CHI Company Investigation · Productivity Software
Slack
Slack Traded Searchable Memory for an Operating System
Channels · Search · Canvas · Workflows · AI · Agents · Salesforce
Standard company investigation · No score assigned · Research closed 3 October 2026
Not a simple decline story. More value and more control arrived together.
Slack came out of a failed video-game company with an unusually simple proposition: put a team's conversations, files and knowledge in one searchable place. For years its public prices and its free-plan boundary barely moved. Under Salesforce it became far broader — documents, workflows, AI, agents, enterprise search and deep CRM integration — while also introducing permanent deletion on the free plan, bundling AI into a higher-priced tier and tightening control over how outside applications may retain or index customers' Slack data. This page sets out both halves.
2014 Searchable team memory
Channels, files and integrations feeding one searchable history.
→2026 AI work platform
- AgentsSlackbot · Agentforce · partner agents
- AISummaries · search answers · enterprise search
- AutomationWorkflow Builder
- DocumentsCanvases · lists
- CRMSalesforce channels and records
- Channels + searchThe original product, still underneath
More value What customers gained
A much larger product, at a Pro price that is lower in real terms than at launch.
Threads, Slack Connect, huddles, canvases, automation, AI search and agents were all added. Pro's list price has risen once in twelve years and is approximately 23–24% cheaper after inflation than in 2014. Fair Billing still credits inactive seats, and cancellation is self-service.S7S8S9
More control What Slack and Salesforce gained
More say over history, packaging and who may hold a copy of customer data.
Free-plan history moved from a 10,000-message view to a 90-day window in 2022, and content older than one year has been permanently deleted since August 2024. AI went from an optional add-on into a Business+ plan priced approximately 20% higher. API terms now bar third-party commercial apps from keeping persistent indexes of customers' Slack data.S4S5S15
Both columns describe the same company. The evidence supports neither the view that Salesforce ruined Slack nor the view that Slack only got better.
01Origin
The Failed Game Is Real. The Story Is More Complicated.
The popular account — a failed video game that became a messaging company — is directionally accurate but technically oversimplified. The company and the failed game are real and causally linked to Slack. The product was not the game, not a feature of the game, and not a finished internal tool that was simply repackaged.
- 2002–2005 · the first attempt
Ludicorp is founded in Vancouver to build Game Neverending, a browser-based multiplayer game. The game is shelved as a prototype when it cannot be financed; the photo-sharing service Flickr is launched on its technology in 2004, and Yahoo acquires the company in 2005.T21
- 2009 · Tiny Speck
Stewart Butterfield and former Flickr colleagues including Cal Henderson incorporate Tiny Speck to build a second game, Glitch.S1
- September 2011 – December 2012 · Glitch
Glitch launches publicly in September 2011 and returns to beta two months later. Its closure is announced in mid-November 2012, citing an audience too small to sustain it, and the game world closes on 9 December 2012.T3 By the founder's later account, about $5.5 million of funding remained, which is what made a second product possible.T21
- Late 2012 – 2013 · the rebuild
A smaller team begins building a commercial communication product modelled on how the staff had worked. A preview release is announced in August 2013; the public launch with paid plans follows in February 2014, and Tiny Speck is renamed Slack Technologies.T1T2S1
What the team had actually assembled
- A standard IRC server with channels by function
- Persistent conversation history, logged to a database
- Search over that history
- File sharing posted into a channel
- System-event feeds — sign-ups, support requests, deploys
What Slack was not
- Not the game itself. Glitch closed; Slack was built afterwards.
- Not a Glitch feature. The precursor was staff tooling, not in-game chat.
- Not a finished internal product repackaged. It was several scripts around IRC; by the team's own later account, Slack was a fresh build that kept the lessons.T4
The distinction matters. Each of Slack's defining ideas — persistent channels, searchable history, files in the stream, machine-generated messages — is visible in that patchwork. Every description of it is retrospective and comes from insiders, and whether any of the game's own messaging code was reused is not established.
