InboxThread — The Follow-Up CRM for Solopreneurs Who Lose Deals in Three Different DM Tabs

Q: Who can build InboxThread — The Follow-Up CRM for Solopreneurs Who Lose Deals in Three Different DM Tabs?

This is a intermediate level project. Solopreneurs and 1-5 person service agencies managing 10-50 active leads across multiple channels — estimated 2M+ in the US alone.

Q: How does InboxThread — The Follow-Up CRM for Solopreneurs Who Lose Deals in Three Different DM Tabs make money?

SaaS subscription. Free tier: 3 contacts. Paid $49/month: unlimited contacts, follow-up scheduling, reminders.

Your next client texted you, DMed you on Instagram, and emailed you — and you forgot to reply to all three. InboxThread pulls Gmail, SMS via Twilio, and Instagram DMs into one chronological view per contact, with one-click follow-up scheduling. Stop losing $2k deals because you forgot which app they messaged you on.

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Difficulty

intermediate

What is it?

Solopreneurs and tiny agencies manage leads across Gmail, Instagram DMs, and SMS simultaneously, and every tool either costs $200/month or ignores two of the three channels. InboxThread creates a per-contact thread view that aggregates all touchpoints, shows the last message date, and lets you schedule a follow-up in two clicks. The MVP is a web app with OAuth for Gmail, Instagram Graph API for DMs, and Twilio for SMS — all three are stable, documented, and free-tier accessible. Precedent exists in tools like Front and Missive, but neither targets the $49/month solopreneur who has five active leads and no CRM budget. This ships in two weeks because the hard part is auth, not AI.

Why now?

Instagram Graph API for DMs became stable and accessible to small apps in late 2024, and the June 2026 vibe-coding wave means solopreneurs expect a tool like this to exist — the API access barrier that blocked this two years ago is gone.

▸Unified per-contact thread view aggregating Gmail, SMS, and Instagram DMs in chronological order
▸One-click follow-up scheduler with reminder push notification via Resend email
▸Lead status tags (hot, warm, cold) applied per contact with last-contacted timestamp
▸Quick reply composer that sends from the correct channel the contact last used

Target Audience

Solopreneurs and 1-5 person service agencies managing 10-50 active leads across multiple channels — estimated 2M+ in the US alone.

Example Use Case

Maria runs a freelance brand design studio, connects her Gmail and Instagram in 90 seconds, sees all 12 open lead threads in one view, schedules three follow-ups, and closes a $3,500 project she had forgotten about for five days.

User Stories

▸As a freelance designer, I want to see all messages from a lead in one thread regardless of channel, so that I never lose context before a follow-up call.
▸As a solopreneur, I want to schedule a follow-up reminder for a contact, so that I stop relying on memory and close more deals.
▸As a 5-person agency owner, I want to see which leads have gone cold by last-contacted date, so that I can prioritize outreach each Monday morning.

Done When

✓Unified inbox: done when messages from Gmail, SMS, and Instagram DMs for the same contact appear in a single chronological thread without any manual merging.
✓Follow-up scheduler: done when user clicks a date on a contact thread and receives a reminder email at that exact time.
✓Channel-aware reply: done when user sends a reply from the inbox and the message is delivered via the same channel the contact last used.
✓Lead status: done when user can tag a contact as hot/warm/cold and filter the inbox by that tag in under 3 clicks.

Is it worth building?

$49/month x 50 users = $2,450 MRR at month 3. $49/month x 200 users = $9,800 MRR at month 8. Math assumes 3% conversion from ProductHunt traffic and Slack community outreach.

Unit Economics

CAC: $8 via Slack community posts (free). LTV: $588 (12 months at $49/month). Payback: immediate. Gross margin: 91%.

Business Model

SaaS subscription

Monetization Path

Free tier: 3 contacts. Paid $49/month: unlimited contacts, follow-up scheduling, reminders.

Revenue Timeline

First dollar: week 3 via first paid beta upgrade. $1k MRR: month 3. $5k MRR: month 7. $10k MRR: month 12.

Estimated Monthly Cost

Supabase: $25, Vercel: $20, Twilio SMS: $15 at launch volume, Resend: $10, Stripe fees: ~$25. Total: ~$95/month.

Profit Potential

Full-time viable at $8k-$15k MRR with zero paid acquisition if launched into Slack freelancer communities.

Scalability

High — add WhatsApp via Twilio, LinkedIn DMs, team inbox splitting, and CRM export integrations.

Success Metrics

Week 1: 200 signups from Slack communities. Week 3: 20 paid conversions. Month 3: 80% monthly retention.

Launch & Validation Plan

Post in r/freelance and three freelancer Slack communities asking how they track follow-ups — 50 responses in 48 hours validates the pain before a line of code.

Customer Acquisition Strategy

First customer: DM 30 freelancers in the Designer Hangout Slack offering three months free in exchange for two feedback calls. Ongoing: ProductHunt launch, r/freelance, r/Entrepreneur, and Twitter/X threads showing the before/after of a missed follow-up recovered.

What's the competition?

Competition Level

Medium

What's the roadmap?

