Search & message history
Search is the feature you use most and the one Slack quietly limits the hardest — 90-day cap on free, mediocre relevance at scale, and AI search now gated behind Business+.
What people actually say
✕Slack's free plan limits search and message visibility to the last 90 days — for older workspaces this effectively erased years of decisions and forced upgrade or migration.
Source: Slack, Free plan feature limitations ↗✕Data imports from Slack into Zulip jumped roughly 40x in the weeks after the 90-day history change — communities and educators called it a deal-breaker.
Source: Zulip blog, Slack free plan exodus ↗✕AI search and daily recaps were re-packaged into Business+ in 2025 — Pro customers who wanted the $10 AI add-on now have to jump to a tier that nearly doubles their per-seat cost.
Source: UserJot, Slack pricing 2026 hidden fees ↗
Messages live in Postgres, indexed in Meilisearch or OpenSearch for sub-100ms typo-tolerant search across every channel, every year. Bolt in a Claude or GPT call against the same index for natural-language queries — your model bill is pennies per question, not a $5-per-seat tier jump.