02What Slack originally sold
Slack Wasn't Really Selling Chat
Shortly before the 2013 preview, the founder told staff in an internal memo that a group chat system would be hard to sell. What was worth selling, in his framing, was a lower cost of communication, knowledge management that took no effort, and faster decisions — a team confident that any useful information was only a search away.S2
Searchable organisational memory
Search over an accumulating archive was the core of the promise before the first customer arrived. At preview, the founder located the difference from rival chat tools in the value added to archived data.T1
Lower cost of communication
One place for a team's conversations, in channels the whole team could read.
Less internal email
Slack positioned itself as a gradual replacement for internal email. The press shorthand of an email killer overstated the company's own claim.
Persistent shared knowledge
What a team said and decided stayed where a later joiner could find it.
Integrations
Connections to other tools — documents, code, support, deploys — were present from the preview and were the second differentiator.T1
Retrievability
The first customers were small teams adopting on their own authority. What they bought was being able to find things again.
Message history was not incidental to Slack. It was central to the product proposition from the beginning.
That is why this investigation gives later changes to history, retention and search access more evidentiary weight than changes to other features.03The original bargain
Free to use, with the archive behind the paywall — and nothing deleted.
The freemium line at launch was drawn on archive depth. A team's own accumulating history was the asset that payment unlocked, from the first day.
Free use, with a visibility limit
Free teams could see and search only their most recent 10,000 messages. There was no charge and no limit on the number of users.T2T24
Older history hidden, not deleted
Messages beyond the limit were kept. The limit governed what was made available, not what existed. Upgrading restored access to the full archive.T2
Slack monetised access to accumulated history from the beginning. Read neutrally, that is a usage-proportional paywall that leaves light users free indefinitely. Read critically, it is a lever that grows with the customer's dependence. Both readings fit the same facts. Slack did not suddenly begin monetising history in 2022 or 2024; the later change was narrower and is set out below.
Fair Billing: charging for the people actually using the product.
Slack became known for billing eligible self-serve customers on active use and automatically crediting seats that go inactive. The practice is confirmed in the company's 2019 listing document.S1 Its scope should not be overstated: the benefit has always been account credit and not a cash refund, it was a help-centre policy before it was named in the customer terms from late 2016, and it applies to self-serve purchases, not to sales-negotiated contracts.S704The long stable bargain
Eight and a half years in which the public bargain barely moved.
Slack's public list prices and its fundamental free-plan boundary stayed where they were from launch until 1 September 2022. Slack's own announcement described the 2022 change as its first price increase since 2014.S3
The starting terms
Standard: approximately $8 monthly / $6.67 annual, per user.
Free: latest 10,000 messages visible; older history retained.
Same price architecture, growing product
The basic public price architecture remained unchanged for approximately 8.5 years while threads, Enterprise Grid, Workflow Builder and Slack Connect were added.
The qualification: these are list prices. Enterprise pricing is private.
The first eight-plus years do not support a narrative of relentless extraction.
Slack expanded functionality, and customers' dependence on it, while largely preserving its basic public pricing and free-history bargain. That stability is what makes the later changes meaningful.05Salesforce
Slack Became Something Much Larger
Salesforce announced the acquisition in December 2020 and completed it in July 2021, at a transaction value of approximately $27.7 billion.T5S18 The stated rationale was integration from the first day.
Clips
Recorded audio and video messages; extended to the free plan in 2022.
Customer utilityRebuilt Workflow Builder
A new automation platform with connectors to outside systems.S19
Utility and footprintSlack AI
Search answers, summaries and recaps, first sold as a paid add-on.S21
Utility and footprintEnterprise Search
Search across connected outside systems; top tier only.S25
Utility and footprintSalesforce channels
Customer records in channels; on every plan from June 2025.S5
Utility and footprintAgentforce
Salesforce agents in Slack; separately licensed and tied to a Salesforce organisation.S22
Utility and footprintRebuilt Slackbot
A personal work agent, generally available on Business+ and Enterprise+ at its January 2026 launch.S23
Utility and footprintSalesforce materially expanded Slack's capabilities. That finding is strongly supported.
