SaneBox
Server-side email filtering, reminders, and inbox cleanup
The visible email triage loop is buildable, but a credible replacement needs more than the first screen. SaneBox earns its keep through deliverability, security, integration, so expect a weekend or multi-day build and a narrower personal scope.
Build verification: not recorded. How we judge buildability
What you give up
- push reliability across devices
- team routing and shared inbox rules
- abuse response and security operations
- sender reputation, deliverability, and suppression handling
- provider-grade deliverability
Why people still pay
SaneBox: Email is infrastructure. Customers pay to avoid lost messages, broken auth, spam problems, and the reputational cost of a flaky inbox.
Your build guide
The stack, security requirements, and agent rules for a focused replacement.
Before you start
- Runtime and tools: TypeScript, React and a Node server with SQLite for a single small workspace.
- Before starting: A local Node runtime, writable data directory, sample records and a documented backup/restore path.
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.
Project rule — domain: Store MailboxGeneration, MessageUID, SenderRule, ProposedMove and MoveReceipt; user corrections take precedence over future model classification and message content remains unchanged.
Project rule — scope and recovery: Start with exported mail or one authorized IMAP account. Do not delete mail automatically, claim perfect spam detection or hide server errors behind a local folder view.
Project rule — acceptance: Misclassify a known sender, undo the move and refresh; the message returns and the corrected rule prevents repeated misfiling.
Project rule — delivery: document real setup commands and permissions; do not claim a build, accuracy level, performance result or security certification that has not been demonstrated.
Recommended skill: vercel-react-best-practices — keep the proposed React work/review views responsive and avoid unnecessary rendering or data-fetch waterfalls. Follow the maintainer's installation instructions and match its requirements to the chosen runtime.
Recommended skill: web-design-guidelines — review keyboard access, focus, validation, error recovery and the readable work/review interface or HTML report. Follow the maintainer's installation instructions and match its requirements to the chosen runtime.
Implementation plan
Phase 1
Pin the working slice and create its example input: Build a single-mailbox triage assistant that proposes folder moves using explicit sender/rule preferences and shows a reversible review queue. Confirm setup: A local Node runtime, writable data directory, sample records and a documented backup/restore path.
Phase 2
Implement persistence and write-time invariants before decorating the UI: Store MailboxGeneration, MessageUID, SenderRule, ProposedMove and MoveReceipt; user corrections take precedence over future model classification and message content remains unchanged.
Phase 3
Connect the working view to real saved state. Use migrations and server-side validation; expose saved, pending and failed states. Keep each write atomic and reject stale edits using a revision number.
Phase 4
Expose the app-specific limits and recovery path in context: Start with exported mail or one authorized IMAP account. Do not delete mail automatically, claim perfect spam detection or hide server errors behind a local folder view.
Phase 5
Walk through this concrete acceptance case and preserve its exported evidence: Misclassify a known sender, undo the move and refresh; the message returns and the corrected rule prevents repeated misfiling. Finish the README and backup/restore instructions; report unfinished capabilities explicitly.
Build the following focused alternative to SaneBox. This is a deliberately limited personal or small-team substitute, not parity with the paid service. WORKING SLICE Build a single-mailbox triage assistant that proposes folder moves using explicit sender/rule preferences and shows a reversible review queue. SETUP AND ARCHITECTURE Use TypeScript, React and a Node server with SQLite for a single small workspace. Prerequisites: A local Node runtime, writable data directory, sample records and a documented backup/restore path. Before integrating anything, record actual versions and permissions, plus model files or provider limits only where used, in the README; make unavailable dependencies visible rather than simulating success. DOMAIN MODEL AND INVARIANTS Store MailboxGeneration, MessageUID, SenderRule, ProposedMove and MoveReceipt; user corrections take precedence over future model classification and message content remains unchanged. IMPLEMENTATION CONTRACT Use migrations and server-side validation; expose saved, pending and failed states. Keep each write atomic and reject stale edits using a revision number. Provide an input/setup view, the main work view, and a review/export view appropriate to this workflow. Preserve the last saved state if a job or save fails. Include empty, loading, permission-denied, partial and retryable-error states. Log identifiers and error categories without secret values or unnecessary private content. APP-SPECIFIC BOUNDARY AND RECOVERY Start with exported mail or one authorized IMAP account. Do not delete mail automatically, claim perfect spam detection or hide server errors behind a local folder view. ACCEPTANCE SCENARIO Misclassify a known sender, undo the move and refresh; the message returns and the corrected rule prevents repeated misfiling. Also reopen the app after an interrupted operation, confirm the saved record/export remains inspectable, and document the recovery action. These are implementation acceptance requirements, not a claim that this guide has been tested. DELIVERY Deliver a runnable repository with migrations or project-format versioning, a non-sensitive example, environment/permission setup, the exact manual acceptance steps, and a backup/export-and-restore walkthrough. Implement the working slice before optional integrations; list any deferred paid-product capabilities honestly. Do not add capabilities outside the working slice just to resemble the original product. PROJECT RULES FOR AGENTS.md Keep the domain invariants above executable at the write boundary. Propose scope changes before adding providers or permissions. Never fabricate source evidence, publish results, identity matches or successful delivery. Preserve user originals and require an explicit confirmation for destructive changes or external publication.
$ open in your agent (prompt prefilled, you press enter), copy the prompt or copy or download AGENTS.md · generated from this app's build plan
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SaneBox pricing
| plan | monthly | annual (per mo) | what you get |
|---|---|---|---|
| snack | $7 | $4.92 | 1 email account; choose any 2 SaneBox features and swap those selections at any time.$59/year; lowest rate is $109 for 2 years ($4.54/month effective). |
| lunch | $12 | $8.25 | Up to 2 email accounts; choose any 6 SaneBox features and swap those selections at any time.$99/year; lowest rate is $179 for 2 years ($7.46/month effective). |
| dinner | $36 | $24.92 | Up to 4 email accounts; access to all SaneBox features.$299/year; lowest rate is $529 for 2 years ($22.04/month effective). |
free tierno free tier; 7-day full-feature trial
billingmonthly + annual + 2-year prepaid; plans auto-renew
hidden costsLower tiers cap both connected mailboxes and selectable features; more than 4 email accounts requires contacting support. The lowest advertised rates require a 24-month prepayment ($109/$179/$529).
pricing sources checked 2026-08-12 · pricing source ↗
Questions about SaneBox
Can you build your own SaneBox with AI?
Partly. The visible email triage loop is buildable, but a credible replacement needs more than the first screen. SaneBox earns its keep through deliverability, security, integration, so expect a weekend or multi-day build and a narrower personal scope.
What does the SaneBox build prompt cover?
The prompt starts with this scope: Build a single-mailbox triage assistant that proposes folder moves using explicit sender/rule preferences and shows a reversible review queue. Full-product capabilities excluded from the comparison include: push reliability across devices; team routing and shared inbox rules; abuse response and security operations. 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 SaneBox 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 SaneBox project take?
The catalogue estimate is weekend to 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 SaneBox?
push reliability across devices; team routing and shared inbox rules; abuse response and security operations; sender reputation, deliverability, and suppression handling; provider-grade deliverability. SaneBox: Email is infrastructure. Customers pay to avoid lost messages, broken auth, spam problems, and the reputational cost of a flaky inbox.
What can I use instead of building SaneBox?
Inbox Zero: Server-side AI rules, follow-up tracking and bulk cleanup for Gmail or Outlook; self-hosting starts with OAuth, Docker and a model. Check each option's license, hosting needs and feature limits.