TaskDrop - Mobile-First Kanban That Lives Inside Slack

Trello's mobile app is basically a punishment. TaskDrop is a Slack-native kanban board where your team can create, assign, drag, and complete tasks from their phones without ever touching a desktop. Built for the 8 million Slack teams who gave up on Trello mobile and started texting tasks instead.

𝕏 Post Reddit HN

Difficulty

intermediate

What is it?

The pain is real: Slack teams use Trello on desktop but the moment someone tries to assign or move a card on mobile, the experience collapses. TaskDrop solves this by living entirely inside Slack as a bot plus a lightweight Progressive Web App that launches from a Slack shortcut. Cards are created with a slash command, assigned with @mention, and the PWA gives a swipeable drag-drop board that works flawlessly on iOS and Android. No new app to download, no new login — if you're in Slack, you're in TaskDrop. Revenue math: $25/month per team times 100 teams equals $2,500 MRR by month 3, realistic via cold DMs to Slack community admins. This ships fast because the Slack Bolt SDK handles all the bot scaffolding, and the PWA board is a single-page React app with Supabase real-time sync.

Why now?

Slack's Block Kit and Bolt SDK matured enough in 2025 to support rich modals and real-time webhooks without enterprise approval, making Slack-native productivity apps finally fast to ship.

▸Slack slash command to create and assign cards without leaving the chat (Implementation note: Slack Bolt handles the shortcut modal)
▸Mobile-optimized PWA kanban with swipe-to-move column gestures that works on iOS Safari
▸Real-time board sync so every card move appears instantly in Slack as a thread update
▸Per-team billing via Stripe with Slack workspace as the billing unit

Target Audience

Small Slack teams of 3-15 people who manage tasks inside Slack and hate context-switching to Trello or Asana, especially on mobile.

Example Use Case

A 6-person remote agency uses TaskDrop so their PM can assign tasks from her iPhone during client calls without switching apps, and the team sees updates instantly in their Slack channel.

User Stories

▸As a project manager, I want to create and assign tasks from my iPhone inside Slack, so that I never have to open a laptop to update the board.
▸As a team member, I want to see card moves reflected instantly in our Slack channel, so that I know when my task status changes without checking a separate app.
▸As a team admin, I want to pay a flat monthly fee per workspace, so that I can budget predictably without per-seat complexity.

Done When

✓Task creation: done when user types /task in Slack on mobile, fills the modal, and the card appears on the PWA board within 2 seconds.
✓Mobile drag-drop: done when user drags a card to a different column on an iPhone Safari browser without the card snapping back or freezing.
✓Slack sync: done when moving a card on the PWA automatically posts a short status update message in the team's designated Slack channel.
✓Payment: done when team admin clicks upgrade, completes Stripe checkout, and the board immediately unlocks unlimited cards without a page refresh.

Is it worth building?

$25/month per team times 100 teams equals $2,500 MRR. $25/month times 400 teams equals $10,000 MRR by month 8.

Unit Economics

CAC: $15 via Reddit and cold DM outreach. LTV: $300 (12 months at $25/month). Payback: 1 month. Gross margin: 85%.

Business Model

SaaS subscription per team

Monetization Path

Free tier for 1 board, 3 members. Paid at $25/month unlocks unlimited boards, assignments, and mobile drag-drop.

Revenue Timeline

First dollar: week 3 via beta upgrade. $1k MRR: month 2. $5k MRR: month 7.

Estimated Monthly Cost

Supabase: $25, Vercel: $20, Slack API: free, Stripe fees: ~$20. Total: ~$65/month at launch.

Profit Potential

Full-time viable at $5k–$10k MRR with a lean solo operation.

Scalability

High — add per-seat pricing, Notion/Linear sync, and team analytics as growth features.

Success Metrics

Week 2: 15 beta teams installed. Month 1: 10 paying teams. Month 3: 60-day retention above 70%.

Launch & Validation Plan

Post in 5 Slack-focused subreddits asking if mobile task management is painful, DM 20 Slack community admins offering free setup.

Customer Acquisition Strategy

First customer: post in r/slack and r/projectmanagement describing the mobile Trello pain, offer 3 months free to the first 10 teams who reply. Then: Slack App Directory listing, ProductHunt, cold DMs to Slack community admins on Twitter/X.

What's the competition?

Competition Level

Medium

What's the roadmap?

Feature Roadmap

V1 (launch): board creation, task assignment, mobile PWA, Slack sync. V2 (month 2-3): due dates, card comments, Slack DM reminders. V3 (month 4+): Notion/Linear import, per-seat pricing, analytics.

