teams (one or two operators) who want to contact accounts when something changes, rather than mailing a static list, and who can run a Clay table themselves.

Which tools are in the stack, and what does each one do?

1. 01Signals

   • RB2B

     Identifies people and companies visiting your website and pushes those visitor profiles into a Clay table as the first trigger.

     Pro from $149/month (Pro is the RB2B plan that can push visitors to Clay)

   • PredictLeads

     Adds hiring, funding, news and tech stack events for target accounts through Clay's PredictLeads actions, so you can filter for accounts with a recent change.

     Free tier (100 API credits/month), then $0.04 per credit with a $40 minimum on your own account

2. 02Orchestration

   • Clay

     Receives signals, scores and filters accounts, finds the right people and runs every enrichment and verification step as table columns.

     Growth from $495/month (monthly) or $446/month (annual); Growth is needed for CRM auto-sync, webhooks and the HTTP API

3. 03Contact data waterfall

   • Prospeo

     First email provider in the Clay waterfall, run on your own Prospeo account; charges 1 credit per verified email and nothing when none is found.

     Starter $49/month (monthly) or $37/month (yearly), 2,000 credits a month

   • Findymail

     Second provider for rows Prospeo could not fill; its plan also includes 5,000 bonus verifier credits.

     Starter $99/month, 5,000 finder credits

4. 04Verification

   • MillionVerifier

     Final check before sending, run from Clay's MillionVerifier action (Growth and above), flagging invalid, risky and catch-all addresses.

     $39 one-off for 10,000 credits that never expire

5. 05Sending

   • Smartlead

     Sends the sequence across unlimited warmed-up mailboxes; Clay's Add Lead to Campaign action drops verified contacts into an existing campaign.

     Pro $94/month (monthly) or $78/month (annual), 30,000 contacts and 90,000 emails a month

6. 06CRM

   • HubSpot

     System of record: Clay creates and updates contacts and companies, and Smartlead's native HubSpot integration logs replies.

     Free tier (up to 2 users); Sales Hub Starter from $20/seat/month on monthly billing in the US

How does data flow through the stack?

1. 1RB2B pushes identified website visitors into a Clay webhook table, and PredictLeads actions add hiring or funding events to target accounts.
2. 2Clay scores each account against your ICP and drops rows without a qualifying signal.
3. 3Clay finds the relevant people at each remaining account and runs Prospeo first, then Findymail, for a work email.
4. 4MillionVerifier checks every found email; invalid rows are removed and catch-all rows are routed to a separate, lower-volume campaign.
5. 5Clay adds verified contacts, with the signal as a personalisation variable, to a Smartlead campaign.
6. 6Clay upserts the contact and company in HubSpot, and Smartlead logs replies against the same record.

How much does this stack cost per month?

About $850 to $1,000 a month, before mailboxes and domains

Assumes one or two users, about 2,000 to 5,000 new contacts a month and HubSpot Free. Low end (annual billing where offered): Clay Growth $446 + RB2B Pro $149 + PredictLeads $0 (free tier) + Prospeo $37 + Findymail $99 + Smartlead $78 + MillionVerifier $39 pack = $848. High end (monthly billing): Clay $495 + RB2B $149 + PredictLeads $40 minimum + Prospeo $49 + Findymail $99 + Smartlead $94 + MillionVerifier $39 = $965, or about $1,005 with two HubSpot Starter seats at $20. Prices are the vendors' published figures checked on 17 October 2026. Sending mailboxes, domains and Clay data credits beyond the plan allowance are extra and not included.

What are the trade-offs?

• Clay Growth is most of the bill. Launch ($167 to $185 a month) also has signals and the Smartlead action, but it has no CRM integrations, webhooks or MillionVerifier action, so you would sync HubSpot from Smartlead instead.
• RB2B's person-level identification covers US visitors only (its Starter plan states 15 to 20% coverage), so a mainly UK or European audience gets less from this layer.
• Running Prospeo and Findymail on your own accounts costs one Clay action per lookup instead of Clay data credits, but adds two more subscriptions to manage.
• Signal volume is uneven: some months produce far fewer qualified accounts than the plan allowances assume, so per-contact cost rises in quiet months.

Questions about this stack

Other GTM stacks

• AI-agent GTM stack with Claude CodeAn AI agent GTM stack: Claude Code with Clay's plugin, n8n, OpenAI, Perplexity and Exa for research, Instantly for sending and HubSpot, with costs.
• Clay-centred enrichment stackA Clay enrichment stack on Growth: Prospeo, LeadMagic and FullEnrich waterfall, ZeroBounce, OpenAI and Perplexity research, and CRM sync, with costs.
• Enterprise outbound stackAn enterprise outbound stack: ZoomInfo, Bombora, Clay, ZeroBounce, Outreach or Salesloft and Salesforce, with published costs and what is contact sales.
• Lean cold email stack for small teamsA lean cold email stack for small teams: Prospeo, MillionVerifier, Smartlead and a free CRM, with verification, warm-up and costs from about $70 a month.
• LinkedIn and email multichannel stackA LinkedIn and email outreach stack: HeyReach with Smartlead, or La Growth Machine, plus Prospeo, Surfe and HubSpot, with published costs per sender.