Picture a small agency that runs each client in its own Slack channel. In month five, a client writes: “Did we agree to include the extra landing page, or was that going to be a separate quote?” The answer was settled in a thread roughly 120 days ago. Someone searches the channel, scrolls, and the thread does not come back. Chat is a conversation tool, and on the free plan Slack itself limits how much of that conversation you can read back.
The scenario is hypothetical, and so are the dates used below. The limits are not. They were checked on slack.com on 2026-09-29. They can change, they are not Watchdog data, and they are not on the re-verification schedule.
The question that arrives in month five
There are two separate limits here, and most confusion comes from merging them. One is about what you can read. The other is about what still exists. The next section quotes both from Slack’s own pages, so you do not have to take a summary on trust.
What Slack’s own pages say the free plan keeps
Both quotes below were fetched directly from slack.com on 2026-09-29. The pricing page shows the Free plan as “Free forever”. This post quotes no currency figures, because the page localises them.
| Source | What it says | What it means for a thread |
|---|---|---|
| Pricing page, Free column | “90 days of message history. Messages are saved and searchable for 90 days. Upgrade to access the previous 12 months messages.” | Past 90 days, messages are no longer searchable on the free plan. Slack points to upgrading for the previous 12 months. |
| Help article on free version limits | “On the free version of Slack, you’ll be limited to the most recent 90 days of message and file history, and all data in your workspace that’s more than one year old will be deleted. When you upgrade, your messages and files beyond the 90-day limit will be revealed.” | Two events. Past 90 days, history is limited and revealed on upgrade. Past one year, data is deleted. |
| Pricing page, compliance row | “Free Slack deletes data after one year. Paid subscriptions keep it for life by default, with adjustable settings.” | Retention on a paid plan is a default that can be adjusted, not a guarantee of permanence. |
The distinction to hold onto is this. Data between 90 days and one year old is described as limited and later revealed, so it is hidden, not gone. Data past one year is described as deleted, and the same help article says that after a year on the free version data is “permanently deleted”.
Walking one decision through the calendar
This is an illustration with hypothetical dates, not a real account. Say a client approves an extra deliverable in a channel thread, and the approving message has a screenshot attached. Using only Slack’s two thresholds, here is the state of that decision over time.
Day 30. The message is inside the 90 day window. It is searchable, and so is the attached file, since Slack’s wording covers “message and file history”.
Day 90 and just after. The message crosses the first threshold. Per the pricing page, messages are saved and searchable for 90 days, so from here the thread stops appearing in search on the free plan.
Day 150. This is the trap. Under Slack’s help article the message and its file are beyond the 90-day limit but inside one year, so they are not deleted. They are hidden, and the article says they are revealed on upgrade. The data is not gone, but the person who needs it cannot read it, and the fix depends on paying. In the scene from the opening, this is the day the client’s question lands.
Day 400. The message is more than one year old. On the free version, Slack says data at this age will be deleted. Reading the article’s wording, an upgrade at this point reveals what is left beyond the 90 day limit, and it does not bring back what has already been deleted. Treat any claim of recovery as unproven: [EVIDENCE NEEDED: a Slack page stating whether deleted free-plan data can be restored after upgrading].
What upgrading does and does not fix
Slack’s help article says that when you upgrade, messages and files beyond the 90-day limit will be revealed. For a thread at day 150, that is the relevant fix. For a thread at day 400 on a workspace that has been on the free version throughout, the same article describes the data as deleted, and nothing on the page says upgrading returns it.
A paid plan that keeps data by default is a retention setting. It is not a client-facing record. Someone on your team still has to find the right thread, read it, and show it to a client who may not be in the workspace, and that depends on the person who made the decision still being around to point at it. This post makes no comparison with other tools and does not rank or recommend any plan.
Who in the channel can actually read it
Slack’s pages state these limits at the workspace level: “all data in your workspace”. So the plain reading is that they shape what your agency team sees when it searches. Slack’s pages do not address what a client keeps in their own email or notes, and this post will not speculate about it.
The same help article has one further point that matters for client channels. It says that once you are on the free version, Slack Connect channels will disconnect, and that existing guest accounts will be deactivated and would have to be reactivated as full members. That is written in the context of downgrading from a paid subscription. How the history limit itself applies to Slack Connect or external guests is not stated on any page read for this post: [EVIDENCE NEEDED: a Slack help page stating how the 90 day limit applies to Slack Connect channels and guest accounts].
If the seat side of client collaboration is your concern, the site has a separate piece on who counts as a billable seat.
A routine for moving decisions out of chat
The routine below does not depend on any tool or plan.
- Define what counts as a decision. Four kinds are enough to start: a scope change, an approval, a price, and a deadline. Everything else stays in chat.
- Write it in one dated line within two working days. Pick a stated number and stick to it. The line carries five things: the date, who decided, what was decided, the thread it came from, and what it replaces. For example: “2026-03-12. Client contact approved the second landing page as an add-on to the retainer. Source: the channel thread of that date. Replaces the earlier scope of one page.”
- Put the line somewhere that is not the chat. The destination can be a shared document, a project tracker, or the client email thread.
- Send it back for a one-word confirmation. The client replies “confirmed” or corrects it. The same problem shows up when a client approves a post by text.
- Log where each record lives. A short index of client, date, and location is enough, so a new team member can find a decision without asking who made it.
- Review the log at each retainer renewal.
Two checks belong next to the routine. First, before downgrading or leaving a workspace, Slack’s help article points to workspace analytics for an overview of how many messages and files will be hidden by the 90-day limit and how much data will be permanently deleted after a year. Second, on export: Slack’s compliance table lists data exports for all messages, described on the pricing page as available to workspace owners and admins, but the columns that include it were not resolved from the page text read here. Check which column includes your plan before relying on export as your backup. The site’s companion piece covers what you can export before a tool shuts down.
What this post does not cover
The limits were read from slack.com on 2026-09-29 and can change. This is not Watchdog data and it is not on the re-verification schedule. The post makes no recommendation about which chat plan to buy, and it is a workflow piece, not legal advice about record-keeping.
followedapp is published by the team behind RecurPost, and RecurPost is a covered vendor under the same rules as every other vendor.
Before your next renewal
Pick your two most active client channels this week, write the dated one-line record for the last decision in each, and send it for confirmation.
FAQ
Does Slack delete data on the free plan?
Slack’s help article says that on the free version “all data in your workspace that’s more than one year old will be deleted”, and that data is “permanently deleted” after a year. That is separate from the 90 day limit, where history is hidden and, per the same article, revealed on upgrade.
If I upgrade, do I get the hidden messages back?
Slack’s help article says that when you upgrade, messages and files beyond the 90-day limit will be revealed. Data already deleted past one year is a different matter, and no page read for this post says it can be restored: [EVIDENCE NEEDED: a Slack page stating whether deleted free-plan data can be restored after upgrading].
Sources
- Slack pricing page, Free column and compliance row, fetched 2026-09-29
- Slack help article on free version limits (message and file history, workspace analytics, Slack Connect, guests), fetched 2026-09-29
- Slack help article on subscriptions and export, fetched 2026-09-29