m: "The size of the chat should be limited to the screen size (- frame) so it does not go via the whole long form..." The grid layout (1fr 1fr at ≥900px) was stretching the chat column to match the form column's height. With a 20-question form the right side of the page became a 3000px scroll-soup of empty chat space. Two-line fix: - .fb-participant gets `align-items: start` at ≥900px — grid items take their own natural height instead of stretching to the tallest sibling. - .fb-participant__col--chat gets `max-height: calc(100vh - 2rem)` always + `position: sticky; top: 1rem` at ≥900px. Long form scrolls past it; chat stays pinned in the viewport. On mobile (single-column stack) the existing 70vh cap stays — the desktop max-height applies on top of it, so mobile uses min(70vh, 100vh - 2rem) which is just 70vh. No markup changes — pure CSS.
fdbck.msbls.de
Per-link feedback forms and live-chat masks. Anonymous, slug-gated, no auth required for participants.
Spun out from m/flexsiebels.de issue #63 — full design at docs/plans/feedback-feature.md.
Stack
SvelteKit 5 + Svelte 5 + bun + @sveltejs/adapter-node. Postgres + Supabase auth. Schema: fdbck.feedback_{instances,submissions,posts} on supa.flexsiebels.de (msupabase).
Run locally
cp .env.example .env # fill SUPABASE_*
bun install
bun run dev
Test + check
bun run test # rate-limit + public-scope unit tests
bun run check # svelte-check (type errors / a11y)
bun run build # adapter-node production build → ./build
Deploy
Dockerfile uses oven/bun:latest. Dokploy app: fdbck.msbls.de. DNS via Hostinger (handled out of band).
Structure
src/
hooks.server.ts — auth + public-scope policy gate
lib/server/
auth.ts — cookie JWT + Supabase refresh
fdb.ts — Postgres `fdbck` schema accessor
feedback.ts — slug generator + DB helpers + rate-limit constants
public-scope.ts — anonymous-DB-access fail-closed gate
rate-limit.ts — in-memory token bucket
schemas.ts — Zod request validation
supabase.ts — admin + anon client singletons
routes/
+page.svelte — landing
f/[slug]/ — public participant page (form + live chat)
admin/feedback/ — m's admin (list + detail + create)
api/
auth/ — sign-in / sign-out
public/feedback/ — anonymous slug-gated endpoints
admin/feedback/ — owner-scoped admin endpoints
Data model (canonical: design doc §5)
fdbck.feedback_instances— slug, title, description, owner_user_id, form_definition (jsonb), chat_enabled, status (open|closed), closed_atfdbck.feedback_submissions— instance_id, display_name (nullable = anonymous), client_session_id, answers (jsonb), client_ip, user_agentfdbck.feedback_posts— instance_id, display_name, client_session_id, body, hidden (m soft-moderate), client_ip, user_agent
Anti-abuse layers
- 32-char base62 slugs (~190 bits entropy)
- in-memory rate-limit (30 posts / 5 min, 10 submits / 5 min, per IP+slug)
- honeypot field on forms + chat (silently dropped)
- body length caps + closing kill-switch
- noindex meta +
robots.txtDisallow: /
Out of scope (v1)
Drag-drop form-builder · post reactions · realtime/SSE · CAPTCHA · trusted-tier owner sharing · branding/theming · auto-notifications. All have a clean upgrade path on the existing schema.
Issue origin
m/flexsiebels.de#63 — m PWA-voice 2026-05-05: "Im Wesentlichen quasi Microsoft Forms und Teams-Feedback in einem auf einer Webseite."