Milestone Plan

Phase 1 (Week 1-2): Supabase schema, Slack bot, basic CRUD API ships. Phase 2 (Week 3): PWA kanban board with drag-drop and Realtime sync ships. Phase 3 (Month 2): Stripe billing live, 10 paying teams onboarded.

How do you build it?

Tech Stack

Next.js PWA, Slack Bolt SDK, Supabase Realtime, Stripe — build with Cursor for backend and bot logic, v0 for the kanban board UI.

Suggested Frameworks

Slack Bolt SDK, Supabase Realtime, React Beautiful DND

Time to Ship

3 weeks

Required Skills

Slack Bolt SDK, React PWA, Supabase Realtime, Stripe billing.

Resources

Slack API docs, Supabase Realtime quickstart, React Beautiful DND docs, Stripe docs.

MVP Scope

app/page.tsx (PWA board UI), app/api/slack/route.ts (Slack event handler), app/api/tasks/route.ts (CRUD endpoints), lib/db/schema.ts (Drizzle schema for tasks and boards), components/KanbanBoard.tsx (drag-drop board), components/TaskCard.tsx (card UI), lib/slack.ts (Bolt client setup), seed.ts (demo board data), .env.example (SLACK_BOT_TOKEN, SUPABASE_URL, STRIPE_KEY).

Core User Journey

Install Slack app -> create first board via slash command -> open PWA on mobile -> drag card to done -> team sees Slack update.

Architecture Pattern

Slack slash command -> Bolt webhook handler -> Supabase write -> Realtime broadcast -> PWA board updates -> Slack message posted on card change.

Data Model

Workspace has many Boards. Board has many Columns. Column has many Tasks. Task has one Assignee (Slack user ID) and belongs to one Board.

Integration Points

Slack Bolt SDK for bot and events, Supabase for database and realtime, Stripe for payments, Vercel for hosting.

V1 Scope Boundaries

V1 excludes: mobile native app, Trello import, time tracking, guest access, and white-label.

Success Definition

A team admin installs TaskDrop from a link, creates their first board, assigns a task to a teammate on mobile, and pays without any founder involvement.

Challenges

Slack's app distribution requires Marketplace approval for public listing — plan to distribute via direct install link first and avoid the review queue until validated.

Avoid These Pitfalls

Do not wait for Slack Marketplace approval before finding first 10 customers — use a direct install URL. Do not build team analytics before validating the core board workflow. Do not charge per seat before proving per-team pricing holds.

Security Requirements

Supabase Auth with Slack OAuth. RLS on all board and task tables scoped to workspace_id. Rate limiting 60 req/min per Slack workspace via middleware. Input sanitization on all task text fields.

Infrastructure Plan

Vercel for Next.js frontend and API routes, Supabase for Postgres and Realtime, GitHub Actions for CI, Sentry for error tracking — estimated $65/month.

Performance Targets

100 DAU at launch, 2,000 req/day. Supabase Realtime board sync under 300ms. PWA initial load under 2s on 4G mobile.

Go-Live Checklist

☐Security audit complete.
☐Payment flow tested end-to-end.
☐Sentry error tracking live.
☐Supabase RLS policies verified.
☐Custom domain with SSL live.
☐Privacy policy and terms published.
☐5 beta teams signed off.
☐Rollback plan documented.
☐ProductHunt and Reddit launch post drafted.

First Run Experience

On first run: a demo workspace with one board called 'Sprint Board' is pre-seeded with 3 columns and 6 sample tasks. User can immediately drag cards, click to assign, and see the board update in real time. No manual config required: demo board loads without Slack connection for the first 5 minutes.

How to build it, step by step

1. Define Supabase schema for workspaces, boards, columns, tasks in schema.ts. 2. Run npx create-next-app with TypeScript and Tailwind. 3. Install @slack/bolt and wire up the Slack event handler at app/api/slack/route.ts. 4. Build CRUD task API routes at app/api/tasks/route.ts. 5. Build KanbanBoard.tsx with React Beautiful DND and Supabase Realtime subscription. 6. Add Slack slash command that opens a modal for task creation using Bolt modal API. 7. Wire Stripe checkout for team billing with webhook to update workspace tier in Supabase. 8. Seed a demo board in seed.ts so the PWA loads with sample data on first open. 9. Set up Vercel env vars and deploy preview branch. 10. Verify: install the Slack app in a test workspace, create a task via slash command, open PWA on an iPhone, move the card, confirm Slack posts the update.

Generated

April 25, 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.