Should my company build its own chat app?

Almost never for internal use: existing chat tools are cheap and good. Building makes sense when chat is part of a product you sell, such as messaging between your customers and their clients inside your platform.

Can I add chat to my existing app instead?

Yes. Embedding chat in your product, often with a chat API provider, is a far smaller project than a standalone team chat SaaS and usually the right call.

Is this what Slack spent to build its app?

No. It is Eltherion's estimate for building a comparable first version today. It says nothing about what Slack spent, and Eltherion is not affiliated with Slack. A product at that company's scale has years of work and teams behind it that no MVP includes.

How can I lower the cost?

Launch with fewer integrations, one market and one platform, and leave the full-platform features until users ask for them. The adjustable calculator shows how each choice moves the range.

Productivity and SaaS tools

How much does it cost to build an app like Slack?

By Nick McCandless, founder of EltherionUpdated October 30, 2026

Short answer

Eltherion prices an MVP of an app like Slack, a team chat SaaS, at $46k to $125k. A full platform with the features listed below runs $83k to $221k. These are Eltherion's own estimate ranges for building a comparable product, not what Slack spent; your fixed price comes after a free scoping call, and small, tightly scoped work starts as low as $1,000.

Adjust this estimate in the calculator Get a fixed quote

An app like Slack gives each company a workspace with channels, direct messages, threads and file sharing, all updating in real time. As SaaS, each customer company's data is kept separate and billed by plan.

What an MVP of an app like Slack costs, feature by feature

The first version below is the smallest product people could actually use. Core features are covered by the base price for a SaaS product; each outside service the app connects to, and each add-on, adds its own line.

Eltherion estimate for an app like Slack, MVP (updated October 30, 2026)
Line item	What it covers	Estimate
Core SaaS product (MVP)	Workspaces, channels and direct messages, Search, File sharing	$35k to $95k
Separate company workspaces	Each customer's data and admins kept apart	$5k to $15k
File storage	Store uploads with a storage service	$2k to $5k
Push and email notifications	Mentions and unread messages	$2k to $5k
Subscription billing	Plans and payments	$2k to $5k
Total		$46k to $125k

Workspaces, channels and direct messages: Real-time messaging with threads.
Search: Find messages and files.
File sharing: Upload and preview files.

What drives the cost of an app like Slack

Real-time messaging that stays fast and reliable is the core engineering work.
Multi-company data separation and admin controls make it a SaaS build.
Enterprise features (single sign-on, retention policies) come with bigger customers.

Full platform: $83k to $221k

The full-platform tier prices the same app at full-platform scope ($63k to $171k for the core) plus these additions:

Single sign-on: Enterprise login ($5k to $10k).
Integrations platform: Bots, webhooks and an app directory (part of the full-platform core).
Voice and video huddles: Calls through a real-time media provider ($2k to $5k).
Search service: Fast search across large message histories ($2k to $5k).

Most products should not build this tier up front. Ship the MVP, see what users actually do, and add the pieces that earn their place. Open the full-platform estimate in the calculator.

Running costs after launch

Maintenance and small improvements: $8k to $23k a year for the MVP (18% of the build, a planning assumption).
Hosting: about $7k a year (a planning estimate; heavy usage costs more).
Three-year total for the MVP, build included: $92k to $214k.
Card payments: Stripe's standard US rate is 2.9% + 30¢ per successful domestic card transaction (checked October 30, 2026); other providers price differently.

Each integration also has its provider's own usage fees (maps, messaging, video, AI models), which depend on how much the app is used.

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Frequently asked questions

How much does it cost to build an app like Slack?: Eltherion prices an MVP of an app like Slack, a team chat SaaS, at $46k to $125k, and a full platform at $83k to $221k. These are Eltherion's estimate ranges from its published pricing model; your fixed price comes after a free scoping call. Small, tightly scoped work starts as low as $1,000.
Should my company build its own chat app?: Almost never for internal use: existing chat tools are cheap and good. Building makes sense when chat is part of a product you sell, such as messaging between your customers and their clients inside your platform.
Can I add chat to my existing app instead?: Yes. Embedding chat in your product, often with a chat API provider, is a far smaller project than a standalone team chat SaaS and usually the right call.
Is this what Slack spent to build its app?: No. It is Eltherion's estimate for building a comparable first version today. It says nothing about what Slack spent, and Eltherion is not affiliated with Slack. A product at that company's scale has years of work and teams behind it that no MVP includes.
How can I lower the cost?: Launch with fewer integrations, one market and one platform, and leave the full-platform features until users ask for them. The adjustable calculator shows how each choice moves the range.

How we priced this

Every number on this page comes from Eltherion's software development cost calculator: a base range for the product type, multiplied by scope, plus a fixed range for each integration and add-on. The method is published on the cost methodology page. The feature list describes a typical comparable product; Eltherion is not affiliated with Slack.