Comments & Discussions
Let users discuss objects in your product — posts, documents, PRs, designs — with threading, mentions, and moderation.
Options
Threading Model*
Content Features
Moderation Controls
Decision Points
Is this a collaboration tool or a public discussion forum?
If yes
Collaboration: one-level replies. Forum: flat or deep nesting depending on culture.
If no
Flat list is usually enough for product reviews or simple feedback surfaces.
Are comments visible to non-authenticated users or strangers?
If yes
Invest in moderation tooling from day one — flagging, rate limits, and either manual or automated review.
If no
Internal/authenticated discussions need less moderation but still need edit/delete.
Support edit with full edit history?
If yes
Store every edit as a version row — useful for trust and dispute resolution, but plan a UI to expose history without cluttering the main view.
If no
An "edited" marker without history is enough for most collaboration tools.
Hard-delete comments or leave a tombstone on removal?
If yes
Tombstones (show "[deleted]" in-place) preserve thread context — the right call for anything threaded.
If no
Hard delete is fine for flat comment lists where there is no structural reply to preserve.
Moderation timing: pre-publication, post-publication, or none?
If yes
Pre-publication review is required for regulated industries (children, health). Expect significant moderator workload and latency from post to visible.
If no
Post-publication review (flag and hide) is standard — fast for users, with moderator queues for flagged content.
Rich text, Markdown, or plain text only?
If yes
Markdown is the sweet spot — expressive, safe, and ubiquitous. Render server-side with a sanitizer; never allow raw HTML.
If no
Plain text is appropriate for short-form reactions (reviews, microposts) where formatting adds nothing.
Comment permalinks required?
If yes
Every comment needs a stable ID and shareable URL — critical for linking in tickets, emails, and threads.
If no
Skip permalinks for ephemeral surfaces where no one will ever cite a specific comment.
Allow anonymous/guest commenting?
If yes
Require captcha and aggressive rate limits — anonymous comments are the #1 spam vector. Store IP and user-agent for abuse investigation.
If no
Authenticated-only commenting dramatically reduces moderation burden.
Do you need spam/abuse detection (Akismet, Perspective)?
If yes
Akismet for spam, Perspective API for toxicity — both are advisory signals feeding a human review queue, not auto-ban triggers.
If no
Manual flagging + rate limits are enough for low-volume or trusted-user surfaces.
Allow file or image attachments in comments?
If yes
Add object storage and content-type validation; require virus scanning if comments are public. Consider size limits per comment and per user.
If no
Text-only comments dramatically reduce moderation, storage, and security surface.
Full-text search over comments?
If yes
Postgres tsvector covers you up to ~10M comments; switch to Meilisearch/Typesense when search becomes a core workflow.
If no
Users navigate to the parent object and scroll — no search index needed for low-volume surfaces.
Owner-exportable comment archive (for GDPR/DSR)?
If yes
Provide a JSON or CSV export endpoint for comment authors — required for GDPR data portability in EU markets.
If no
Internal-only products without EU users can defer this until a customer specifically asks.
Pin or highlight specific comments?
If yes
A boolean pinned flag per comment plus a UI treatment — useful for FAQs, announcements, or marking resolution on issue threads.
If no
Skip pinning if comments are short-lived conversational — it adds UI and moderation complexity.
Inline translation across languages?
If yes
Call Google Translate or DeepL on-demand per comment and cache translations — full pre-translation wastes API budget.
If no
Skip translation for single-language communities or where users handle translation externally.
Tradeoffs
Mobile UX suffers past 3 levels; pagination and collapse behavior need design attention
Expand notification infrastructure — mention notifications are high-priority and user-visible
Third-party ML dependency and ongoing tuning of thresholds to balance false positive rate
Dependencies
Implementation Examples
Lightweight self-hostable comment widgets — reference for minimal moderation and threading.
Full-featured forum software — reference architecture for deep threading and trust-level moderation.
Google's toxicity classifier — common building block for automated moderation.