How Much Does It Cost to Build an App Like Slack?
Team chat is live messaging plus everything around it: workspaces, permissions, files, search and notifications. Here is what an MVP of an app like Slack needs, what each part costs on our price list, and what it costs to run.
Test version: $7,000, about 35 days: channels and direct messages that update live. Lean web MVP: $11,750, 45 to 50 days: adds workspaces with roles, file sharing, search, email notifications and paid plans. Version 1 with iOS and Android apps: $17,750, 9 to 11 weeks.
All three are fixed prices from our published price list. For the lean scope, a typical agency quote runs $77,000 to $204,000 or more by our estimate (see the MVP development cost guide). At 400 users, our worked example puts running costs at about $157 a month, payment fees included.
One honest point first: if your team just needs chat, use Slack. This page is for founders building chat into a product for a specific market, such as a client portal, a community for one profession or a tool for one industry, where the conversation is part of what customers pay for. Other app types are in our app cost breakdowns.
What an MVP of an App Like Slack Actually Needs
The core loop: someone posts in a channel, everyone in it sees the message within a second, people reply, and anyone can come back later and find what was said. If a message is late, missing or out of order, nothing else matters.
- Workspaces and invites. A team signs up, invites members by email, and admins control who joins. Guest access to selected channels is worth having early if your users work with clients.
- Channels and direct messages. Public and private channels, plus one-to-one conversations.
- Live delivery. Messages appear without refreshing, with unread counts and who is online.
- Files. Images and documents shared into a conversation, with previews.
- Search. Find a message or file by keyword, by channel, person and date, and only within what that user may see.
- Notifications. An email when someone is mentioned or has unread messages while away.
- Paid plans. A free tier and per-seat plans with a billing portal.
What the real Slack has that version one does not need
Going by Slack's own pricing page:
- Huddles. Slack's audio and video calls, with group huddles on paid plans. Live audio and video is a project of its own; link to an existing video tool at first.
- Slack Connect. Channels shared with other organizations, up to 250 on the Pro plan. Permissions across companies double the security work, so wait until customers ask.
- Workflow Builder and app integrations. Slack's free plan allows up to 10 apps. Version one needs at most a webhook: a URL another tool can post messages to.
- SAML SSO and full message exports. Slack keeps both for its Business+ plan. They matter when IT departments buy.
- AI summaries and AI search. On Slack's paid plans. Add AI features later, at +$2,500 on our price list, once you know what users would summarize.
Slack's free plan also shows only 90 days of message history, while paid plans keep it all: history limits are a pricing lever, so set yours on purpose.
How Slack Started
Slack began as a side effect. In its 2019 filing to go public, the company wrote that it created Slack "initially as an internal tool to help our own team stay on the same page," because the team was frustrated with email: "What we needed did not exist. So we built it." The company was incorporated in 2009 as Tiny Spec, Inc. and renamed Tiny Speck later that year.
According to Britannica, work on the Slack app began in 2012, a preview release appeared in August 2013, and the go-to-market release followed in February 2014. So it ran inside one real team, then a preview group, before it was sold widely. For your MVP: a handful of teams using it every working day tell you more than a wide launch.
Price Breakdown: Three Versions, Line by Line
Every line is a fixed price from our published price list; build days are working days. The calculator shows a range and a calendar timeline because details such as screen count come out on a call, which turns the range into one fixed quote.
1. Test version with live channels: $7,000, about 35 days
| Item | What it covers | Price | Build days |
|---|---|---|---|
| Base MVP | Sign-up and login, one workspace, channels and direct messages, message history, database, Stripe checkout or a waitlist, basic admin view, landing page, deployment, 30 days of support | $5,000 | 20 |
| Real-time | Messages appear without refreshing, with unread counts and who is online | +$2,000 | 3 |
| Total | $7,000 | 23 |
Calculator estimate: $7,000 to $7,500, about 35 days. Open this build in the calculator
What you do by hand in this version. You set up each pilot team's workspace and send the invites yourself. Files are shared as links to Google Drive or Dropbox. There is no search, so pilots scroll, and no email alerts, so you nudge quiet teams yourself. Paying teams use a one-off Stripe checkout or an invoice. None of that matters for a test, which asks one question: will a few teams move their daily conversation into your product and stay for a month?
2. Lean web MVP: $11,750, 45 to 50 days
| Item | What it covers | Price | Build days |
|---|---|---|---|
| Base MVP | As in the test version: sign-up, channels and direct messages, history, database, admin view, landing page, deployment, 30 days of support | $5,000 | 20 |
| Real-time | Live messages, unread counts and online status | +$2,000 | 3 |
| Teams and roles | Workspaces, email invites, admin, member and guest roles, private channels | +$1,500 | 2 |
| File processing | Image and document uploads in conversations, with previews | +$1,000 | 1 |
| Search and filters | Search messages and files by channel, person and date, limited to what each user may see | +$750 | 1 |
| Email automation | Invite emails, plus emails for mentions and unread messages while someone is away | +$500 | 1 |
| Subscription billing | Per-seat plans, a trial, upgrades and a billing portal | +$1,000 | 2 |
| Total | $11,750 | 30 |
Calculator estimate: $12,000 to $14,000, 45 to 50 days. Open this build in the calculator
This is the version to charge for: teams can run on it without you in the loop.