These additions were not all purely for customers' benefit, and not all purely monetisation. Several deliver clear user value while also carrying Salesforce data into Slack or sitting in the upper tiers. The finding rests on what shipped; spending on Slack is not disclosed.06The free plan
Hidden Became Deleted
This is one of the strongest findings on the page, and it needs precise wording. The significant transition is recoverable history becoming irreversible deletion — not the arrival of a paywall on history, which had been there since 2014.
The state of a free workspace's history today
Messages and files can be viewed and searched.
Retained but not shown. Upgrading to a paid plan makes this band available again — and only this band.
Removed on a rolling basis. It cannot be restored, by upgrading or otherwise.S4
What makes it consequential
Before 26 August 2024 there was no deleted state for free workspaces. The 2022 change altered what could be seen; the 2024 change altered what exists, and it reaches paid workspaces that downgrade. The 2022 change was itself a trade-off: Slack said most active free teams gained visible history, while low-volume, long-lived communities lost their long tail, with no grandfathering.S3
What mitigates it
Roughly two months' notice was given, with email reminders before the deadline. No payment had been taken for the affected data, and an export route remained, though a standard free export is limited.T7T8S10 Slack's stated reasons concerned service quality and a reduced storage offering. Clips and retention settings moved into Free in 2022. Motive is not established.
On wording. Slack did not start charging for history in 2022 or 2024: access to accumulated history was part of the paid proposition at launch. The precise finding is that hidden, recoverable history later became permanently deleted history.
07AI and packaging
AI Went From Add-On to Plan Architecture
In a little over a year, generative AI in Slack moved from something a customer could decline to buy into the definition of the plans themselves.
2024 · optional add-on
≈$10Slack AI launches as a paid add-on, reported at approximately $10 per user per month on Pro and Business+.T9
It covered AI search answers, summaries and recaps.
June 2025 · restructure
4 tiersAI capabilities are redistributed across the plans. A new Enterprise+ tier is created.
The separate add-on is withdrawn from sale.S6
Business+ · the price
≈20%Business+ rises from approximately $12.50 to $15 per user per month on an annual-billing basis, with the broader AI set included.S5
| Plan | AI included | List price |
|---|---|---|
| Pro | Conversation and thread summaries; huddle notes | Unchanged |
| Business+ | Broader AI and search: search answers, recaps, translations, file summaries, workflow generation | Up approximately 20%T10 |
| Enterprise+ | Higher-order functions such as enterprise search | Not public |
| Slack AI add-on | Previously purchasable on Pro and Business+ | Withdrawn from sale |
This table records the June 2025 announcement. Slack has since revised what each plan includes; the current split is on Slack’s pricing page.S9
What supports a yield reading
Bundling applied to an installed base.
- No non-AI option at the tier.A Business+ customer that had not bought AI pays about 20% more and receives AI it did not choose.
- Fuller AI moved up-tier for Pro.At the June 2025 restructure, Pro customers who had bought the add-on had to move to Business+ to keep search answers and recaps.
- Applied at renewal.Existing self-serve customers moved at their first renewal after mid-August 2025.
What the same change gave customers
Reported together, as the evidence requires.
- Pro's price did not change.Pro gained AI summaries and huddle notes at the existing price.
- Prior add-on buyers pay less.Business+ with the add-on had cost about $22.50 in total; the bundled plan is about $15.
- Security moved down-tier.Session controls, device blocking and mobile download restrictions were extended to Free and Pro.
Value expansion and monetisation occurred together. This is the clearest feature-level example of the wider Slack finding. Microsoft and Google also folded AI into their base plans in the same period.
