Campaign Monitor
Compose branded campaigns, manage subscribers, and report delivery and clicks
The core loop is buildable, but a dependable replacement becomes a real weekend or multi-day project. For Campaign Monitor, compose branded campaigns, manage subscribers, and report delivery and clicks. The hard boundary is template editor, deliverability, journeys, agency features, and integrations, plus deliverability, growth network, and integrations.
Build verification: not recorded. How we judge buildability
What you give up
- template editor, deliverability, journeys, agency features, and integrations
- inbox-placement expertise
- advanced automations
- commerce integrations
- recommendation and ad networks
Why people still pay
People still pay for Campaign Monitor because newsletter operators pay for inbox placement, growth mechanics, and operational confidence on publication day. The recurring cost buys DNS authentication, reputation, bounces, complaints, unsubscribe compliance, templates, queues, analytics, backups, and support, not just the visible interface.
Your build guide
The stack, security requirements, and agent rules for a focused replacement.
Before you start
- A verified sending domain, SES account with suitable sending access, DNS ownership and permission-based subscriber records. Provider charges and deliverability work remain.
- Implementation components: Next.js App Router and TypeScript for server-rendered pages and validated mutations. PostgreSQL with Drizzle migrations; Better Auth sessions for a small private workspace. React Email templates, an Amazon SES adapter and a bounded outbox worker with provider event ingestion.
- Scope boundary: template editor, deliverability, journeys, agency features, and integrations; inbox-placement expertise
Use these project rules and optional skill references alongside the prompt. Review each skill before adding it to your agent; the AGENTS.md export includes the same guidance.
Optional external skill: supabase-postgres-best-practices — Review PostgreSQL schemas, queries, indexes, pooling, concurrency and row-level security. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Optional external skill: web-design-guidelines — Review web interfaces for accessibility, keyboard focus, forms, navigation and interaction quality. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Optional external skill: copywriting — Write landing pages and product copy grounded in the intended audience, product value and a clear next action. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Project rule — data model: brand templates, campaign revisions, subscriber segments, merge fields and delivery/suppression events
Project rule — preserve this invariant: Missing merge values use reviewed fallbacks; the sending template and audience cannot change partway through a batch.
Project rule — acceptance evidence: A contact without a first name sees the fallback; pausing and resuming a campaign retains its original revision and skips newly suppressed recipients.
Implementation plan
Phase 1
Scope and fixtures. Implement this bounded workflow: Create reusable branded email layouts, preview merge fields against a sample contact and snapshot a target segment before sending. Retain an editable plain-text counterpart and a public archive only when explicitly chosen. Record prerequisites, select representative user-owned fixtures and document the unsupported features: template editor, deliverability, journeys, agency features, and integrations; inbox-placement expertise
Phase 2
Durable model. Model brand templates, campaign revisions, subscriber segments, merge fields and delivery/suppression events Add migrations or a versioned document format, explicit validation, stable IDs and a visible import-error report. Preserve this rule: Missing merge values use reviewed fallbacks; the sending template and audience cannot change partway through a batch.
Phase 3
Complete the first useful path. Implement the workflow's input, review and output interface, with clear controls and explicit empty/error states. Snapshot the campaign revision and recipient segment. Persist one delivery record per recipient, use provider-supported reconciliation after unknown outcomes, and pause on high failure rates.
Phase 4
Permissions and integration failure. Keep consent evidence and suppression records, validate signed delivery callbacks, and recheck unsubscribes and complaints immediately before every send. Request integration credentials and permissions only for the enabled feature; show a disconnected state instead of mock results.
Phase 5
Portable handoff. Export versioned JSON plus attachments and a readable CSV summary. Restore into a separate database and compare record IDs and attachment checksums before switching. Include setup, operating limits, fixture walkthrough and shutdown/restart instructions in the README.
Phase 6
Acceptance scenarios. A contact without a first name sees the fallback; pausing and resuming a campaign retains its original revision and skips newly suppressed recipients. Repeat the workflow after restart and with a denied permission or unavailable dependency; show recoverable failure rather than a success placeholder.
