What does it cost to build an app like Slack?
Sample range · freelance
$35k–$79k
An agency would be $62k–$175k for the same scope. This is a pre-computed sample, not your estimate. Your version is probably smaller.
Where the money goes
Why this kind of app is expensive
Real-time messaging at team scale needs a persistent connection layer that stays in sync across every device someone is logged into, not a request-response API.
Searching years of message history fast requires real indexing infrastructure, not a database query.
An integrations and bot platform means a public API other companies build against and have to keep stable, and enterprise buyers expect admin controls and compliance exports before they sign.
The cheapest honest version of this idea is single workspace, no bot integrations, no compliance exports. That lands nearer $24k–$55k.
Your app is not Slack. Get the range for what you are actually building.
Not open yet
Launching this weekend.
The free range, the $79 spec and the $199 execution pack all open then. Nothing to sign up for — come back and paste your idea.
Same maths, other archetypes