Feature Roadmap

V1 (launch): unified inbox, follow-up scheduler, lead status tags, channel-aware reply. V2 (month 2-3): WhatsApp via Twilio, CSV contact import, weekly digest email. V3 (month 4+): AI reply suggestions, team inbox, CRM export to HubSpot.

Milestone Plan

Phase 1 (Week 1-2): schema, OAuth flows for all three channels, inbox UI ships. Phase 2 (Week 3-4): follow-up scheduler, reply composer, Stripe billing live. Phase 3 (Month 2): 20 paying users, retention feedback loop, V2 scoping.

How do you build it?

Tech Stack

Next.js, Supabase, Twilio SMS API, Gmail API, Instagram Graph API, Resend for reminders, Stripe — build with Cursor for API routes, v0 for inbox UI components

Suggested Frameworks

Next.js App Router, Supabase Auth, Twilio Node SDK

Time to Ship

2 weeks

Required Skills

OAuth integrations for Gmail and Instagram, Twilio webhooks, Supabase RLS, Next.js API routes.

Resources

Gmail API docs, Instagram Graph API docs, Twilio Conversations docs, Supabase auth guide.

MVP Scope

app/page.tsx (landing + hero), app/dashboard/page.tsx (unified inbox view), app/api/gmail/route.ts (Gmail OAuth + fetch), app/api/instagram/route.ts (IG Graph API fetch), app/api/sms/route.ts (Twilio webhook receiver), app/api/followup/route.ts (schedule reminder), lib/db/schema.ts (contacts, messages, followups tables), components/ContactThread.tsx (per-contact thread UI), components/ReplyComposer.tsx (channel-aware reply box), seed.ts (demo contact with fake threads), .env.example (all API keys listed)

Core User Journey

Architecture Pattern

Gmail/IG/Twilio webhook -> Supabase inbound queue -> contact matcher -> thread aggregator in Postgres -> Next.js inbox UI -> follow-up scheduler -> Resend reminder email.

Data Model

User has many Contacts. Contact has many Messages (source: gmail/instagram/sms). Contact has many FollowUps. FollowUp has one ReminderEmail.

Integration Points

Gmail API for email threads, Instagram Graph API for DMs, Twilio for SMS, Supabase for database and auth, Resend for reminder emails, Stripe for billing.

V1 Scope Boundaries

V1 excludes: team shared inboxes, WhatsApp, LinkedIn DMs, mobile app, AI reply suggestions, CRM export.

Success Definition

A paying stranger connects all three channels, schedules a follow-up, and renews after month one without any founder intervention.

Challenges

Instagram Graph API requires a business account and app review — this is the hardest non-technical blocker and will take 3-5 days to get approved; plan for it before launch.

Avoid These Pitfalls

Instagram Graph API app review can block launch for a week — submit the review on day one, not after building. Do not build team features before validating single-user retention past 30 days. Do not store full DM message bodies without explicit user consent checkbox.

Security Requirements

Supabase Auth with Google OAuth. RLS on all user tables. API tokens encrypted at rest in Supabase vault. Rate limiting 60 req/min per user via Next.js middleware. GDPR: one-click data deletion endpoint.

Infrastructure Plan

Vercel for Next.js hosting, Supabase for Postgres and auth, Resend for transactional email, Twilio for SMS, GitHub Actions for CI. Sentry for error tracking.

Performance Targets

100 DAU at launch, 2,000 req/day. Inbox load under 500ms. Page LCP under 2s. No caching needed at launch scale.

Go-Live Checklist

☐Security audit complete.
☐Payment flow tested end-to-end.
☐Sentry error tracking live.
☐Vercel monitoring dashboard active.
☐Custom domain with SSL live.
☐Privacy policy and terms published.
☐5 beta users completed full workflow.
☐Rollback plan: revert to previous Vercel deployment.
☐ProductHunt and Slack launch posts drafted.

First Run Experience

On first run: app shows a demo contact called 'Alex Chen' with three pre-seeded messages across Gmail, SMS, and Instagram. User can immediately browse the thread, click Schedule Follow-Up, and see how the reminder flow works. No manual config required: demo data loads without any API keys connected.

How to build it, step by step

1. Define Supabase schema for contacts, messages, followups tables with RLS policies before touching UI. 2. Run npx create-next-app with TypeScript and Tailwind. 3. Install Supabase client, Twilio SDK, and Resend SDK. 4. Build Gmail OAuth route using Google APIs Node client and store tokens in Supabase. 5. Build Instagram Graph API OAuth route and message fetch endpoint. 6. Build Twilio inbound SMS webhook endpoint that maps to contacts by phone number. 7. Build ContactThread component that renders messages sorted by timestamp across all sources. 8. Build ReplyComposer that detects last channel used and sends via correct API. 9. Build follow-up scheduler with a Supabase cron job that triggers Resend reminder emails. 10. Deploy to Vercel, verify the full flow: connect Gmail, receive a test DM, schedule follow-up, receive reminder email.

Generated

June 7, 2026

Model

claude-sonnet-4-6

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Disclaimer: Ideas on this site are AI-generated and may contain inaccuracies. Revenue estimates, market demand figures, and financial projections are illustrative assumptions only — not financial advice. Do your own research before making any business or investment decisions. Technology availability, pricing, and market conditions change rapidly; always verify details independently.