WORKING SLICE Create reusable branded email layouts, preview merge fields against a sample contact and snapshot a target segment before sending. Retain an editable plain-text counterpart and a public archive only when explicitly chosen. Build this scoped Campaign Monitor-inspired workflow with a documented data model and visible failure states. Architecture - Next.js App Router and TypeScript for server-rendered pages and validated mutations. - PostgreSQL with Drizzle migrations; Better Auth sessions for a small private workspace. - React Email templates, an Amazon SES adapter and a bounded outbox worker with provider event ingestion. Prerequisites and limits A verified sending domain, SES account with suitable sending access, DNS ownership and permission-based subscriber records. Provider charges and deliverability work remain. Outside this release: template editor, deliverability, journeys, agency features, and integrations; inbox-placement expertise Data model and correctness brand templates, campaign revisions, subscriber segments, merge fields and delivery/suppression events Invariant: Missing merge values use reviewed fallbacks; the sending template and audience cannot change partway through a batch. Snapshot the campaign revision and recipient segment. Persist one delivery record per recipient, use provider-supported reconciliation after unknown outcomes, and pause on high failure rates. Security and privacy Keep consent evidence and suppression records, validate signed delivery callbacks, and recheck unsubscribes and complaints immediately before every send. Recovery and export Export versioned JSON plus attachments and a readable CSV summary. Restore into a separate database and compare record IDs and attachment checksums before switching. Implementation order 1. Phase 1 — Scope and fixtures. Implement this bounded workflow: Create reusable branded email layouts, preview merge fields against a sample contact and snapshot a target segment before sending. Retain an editable plain-text counterpart and a public archive only when explicitly chosen. Record prerequisites, select representative user-owned fixtures and document the unsupported features: template editor, deliverability, journeys, agency features, and integrations; inbox-placement expertise 2. Phase 2 — Durable model. Model brand templates, campaign revisions, subscriber segments, merge fields and delivery/suppression events Add migrations or a versioned document format, explicit validation, stable IDs and a visible import-error report. Preserve this rule: Missing merge values use reviewed fallbacks; the sending template and audience cannot change partway through a batch. 3. Phase 3 — Complete the first useful path. Implement the workflow's input, review and output interface, with clear controls and explicit empty/error states. Snapshot the campaign revision and recipient segment. Persist one delivery record per recipient, use provider-supported reconciliation after unknown outcomes, and pause on high failure rates. 4. Phase 4 — Permissions and integration failure. Keep consent evidence and suppression records, validate signed delivery callbacks, and recheck unsubscribes and complaints immediately before every send. Request integration credentials and permissions only for the enabled feature; show a disconnected state instead of mock results. 5. Phase 5 — Portable handoff. Export versioned JSON plus attachments and a readable CSV summary. Restore into a separate database and compare record IDs and attachment checksums before switching. Include setup, operating limits, fixture walkthrough and shutdown/restart instructions in the README. 6. Phase 6 — Acceptance scenarios. A contact without a first name sees the fallback; pausing and resuming a campaign retains its original revision and skips newly suppressed recipients. Repeat the workflow after restart and with a denied permission or unavailable dependency; show recoverable failure rather than a success placeholder. Acceptance A contact without a first name sees the fallback; pausing and resuming a campaign retains its original revision and skips newly suppressed recipients. Use real source data or clearly labeled fixtures. Explain unsupported input and provider failures; do not fabricate analytics, delivery receipts, accuracy claims or security guarantees. Optional agent guidance Optional external skill: [supabase-postgres-best-practices](https://github.com/supabase/agent-skills/blob/main/skills/supabase-postgres-best-practices/SKILL.md) — Review PostgreSQL schemas, queries, indexes, pooling, concurrency and row-level security. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission. Optional external skill: [web-design-guidelines](https://github.com/vercel-labs/agent-skills/blob/main/skills/web-design-guidelines/SKILL.md) — Review web interfaces for accessibility, keyboard focus, forms, navigation and interaction quality. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission. Optional external skill: [copywriting](https://github.com/coreyhaines31/marketingskills/blob/main/skills/copywriting/SKILL.md) — Write landing pages and product copy grounded in the intended audience, product value and a clear next action. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission. Project rule — data model: brand templates, campaign revisions, subscriber segments, merge fields and delivery/suppression events Project rule — preserve this invariant: Missing merge values use reviewed fallbacks; the sending template and audience cannot change partway through a batch. Project rule — acceptance evidence: A contact without a first name sees the fallback; pausing and resuming a campaign retains its original revision and skips newly suppressed recipients.
$ open in your agent (prompt prefilled, you press enter), copy the prompt or copy or download AGENTS.md
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Questions about Campaign Monitor
Can you build your own Campaign Monitor with AI?
Partly. The core loop is buildable, but a dependable replacement becomes a real weekend or multi-day project. For Campaign Monitor, compose branded campaigns, manage subscribers, and report delivery and clicks. The hard boundary is template editor, deliverability, journeys, agency features, and integrations, plus deliverability, growth network, and integrations.
What does the Campaign Monitor build prompt cover?
The prompt starts with this scope: Create reusable branded email layouts, preview merge fields against a sample contact and snapshot a target segment before sending. Retain an editable plain-text counterpart and a public archive only when explicitly chosen. Full-product capabilities excluded from the comparison include: template editor, deliverability, journeys, agency features, and integrations; inbox-placement expertise; advanced automations. Follow the implementation plan and its prerequisites before expanding the build.
How do I use the prompt, AGENTS.md and agent skills?
Start with the Campaign Monitor prerequisites and stack, then copy the prompt into your coding agent. Save the project rules as AGENTS.md in the project root. Linked skills are optional packages or source instructions for specific tasks; review their current contents and install only those matching the chosen stack. A skill does not supply API credentials or verify the finished app.
How long will this Campaign Monitor project take?
The catalogue estimate is multi-day for the limited scope. Setup, integration approvals, debugging, deployment and ongoing maintenance can add time. This is an estimate, not a delivery guarantee.
What would I give up by replacing Campaign Monitor?
template editor, deliverability, journeys, agency features, and integrations; inbox-placement expertise; advanced automations; commerce integrations; recommendation and ad networks. People still pay for Campaign Monitor because newsletter operators pay for inbox placement, growth mechanics, and operational confidence on publication day. The recurring cost buys DNS authentication, reputation, bounces, complaints, unsubscribe compliance, templates, queues, analytics, backups, and support, not just the visible interface.
What price is this guide comparing against?
The recorded Lite plan is $12/mo (monthly), checked 2026-07-31. Check the linked pricing source before buying. Building your own also has hosting, API and maintenance costs; the recorded amount is not a guaranteed saving.
What can I use instead of building Campaign Monitor?
listmonk: Campaigns, segments and analytics in one fast compose file; templates favor competence over theatre. Keila: A friendly campaign editor, forms and tracking without contact pricing; delivery is your SMTP provider's job. Notifuse: Visual MJML campaigns, scheduling, A/B tests and analytics; bring PostgreSQL and a sender. Compare all listed options at https://howtovibecodeit.dev/campaign-monitor/alternatives. Check each option's license, hosting needs and feature limits.