MVP spec

The MVP is one product shipped in two releases. Release A (desk) sits on top of the sequencers agencies already pay for. Release B (sender) replaces the sequencer underneath, reusing every desk module. The rule for both: build what an agency resells to its clients (approvals, reports, meeting proof, isolation) and what the leaders structurally will not (country rules, never-compete, honest billing). Buy or integrate the rest. See The wedge for why, and Build costs and team for the 3–4 engineer, 4–6 month envelope this has to fit.

#Must: Release A, the desk (target: partners live by 11 Dec 2026)

#Must: Release B, the sender (target: first partner client migrated by Apr 2027)

#Should (months 6–12)

• Inbox purchase through a partner API (InboxKit or Zapmail), domains registered in the customer's legal name, published cost-plus (Transparent infrastructure, Infrastructure strategy: build or partner).
• Rebilling: pass inboxes and usage to each client with the agency's markup (Agency operating system).
• CRM push to HubSpot and Pipedrive per client; Salesforce later (CRM sync).
• LinkedIn replies merged into the thread via HeyReach's API, not our own automation (HeyReach, Multichannel: LinkedIn, calls, SMS and video).
• Slack approvals and a mobile approval view.
• MCP server with the same scopes and caps (API, webhooks and MCP).
• Placement from live sends, with optional seed tests through EmailGuard or MailReach (Inbox placement testing).
• DACH destinations: seeds and routing for GMX/WEB.DE, T-Online and IONOS, if the MX scan shows they matter (ESP matching).
• Microsoft SMTP AUTH checker as a free tool (Microsoft-first outbound).
• Legal-form flag for UK sole traders from Companies House data (UK: PECR and DUAA 2025).

#Later (year two and beyond)

Google OAuth with restricted scopes after CASA (OAuth verification and the end of basic auth). SSO/SCIM, audit export, SOC 2 and two-way Salesforce sync for Governed volume for sales teams. A signal-triggered campaign mode (Signal-triggered sequencer). EU-hosted isolated IP pools on KumoMTA, priced like EmailBison (Infrastructure strategy: build or partner). EU-provenance data sources such as Dropcontact (Data at cost). A productised sending API (Sending engine as an API).

#Never

#Data model sketch

agency            id, legal_entity, aup_status, plan, eu_region
client_workspace  id, agency_id, brand, default_countries, pool_id, approvers[]
user_role         user_id, scope(agency|workspace|campaign|mailbox), role(owner|operator|client_viewer|client_approver)
domain            id, workspace_id, owner_legal_name, supplier, spf/dkim/dmarc, suspensions[]
mailbox           id, domain_id, provider, auth_type, health_state, cap_today, pool_id
campaign/step/variant
contact           id, email, country, address_type(generic|named), legal_form, role
provenance        contact_id, source, collected_at, basis, notice_sent_at
rule_set          version, country, address_type, verdict(allow|warn|block), source_url, confidence
send_decision     message_id, rule_set_version, verdict, override_by
thread            id, lead_identity, channels(email|linkedin), external_ref(sequencer, id)
reply             id, thread_id, class, confidence, received_at
draft             id, reply_id, author(human|ai), approved_by, approved_at, sent_message_id
meeting           id, thread_id, booked_at, held_at, disputed, billable
objection         email_hash, scope(workspace|agency|global), reason, abmahnung_flag
audit_event       actor(user|api_key|agent), action, object, at

Two design rules. external_ref lets the same thread live in a Smartlead campaign today and in your own engine tomorrow, which is what makes Release A reusable. Scopes and audit_event.actor exist from day one because retrofitting tenancy is exactly Instantly's white-label problem and Governed volume for sales teams will need them.

#Parity checklist for agencies (as of Oct 2026)

Sources: Instantly, Smartlead, EmailBison, API, webhooks and MCP, Mailbox health engine.

#What this means for an entrant

• Ship Release A in eight weeks with three connectors and the opt-out path working perfectly. A missed opt-out is a legal event, not a bug (The first 90 days).
• Accept the deliberate gaps (no warmup pool, no database, no dedicated IPs in year one) and say so on the pricing page (Pricing strategy).
• Make rule_set public. A versioned, sourced country table is content marketing competitors would have to rebuild (Go-to-market plan).
• Treat the mailbox, not the campaign, as the unit of protection. That is the retention engine (Mailbox health engine).
• Keep external_ref and scopes in the schema from the first commit. They are what let one codebase serve the overlay, the sender and year-two SDR teams.