08Pricing counterweight
Slack Got More Expensive — and Cheaper
A page that listed only the increases would mislead. On public list prices, Slack's long-run record is one of restraint.
How to read the real-terms figure. It is this investigation's arithmetic on public Pro list prices and the US consumer price index from February 2014 to August 2026, and should be treated as approximate. It does not mean every customer pays less: enterprise pricing is private, and a Business+ customer's position changed in 2025. What it shows is that public Pro pricing does not support a thesis of aggressive long-run price extraction.S9T20
Fair Billing
The policy still exists for eligible self-serve plans. Seats inactive for more than 28 days are detected automatically and credited.S7
Self-service cancellation
A workspace owner can downgrade or cancel in the billing settings without contacting sales.S8
Features that moved down
Clips and retention settings to Free in 2022; AI summaries into Pro and several security controls to Free and Pro in 2025.S6
Metered workflow pricing
Usage-based charges for premium workflows were introduced in September 2023 and withdrawn a year later.S19S11
Credits, not refunds
Fair Billing has always returned account credit, not cash, and it covers self-serve purchases only.
Contracts work differently
Sales-negotiated customers buy fixed quantities for a term; their pricing is not observable.
09The developer and data ecosystem
From Integration Layer to Managed Gateway
Integrations were foundational to Slack's original product. Over time, access has been governed increasingly through Marketplace requirements, developer policies, API terms, rate limits and data-use restrictions. The changes of 2024–2025 are the ones that reach customers.
An open platform. A public app directory and a fund for third-party builders; outside clients could connect through open chat protocols.
More openProtocol gateways closed. Slack said the older protocols could not carry newer features such as threads and shared channels. All client access moved to Slack's own clients and APIs.T19
Less openMarketplace becomes the commercial channel. The developer policy directs apps intended for commercial distribution at scale to Slack Marketplace review and prohibits using Slack data to train large language models.S13
Channel controlData-use terms and rate limits. The API terms changed on 29 May 2025; the current version, effective October 2025, bars third-party commercial apps from bulk-exporting Slack data, from keeping persistent copies or indexes of other organisations' data, and from using it to train language models. From the same date, new installations of commercial apps distributed outside the Marketplace are sharply rate-limited on conversation-history methods.S14T11S15
Data accessWhy this matters to customers, not only to developers
A customer may choose an outside tool that wants to build a persistent, searchable index of that customer's Slack data. The newer rules restrict that architecture: the vendor must query Slack at the moment of each request instead. One enterprise-search vendor was reported to have told customers that Slack data could no longer be added to its index.T12 Over the same period, Slack and Salesforce have increasingly sold their own AI search, enterprise search, retrieval and agents. The customer can still export its data; what has narrowed is the choice of who may hold a working copy.
What tightened
Each point rests on Slack's published policy or terms.
- Bulk export by third parties.Barred unless expressly allowed by a separate agreement.
- Persistent third-party indexing.Outside providers may not keep long-term copies, archives or indexes of other organisations' Slack data.
- Language-model training and use.Training models on Slack data is prohibited.
- History APIs for unlisted apps.New installations of commercial apps outside the Marketplace are throttled on conversation history.
The counterarguments, which are legitimate
None is displaced by the evidence.
- Security.Slack cites the risk of large-scale exfiltration of sensitive conversation data through these methods.S14S16
- Governance and privacy.Query-time access respects each user's current permissions; a stored copy may not.
- Infrastructure.Bulk history crawling carries a real cost and load.
- A controlled partner architecture, applied both ways.Rival AI vendors are admitted on the new route, and Slack's own enterprise search queries outside systems without indexing them.S25
Finding: ecosystem control increased. The security rationale and the competitive effect both fit the evidence and are not mutually exclusive. Motive is inconclusive: no internal document was found for the decision, and this page does not convert timing into intent or claim that any competitor was deliberately targeted.