3. Version 1 with iOS and Android apps: $17,750, 9 to 11 weeks
| Item | What it covers | Price | Build days |
|---|---|---|---|
| Everything in the lean MVP | Version 2 above | $11,750 | 30 |
| Web + native mobile | iOS and Android apps built with React Native | +$6,000 | 15 |
| Total | $17,750 | 45 |
Calculator estimate: $18,000 to $21,500, 9 to 11 weeks. Open this build in the calculator
Chat is one of the few products where native apps earn their cost early, because people expect a push notification when someone messages them. If your users work at desks, launch on the web first; a web app also works in a phone browser. Selling upgrades inside an iOS app falls under Apple's in-app purchase rule (guideline 3.1.1), so read Apple's current guidelines before you put upgrade screens in the app.
Running Costs After Launch
Assumptions for the lean web MVP: teams of 20 paying $6 per seat a month ($120 per team); each member sends 40 messages per working day over 22 working days; each message reaches 6 colleagues who are online; and each member gets 2 notification emails per working day. We price two sizes, 20 teams (400 users) and 100 teams (2,000 users). Prices checked November 2026.
Supabase counts a broadcast message as one sent plus one per client that receives it, so each chat message counts as 1 + 6 = 7. At 400 users that is 400 × 40 × 22 = 352,000 messages sent and 352,000 × 7 = 2,464,000 Realtime messages a month, inside the 5 million included in Supabase Pro.
| Item | 20 teams (400 users) | 100 teams (2,000 users) |
|---|---|---|
| Supabase Pro: database, sign-in, files, real-time (from $25) | $25 | $25 |
| Realtime messages above 5 million ($2.50 per million) | 2.46 million: $0 | 12.32 million: 7.32 × $2.50 = $18.30 |
| Peak connections above 500 ($10 per 1,000) | At most 400: $0 | 1,500 at peak, 1,000 over: $10 |
| Hosting (Vercel Pro) | $20 | $20 |
| Email (Resend Pro: 50,000 included, then $0.90 per 1,000) | 17,600 emails: $20 | 88,000 emails: $20 + 38 × $0.90 = $54.20 |
| Stripe: 2.9% + 30¢ per charge plus 0.7% Billing, on $120 a team | 20 × $4.62 = $92.40 | 100 × $4.62 = $462 |
| Total | $157.40 | $589.50 |
Revenue: 20 × $120 = $2,400 and 100 × $120 = $12,000 a month. Stripe per team: $120 × 2.9% + $0.30 + $120 × 0.7% = $3.48 + $0.30 + $0.84 = $4.62.
For context, Slack's own Pro plan is $8.75 per user per month billed monthly, or $7.25 billed annually. The example assumes files stay under Supabase Pro's 100 GB of storage and downloads under its 250 GB of monthly egress (data sent out); above those it lists $0.0213 per GB stored and $0.09 per GB. With native apps, add Apple's developer program at $99 a year and Google Play's one-time $25 fee; Firebase Cloud Messaging, a common push service, states there is no cost to using it.
Timeline: The Lean MVP Week by Week
The lean MVP is 30 build days, which the calculator shows as 45 to 50 days:
- Week 1: scope signed, data model for workspaces, channels and messages, core screens designed, skeleton deployed.
- Week 2: sign-up, workspaces, invites and roles; channels and direct messages saved to the database.
- Week 3: live delivery, unread counts, online status, and catching up after a dropped connection.
- Week 4: file uploads with previews, and search across messages and files with access checks.
- Week 5: email notifications, per-seat plans in Stripe, the admin view.
- Week 6: permission and load testing (can a member ever see a private channel they are not in?), landing page.
- Week 7: launch, handover of the source code and documentation, and 30 days of support.
What a SaaS product needs on day one, beyond chat, is covered in our SaaS MVP guide.
What Makes a Team Chat App Hard
- Delivery you can trust. Messages must arrive once, in order, and survive a phone switching from Wi-Fi to mobile data. That takes message IDs, retries and a catch-up step after reconnecting, or people see gaps and duplicates.
- Permissions everywhere. Private channels and guests mean every query has to check access: search results, file links, notification emails, even unread counts. One missed check in search leaks a private conversation, so test access rules as hard as features.
- Notifications without noise. One message can reach someone in the browser, by email and on a phone. Decide who is notified, where and when, or people mute your product. This is design work as much as code.
- Data that only grows. Messages and files pile up every day. Plan retention and export from the start; Slack itself limits free history to 90 days and keeps full message exports for Business+.
