Slack Review 2025: The App I Love to Hate and Hate to Love

Last Tuesday I Had 147 Unread Notifications Before 10 AM

I know this because I counted. One hundred and forty-seven. Spread across 23 channels, 8 thread replies, 4 direct messages, and whatever that bot notification from Jira was about. I hadn't even finished my coffee. The red badges on my sidebar looked like a Christmas tree. And the thing is, maybe 12 of those 147 notifications required any action from me at all. The rest were channel chatter, bot noise, people reacting to messages with emoji, and @here mentions in channels I forgot I was in.

This is Slack in 2025. The most polished, most capable, most infuriating team communication tool ever built. I've been using it daily for seven years now across four companies, and my relationship with it is genuinely complicated. I check it first thing in the morning and last thing at night. I've built custom bots for it. I've written Slack API integrations. I also regularly fantasize about deleting it from my dock and never looking at it again.

So this isn't a review where I list features and tell you it's good. You probably already know it's good. What I want to talk about is the patterns -- how Slack shapes the way teams actually communicate, the habits it creates, and whether those habits are net positive or net negative for getting work done.

The Channel Problem (Which Is Actually a People Problem)

Slack's organizing principle is channels. You create one for each topic, project, team, or purpose. In theory this is elegant -- conversations are organized, searchable, and discoverable. In practice, every organization I've worked at has had a channel proliferation problem.

It starts innocently. You have #engineering, #design, #product. Makes sense. Then someone creates #engineering-frontend and #engineering-backend. Fine. Then #project-falcon, #project-eagle, #project-condor. Sure. Then #random, #watercooler, #pets, #food, #music, #fitness, #memes. Then #eng-deploys, #eng-oncall, #eng-incidents, #eng-platform, #eng-platform-observability. Before you know it, your sidebar has 60 channels and you're spending cognitive energy deciding which channel a question belongs in rather than just asking the question.

The fix for this isn't a Slack feature. It's organizational discipline. Mute channels heavily. Use channel sections in the sidebar to group what matters. Set notification preferences per channel (I have maybe 5 channels on "all messages" and everything else on "mentions only"). These tools exist in Slack and they work well. Most people just don't use them, which is a user education problem more than a product problem.

Threads: The Feature That Saved Slack (And Also Created Thread Hell)

Slack's threading is the best implementation of threaded conversations in any chat tool. Period. When someone replies in a thread instead of the main channel, it keeps the channel clean while allowing detailed discussion. You can follow specific threads, see all your active threads in one view, and get notified only about threads you care about.

But threads have also created a new problem: important decisions getting buried inside threads that not everyone follows. Someone asks a question in #engineering. A discussion unfolds in a thread. Twenty messages later, the team decides to change the API spec. But the only people who saw that decision are the six who happened to be in the thread. Everyone else sees a message from two days ago with "23 replies" and has to decide whether to click into it.

The "Also send to #channel" checkbox on thread replies helps with this, but it's opt-in and most people forget to use it. I've started a habit of posting a summary in the main channel after any significant thread discussion: "FYI, we decided X in the thread above. See thread for context." It's manual and slightly annoying but it prevents the alternative, which is decisions that nobody outside the thread knows about.

Search: The Reason Slack Calls Itself a "Searchable Log of All Communication"

Slack's search is genuinely excellent and it's the feature that makes the whole thing worthwhile. Every message, file, link, and snippet is indexed and searchable with filters for channel, person, date, file type, and reactions. In a workspace with hundreds of thousands of messages, I consistently find what I need in seconds.

The search modifiers are powerful: from:@arjun in:#engineering after:2024-12-01 has:link narrows down results fast. I use this daily. When someone asks "didn't we discuss the API rate limiting approach somewhere?" -- instead of trying to remember which channel, which week, which conversation -- I just search "rate limiting" filtered by the relevant timeframe and find it.

This is Slack's real value proposition, not as a chat app but as an institutional memory. Every conversation is preserved and findable. When a new engineer joins the team, they can search the history to understand past decisions rather than asking people to retell them. That's worth a lot. It's also why the free plan's 90-day history limit is such a significant downgrade -- you're not just losing old messages, you're losing your searchable knowledge base.

The Integration Ecosystem: Why You Can't Leave

This is the moat. Over 2,600 integrations. GitHub sends PR notifications. Jira updates arrive in real time. PagerDuty alerts page through Slack. Vercel deployments post their status. Sentry errors appear with stack traces. Google Calendar reminds you about meetings. Figma shows design previews. Every tool in your stack can pipe its output into Slack, and most of them can accept commands back from Slack.