10Lock-in and dependency
Slack Became Harder to Replace Mostly Because It Became More Useful
What a customer would have to leave behind has accumulated layer by layer. Most of it is ordinary: the product does more work, so more work depends on it.
- Message history
- Files
- Integrations
- Workflows
- Identity and security
- Compliance
- Slack Connect
- Canvas
- Lists
- Enterprise search
- Salesforce data
- AI context
- Agents
Users stay because the product performs useful work.
The evidence supports substantial product dependency. Workflows, inter-company channels and compliance configuration cannot be recreated elsewhere by an export. A rival's migration tool moves channel content but not workflows, custom apps or shared channels — largely an inherent difference between products.T18
Salesforce integration adds to it by mechanism, though no churn or migration data exists to measure the effect.
Users stay because exit has been deliberately obstructed.
The evidence does not establish that Slack's switching model is primarily artificial obstruction. Cancellation remains self-service, and customers keep their own export routes.S8S10
The friction that does exist is specific: export of private channels and direct messages is gated by plan and application, standard exports carry links to files and not the files, and the 2025 API terms limit a customer's choice of outside architecture.
Why CHI separates the two. Ordinary stickiness is not hostility. On this record Slack's dependency is mostly the kind created by usefulness.
11Customer benefit ledger
What customers gained, in order.
Evidence that weakens a negative thesis is kept here by design. Each entry carries its limit.
Free plan with unlimited users. Indefinite free use, with the archive preserved.T24
Limit: latest 10,000 visibleFair Billing. Automatic credits for seats that go inactive.
Limit: credits; self-serveUnchanged list prices. About eight and a half years without a public increase.
Limit: list prices onlyTwo-factor authentication and an app ecosystem. Account security for every plan; a public directory of integrations.
All plansThreads and Enterprise Grid. Organised conversation for all users; company-wide scale, identity and compliance for large organisations.T15T16
Grid: no public priceWorkflow Builder. No-code automation.
Limit: paid plansHuddles and clips. Lightweight audio and recorded messages; clips and retention settings reach the free plan in 2022.
Group huddles paidCanvas and Lists. Documents and task tracking alongside conversation.
Limited or absent on FreeMetered workflow pricing withdrawn. A usage-based charge removed a year after it appeared.
Paid plansAI summaries in Pro at no price change. Conversation and thread summaries and huddle notes.
Fuller AI: Business+Security and admin features moved down. Session controls, device blocking and mobile download restrictions on Free and Pro.
Down-tierAI search and enterprise search. Answers drawn from a workspace's own history; search across connected outside systems without copying their data.
Upper tiers onlyAgent workflows. A rebuilt Slackbot included in Business+ and Enterprise+ at its January 2026 launch; third-party AI agents admitted alongside Salesforce's own.
Value claims vendor-sourcedSelf-service exit and no in-product advertising. The customer pays; there is no advertiser-side incentive to maximise attention.
Structural12Customer cost and control ledger
What customers gave up, and what Slack gained control over.
Only strong findings are listed. This ledger is shorter than the benefit ledger because the evidence is.
Free-history model changed. Access to the latest 10,000 messages became access to the last 90 days, with no grandfathering for long-lived, low-volume workspaces.
10,000 messages → 90 daysFree-plan history became destructible. Content older than one year is permanently deleted on a rolling basis, including in workspaces that downgrade.
Permanent deletion after one yearBusiness+ repackaged. AI bundled into the plan together with a price increase of approximately 20%, with no non-AI option at that tier.
AI bundle + ≈20%Developer and API architecture. Greater Slack control over third-party indexing and retention of customers' Slack data.