When We Are Not the Right Choice
If your team needs a place to talk, buy Slack or another chat tool: at $7.25 per user per month billed annually, no custom build can match it for one team. Build when chat is part of a product you sell to a specific market.
We are also the wrong fit if version one must have end-to-end encryption with independent audits, on-premises installs or connections to other chat networks; if you are answering an enterprise RFP that needs 50 or more engineers; or if your product is really a consumer mobile game with chat inside. Our fixed-price MVP model suits a focused chat product, not open-ended infrastructure. If chat is one feature of a booking or AI product, see the scheduling app and AI chat app breakdowns.
After launch, threaded replies, integrations and AI summaries are typical work for our Growth Partner retainer, from $5,000 a month for 60 hours.
Get a Fixed Price for Your Slack-Style App
Tell us who talks to whom in your product and what they share. On a free call we will pick the version that fits, fix the price and estimate your monthly running costs.
Book a Free Call →Frequently Asked Questions
How much does it cost to build an app like Slack?
At minidev.pro, a lean web MVP of an app like Slack costs $11,750 fixed: the $5,000 base plus real-time messaging, teams and roles, file sharing, search, email notifications and subscription billing. A test version with live channels only is $7,000, and adding iOS and Android apps brings it to $17,750. By our estimate, a typical agency quote for the lean scope is $77,000 to $204,000 or more.
How long does it take to build an app like Slack?
45 to 50 days for the lean web MVP, which is 30 working days of build time. The live-channels test version takes about 35 days, and the version with native iOS and Android apps takes 9 to 11 weeks, because the apps add 15 build days. Most of the time beyond a basic MVP goes into live delivery, permissions and search.
Do I need native mobile apps for a team chat MVP?
Not for a pilot. A web app works in a phone browser, and teams at desks will mostly use the web version. Add native apps when users expect push notifications on their phones; on our price list that is +$6,000 and 15 build days. Firebase Cloud Messaging, a common push service, states there is no cost to using it, while Apple charges $99 a year for a developer account.
How much does it cost to run a chat app like Slack each month?
About $157 a month at 400 users and about $590 at 2,000 users in our worked example, Stripe fees included. Supabase Pro, from $25 a month, includes 5 million real-time messages and 500 peak connections, which covers the smaller case; above that it charges $2.50 per million messages and $10 per 1,000 connections. Hosting and email add $40 to $75.
Why build a chat app when Slack already exists?
Build only when chat is part of a product you sell, not the tool your own team uses. Examples: messaging inside a client portal, a community for one profession, or chat with workflows for one industry. If you just need team chat, Slack's Pro plan at $7.25 per user per month billed annually is far cheaper than any build.
Sources
All outside pages checked November 2026. Prices and plans change, so check each provider's page before you budget.
- Slack Technologies, Form S-1 registration statement, 2019 (Slack created as an internal tool; frustration with email; public launch in 2014; incorporated in 2009 as Tiny Spec, Inc., renamed Tiny Speck): sec.gov/Archives/edgar/data/1764925/000162828019004786/slacks-1.htm
- Encyclopaedia Britannica, Slack (work on the app began in 2012; preview release in August 2013; go-to-market release in February 2014): britannica.com/technology/Slack
- Slack, Pricing (free plan with 90 days of history, up to 10 apps and 1:1 huddles; Pro at $8.75 per user per month monthly or $7.25 annually; Slack Connect with up to 250 organizations; Workflow Builder; SAML SSO and full message exports on Business+; AI features): slack.com/pricing
- Supabase, Pricing (Pro from $25 a month; 100 GB storage, then $0.0213 per GB; 250 GB egress, then $0.09 per GB; 500 Realtime peak connections, then $10 per 1,000; 5 million Realtime messages, then $2.50 per million): supabase.com/pricing
- Supabase Docs, Manage Realtime Messages usage (a broadcast counts as one message sent plus one per receiving client): supabase.com/docs/guides/platform/manage-your-usage/realtime-messages
- Stripe, Pricing (2.9% + 30¢ per domestic card charge; Billing at 0.7% of billing volume): stripe.com/pricing
- Vercel, Pricing (Pro at $20 a month per developer seat): vercel.com/pricing
- Resend, Pricing (Pro at $20 a month for 50,000 emails; extra emails $0.90 per 1,000): resend.com/pricing
- Firebase, Cloud Messaging ("There's no cost to using Cloud Messaging"; iOS, Android and web): firebase.google.com/products/cloud-messaging
- Apple Developer, Become a member (99 USD per membership year): developer.apple.com/programs/enroll
- Google Play Console Help, Get started with Play Console (US$25 one-time registration fee): support.google.com/googleplay/android-developer/answer/6112435
- Apple, App Review Guidelines (3.1.1, in-app purchase): developer.apple.com/app-store/review/guidelines
- minidev.pro, MVP cost calculator price list: minidev.pro/mvp-cost-calculator