For engineering teams specifically, the integrations are the killer feature. I have a channel where every merged PR, every deployment, and every error alert appears. During an incident, Slack becomes the war room -- PagerDuty triggers an alert, a dedicated incident channel is auto-created, the right people are pulled in, and post-incident notes are captured in thread. Try doing this in Microsoft Teams and tell me how it goes. (Actually, don't. I already know. It's worse.)

The integration ecosystem is also why switching away from Slack is so hard. It's not that Slack is irreplaceable as a chat app. It's that you've wired your entire toolchain into it, and unwiring that is a project nobody wants to do.

Huddles, Clips, Canvas: The Features That Might Not Be for You

Huddles are lightweight audio/video calls you can start in any channel or DM. The idea is right -- sometimes a five-minute voice call resolves something that would take thirty messages. In practice, I use Huddles maybe twice a week for quick pairing sessions or "hey can you look at this for a second" moments. The audio quality is fine. The video is fine. Screen sharing works. It's not Zoom, but it's not trying to be. For quick synchronous conversations that don't warrant a calendar invite, Huddles are great.

Clips let you record short audio or video messages and drop them into channels or DMs. The async communication use case is real -- I've used clips to explain code changes, walk through designs, and give context on PR reviews. It's faster than writing a long message and more nuanced than text. But I'll be honest: most of my team doesn't use them. There's a social awkwardness to recording a video of yourself talking at your screen that text doesn't have. Good feature, adoption problem.

Canvas is Slack's built-in docs feature. It's fine for channel-level documentation -- meeting notes, project briefs, reference links. It's not replacing Notion or Google Docs for anything substantial. But having a pinned Canvas in each project channel that lists the relevant links, decisions log, and team contacts is genuinely useful. It solves the "where did we put that?" problem for channel-specific knowledge.

The Elephant in the Room: Microsoft Teams

Everyone brings up Teams, so let me address it directly. Microsoft Teams has more users than Slack. This is true. Teams is free with Microsoft 365. Also true. Teams has video calling that's better than Huddles. True again.

But using Teams after using Slack feels like going from an iPhone to a flip phone. The threading is worse. The search is worse. The UI is cluttered with features you didn't ask for. The integration ecosystem for non-Microsoft tools is shallow. The notification system is less configurable. Everything takes one more click than it should. It's the difference between a product that was designed around messaging and a product that had messaging bolted onto an enterprise suite.

That said, if your company already pays for Microsoft 365 and budget is the primary concern, Teams is a completely rational choice. You're already paying for it. It integrates tightly with Outlook, SharePoint, and OneDrive. For organizations embedded in the Microsoft ecosystem, the total-cost argument for Teams is hard to beat. Just know that you're getting a worse messaging experience in exchange for a better spreadsheet integration.

What Slack Costs Your Company (Per Person, Per Year)

The free plan: $0. You get 90 days of message history, 10 app integrations, one-on-one Huddles. Fine for a small team figuring out if Slack is for them. The 90-day history limit is aggressive though -- after three months your old messages vanish into the void. That's a real loss for institutional knowledge.

Pro at $7.25 per person per month (billed annually): unlimited history, unlimited integrations, group Huddles, custom user groups. This is where most teams land. For a 20-person team, you're at $1,740/year. Not cheap, but the unlimited history and integrations make it a different product from the free tier.

Business+ at $12.50/person/month: SSO, compliance exports, 24/7 support. Enterprise needs. If your compliance team is asking about data exports or your IT team needs SAML, you're here.

Enterprise Grid: call sales, bring your finance team. Unlimited workspaces, HIPAA compliance, dedicated support, custom contracts. For large organizations with complex needs.

For the record: a 50-person company on Pro pays $4,350/year. On Business+, that's $7,500. Those numbers make budget-conscious decision makers look at Microsoft Teams (free with their existing M365 licenses) and ask hard questions. And honestly? Those are fair questions to ask.

Is There Actually Something Better?

I've tried. Genuinely. Discord is fun and the voice channels are better, but it lacks enterprise features and your compliance team will have questions. Google Chat is getting better but the threading is rudimentary and the integration ecosystem is shallow outside Google Workspace. Mattermost is open source and self-hosted, which appeals to certain organizations, but the polish and app ecosystem aren't comparable. Zulip has a unique topic-based threading model that's arguably more organized than Slack's channels, but the UI feels stuck in 2018 and adoption is tiny.

The honest answer is no. There isn't something clearly better for the overall team communication experience. There are alternatives that are cheaper, or that do specific things better, or that avoid specific problems Slack has. But the total package -- the UI polish, the search, the integrations, the threading, the API, the cross-platform consistency -- nobody matches it across all those dimensions simultaneously.

That's not a ringing endorsement. It's more of a resigned acceptance. Slack is the best option, not because it's great at everything, but because nobody else is good enough at enough things to justify the switching cost.