Ecosystem controlAlso in the record, and narrower
Export transparency. In April 2018 Slack discontinued the automatic notice members had received when exports of private channels and direct messages were enabled for their workspace; telling members became the employer’s decision. Slack cited GDPR. This was done by independent Slack, before the acquisition; owners must still apply for the export tool.T22T23S10
Pre-SalesforceA default on data use. Customer data is used by default to develop non-generative models such as search ranking and recommendations; opting out requires a workspace owner to email Slack.S17
Not generative AI13What Slack was, what Slack became
The same product name, a different customer relationship.
The comparison is meant to show how the relationship changed, not to argue that early Slack was better.
| Dimension | Early Slack | Slack 2026 |
|---|---|---|
| Core job | Searchable team communication | Communication plus documents, automation, AI and agents |
| Primary customer | Self-selecting teams | Teams, enterprises and Salesforce customers |
| Search | The team archive | Archive plus AI answers and enterprise search |
| Free history | 10,000 messages visible; older history retained | 90 days visible; older than one year deleted |
| Paid value | Archive, integrations, storage | AI, automation, security, compliance, Salesforce features |
| Product breadth | Messaging-centric | Work platform |
| Ecosystem | Integration-heavy and open | Managed Marketplace and API architecture |
| Dependency | Archive and integrations | Workflows, identity, data, AI and Salesforce |
| Monetisation | Freemium software subscription | Tiered subscription, AI and the Salesforce ecosystem |
Much of this movement is what happens when a team tool becomes enterprise infrastructure, and a good deal of it pre-dates the acquisition. What is specific to the Salesforce period is who sets the terms of access to the archive.
14CHI mechanisms SP001–SP004
Four mechanisms tested. Two present, one ordinary, one absent.
CHI tests four defined mechanisms against a company's record. A match means the mechanism is present in the evidence. It is not a hostility verdict and carries no score.
Charging for, restricting or metering valuable access that sat outside the paying entitlement
Supported narrowlyBest evidence: the 2022 free-plan history transition. For a low-volume workspace, older history had been inside the free entitlement; afterwards it required a paid plan.
Qualification: historical access was already monetised from launch. The 2024 deletion restricts access but cannot be bought back, so it fits this mechanism only for the band between 91 days and one year.
Greater yield from existing customers through pricing, packaging, add-ons or upselling
Strongly supported as presentModest on headline list-price escalationEvidence: tier evolution, the Business+ AI bundle, enterprise monetisation through a new top tier, and additional paid capabilities such as separately licensed agents.
Qualification: public Pro pricing is unusually restrained over Slack's full history, and enterprise renewal pricing is unobserved.
Retiring, migrating or deprioritising a legacy product, feature or platform
Supported in ordinary formSlack has retired or replaced legacy calls, older document and bot formats, earlier developer architectures, the original workflow tool and several features and plans.S12
Not exceptional: most retirements came with a replacement and long notice.
An explicit link between external cost pressure and a customer-economic action
Not supportedNo Slack or Salesforce statement links a price or entitlement change to an external cost. AI inference cost is a plausible unstated driver of the 2025 bundle, but this page does not convert inference into fact.
15Falsification
What the Evidence Did Not Support
An adversarial research stream was tasked with overturning the strongest negative readings. These popular claims did not survive in the form usually stated.
Slack states that customer data is not used to train generative models without opt-in consent. What is established is default use for non-generative models, with an email-only opt-out, which Slack's published principles did not clearly distinguish from generative AI until May 2024.S17
One increase of about 9% in twelve years; approximately 23–24% cheaper in real terms than at launch.
The policy is live for self-serve plans and still credits inactive seats.S7
Slack is sold on its own, with a free tier and self-serve plans, and no Salesforce licence is required.S9
The company pivoted; the product was a new build modelled on staff tooling.
The archive paywall dates from 2014, and the 2018 gateway closure and export-notification change were made by independent Slack.
