Channels, threads, and real-time messages are a genuinely well-trodden build — websockets and a message table get you most of the way. What you can't rebuild in a weekend is the ten thousand hours other companies spent making their tools plug into it.
VIBE SCORE 88/100
The parts this build actually needs, each rated on its own — the average is the Vibe Score above.
| Landing page | 99 |
| CRUD database | 95 |
| User login | 92 |
| Realtime collaboration | 67 |
Two real costs, not just "free": the AI agent's own usage, and hosting once it's running. Both are estimated from this app's own effort rating and component list — see the assumptions on the method page.
| AI agent — with a subscription (Claude Pro/Max, Cursor, etc.) | $0 marginal |
| AI agent — pay-per-use API, no subscription | $43–$86 one-time |
| Hosting, once it's running | $5–$10/mo |
| Domain name, if you want your own | ~$12/yr |
Slack costs $8.75/mo, but hosting alone could run $5–$10/mo — that can eat the whole subscription saving before the agent cost even comes into it.
Don't feel like building it? These are already made, open-source, and free.
Borderline. Channels, threads, and real-time messages are a genuinely well-trodden build — websockets and a message table get you most of the way. What you can't rebuild in a weekend is the ten thousand hours other companies spent making their tools plug into it.
Slack costs $8.75/mo (about $105/yr) as of 2026-08. That's what a working rebuild would save you.
The app directory — every integration your team relies on (calendars, CI pipelines, ticketing) — doesn't come with you Enterprise-grade reliability at scale (message ordering, delivery guarantees across flaky connections) is a different tier of engineering than a personal build Huddles and screen-share need real-time video infrastructure, not just messaging — a much bigger add-on
Yes — Rocket.Chat, Zulip are open-source options worth trying before you build your own. Details are in the standard parts section on this page.
Slack compared directly against the products people actually weigh it up against — same build questions, different answers.
Curated sets Slack appears in.
Closest matches on the register — ranked by the build parts they share with Slack, not just by category.
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