16Method and disposition
- API and data-indexing restrictions
- Permanent free-plan deletion
- A possible weakening of the SLA
Three candidates were evaluated and none exceeded the high threshold. The API finding is significant but fits ordinary ecosystem-control analysis. Free-plan deletion is consequential but is adequately handled within this standard company page. The SLA question remains unresolved and is not a claim made on this page.
Conclusion
Slack's history does not support a simple story of a good independent company corrupted by Salesforce.
Its earliest product already monetised access to accumulated organisational history, while also offering unusually customer-friendly pricing and billing. For most of a decade, that bargain stayed remarkably stable.
Under Salesforce, Slack became dramatically more capable and more deeply embedded in enterprise work — and the customer relationship changed with it. Free history became destructible. AI became part of the tier architecture. The ecosystem became more controlled. Salesforce integration increased both Slack's strategic importance and customers' dependence on it.
The evidence supports neither the claim that Slack turned on its customers nor the claim that nothing meaningful changed. Slack created substantially more value while simultaneously claiming substantially more control over the environment in which that value exists.
Sources and method
How this page was built, and how far it can be relied on.
What was done
Twelve research streams covered Slack's origins, product, pricing, free plan, billing, the acquisition, data and export, the developer platform, AI, reliability and security, and a competitor comparison. One stream was tasked with overturning the strongest negative readings, and its verdicts override earlier conclusions throughout.
Limits
The web archive could not be reached, so no historical page was read as it stood at the time. Source text was retrieved by automated extraction and has not been proof-read by eye, so this page paraphrases and quotes no one. Enterprise contract terms are private. Points the research left unresolved are omitted, not asserted.
Conventions
Prices are US public list prices per user per month and are given as approximate. Real-terms figures are CHI arithmetic on the US consumer price index. Motive is never inferred from timing. No CHI, CVI or CFS score is assigned; a score is reserved for later adjudication under the methodology.
Slack and Salesforce documents
Slack Technologies, Form S-1 registration statement, 2019 — corporate history, billing practices, plans. sec.govPrimary
Stewart Butterfield, internal memo to staff of 31 July 2013, as later published by its author. medium.comCompany statement
Slack blog, pricing and plan updates, 18 July 2022 — first price increase since 2014; 90-day free history. slack.comPrimary
Slack Help, updates to message and file history on free workspaces — deletion of content older than one year from 26 August 2024. slack.com/helpPrimary
Slack blog, June 2025 pricing and packaging announcement, 17 June 2025. slack.comPrimary
Slack Help, updates to feature availability and pricing for Slack plans — AI by tier; add-on withdrawn; security features extended. slack.com/helpPrimary
Slack Help, Fair Billing Policy, retrieved 3 October 2026. slack.com/helpPrimary
Slack Help, change or cancel your paid Slack plan, retrieved 3 October 2026. slack.com/helpPrimary
Slack pricing page, retrieved 3 October 2026 — current plans and list prices. slack.com/pricingPrimary
Slack Help, export your workspace data — export scope by plan. slack.com/helpPrimary
Slack Help, Slack updates and changes — dated feature record, including Lists, workflow billing and Slack CRM. slack.com/helpPrimary
Slack Help, Slack feature and plan retirements. slack.com/helpPrimary
Slack developer changelog, App Developer Policy update, 10 December 2024. docs.slack.devPrimary
Slack developer changelog, rate-limit changes for non-Marketplace apps, 29 May 2025, and the clarification of 3 June 2025. docs.slack.dev · clarificationPrimary
Slack API Terms of Service, version effective October 2025. slack.comPrimary
Slack developer blog, secure data connectivity — Slack's stated rationale for the API changes. slack.devCompany statement
Slack, privacy principles: search, learning and artificial intelligence. slack.com/trustPrimary
Salesforce release, completion of the Slack acquisition, 21 July 2021. salesforce.comPrimary
Slack blog, the new Workflow Builder, 6 September 2023. slack.comPrimary
Slack blog, Slack canvas launch, 25 April 2023. slack.comPrimary
Slack blog, Slack AI general availability, 14 February 2024. slack.comPrimary
Salesforce, Slack announcements at Dreamforce 2024, 16 September 2024 — Agentforce in Slack; Salesforce channels. salesforce.comPrimary
Salesforce release, new Slackbot general availability, 13 January 2026. salesforce.comPrimary
Salesforce, real-time search API and MCP server announcement, 1 October 2025. salesforce.comPrimary
Slack blog, enterprise search, 5 March 2025. slack.comPrimary
Slack blog, what was new in Slack in 2021, 9 December 2021 — huddles, clips, scheduled send. slack.comPrimary
Press and secondary sources
Preview release coverage, TechCrunch, 14 August 2013. techcrunch.comContemporaneous press
Public launch coverage, TechCrunch, 12 February 2014 — free limit of 10,000 messages; nothing deleted. techcrunch.comContemporaneous press
Glitch closure announcement as reported, Boing Boing, 15 November 2012. boingboing.netContemporaneous press
Building Slack, on the end of Glitch and the start of Slack, 20 December 2024. buildingslack.comInsider retrospective
Acquisition announcement coverage, CNBC, 1 December 2020. cnbc.comSecondary
2022 price and free-plan change coverage, The Register, 19 July 2022. theregister.comSecondary
Free-workspace history deletion, as first reported, TidBITS, 24 June 2024. tidbits.comSecondary
Reminder emails before the deletion deadline, Forbes, 19 August 2024. forbes.comSecondary
Slack AI add-on pricing, Computerworld, April 2024. computerworld.comSecondary
2025 AI features and revised pricing, No Jitter, 17 July 2025. nojitter.comSecondary
API terms change coverage, Computerworld, June 2025. computerworld.comSecondary
Report of an enterprise-search vendor's notice to customers, Salesforce Ben, 11 June 2025. salesforceben.comTrade press; notice not seen directly
Slack executive on the API changes and partner reaction, TechTarget, 23 July 2025. techtarget.comTrade press
Real-time search API and MCP server general availability, Reworked, February 2026. reworked.coTrade press
Threads launch, TechCrunch, 18 January 2017. techcrunch.comContemporaneous press
Enterprise Grid launch, TechCrunch, 31 January 2017. techcrunch.comContemporaneous press
Slack Connect launch, VentureBeat, 24 June 2020. venturebeat.comSecondary
Microsoft Learn, Slack to Teams migration tool — what a rival's migration tool does and does not move. learn.microsoft.comThird-party primary
Closure of the IRC and XMPP gateways, Slashdot, 8 March 2018, reporting Slack's statement. slashdot.orgSecondary
US Bureau of Labor Statistics, consumer price index, Table 1 — index values used for the real-terms calculation. bls.gov (August 2026: 334.980) · bls.gov (February 2014: 234.781)Official statistics
Founder interview on the decision to build a second product, Masters of Scale. mastersofscale.comFounder retrospective
Announcement of the 2018 export changes, Fast Company, 21 March 2018. fastcompany.comContemporaneous press
Discontinuation of automatic member notices for exports, NBC News, 2018. nbcnews.comContemporaneous press
Slack pricing page as archived, 12 February 2014 (launch day) and 6 October 2014 — free use with no limit on users, a 10,000-message searchable archive, Standard at $8 per user monthly and $6.67 on annual billing. web.archive.org (Feb 2014) · web.archive.org (Oct 2014)Archived primary
The complete research dossier, with its evidence ledger, falsification findings and register of points withheld from publication, is preserved by CHI and is not reproduced here. Slack and related marks belong to Slack Technologies and Salesforce; the mark is shown only to identify the company, and no endorsement or affiliation is implied. This page is research, not legal or financial advice.
Reading this beside the rest of the index
Every company here is assessed against the same question. Slack is the one where the value and the control grew together.
Read it alongside the methodology and the other company assessments in Productivity Software.