Demo Reels (Playwright)

Category: Documentation & Demos · Areas: ui, frontend

Description

Areas

ui, frontend

Components

Recording tool: Playwright — headless browser automation with video capture
Output: WebM video files (Playwright native) and/or MP4 (via ffmpeg)
Playback: <video> embed in microsite, or converted to GIF for README
Reproducible capture: Scripted Playwright spec that drives the UI walkthrough
Demo scripts: Playwright test files that exercise the app and narrate visually

Constraints

Demo reels are Playwright specs in tests/e2e/ with a reel prefix or tag — they are both valid E2E tests and visual recordings
Video recording is always-on for reel specs (not just on-failure)
Reel specs run against a seeded database with realistic demo data — the same seed data used for E2E tests
Recordings must be reproducible — re-running the reel spec should produce equivalent output
Do not record manual browser sessions — always use a scripted reel spec
Viewport: 1280x720 (720p) for consistent framing across machines
No audio — the visual flow must be self-explanatory
Pacing: include deliberate pauses (page.waitForTimeout) between actions so the viewer can follow at 1x speed

Demo Reel Requirements

Reel spec conventions

File pattern: tests/e2e/00-reel.spec.ts (numbered to run first, before mutation-heavy tests that might dirty the seed data)
Structured as test.describe blocks, one per section/act
Each test within a describe block is one scene in the reel
Scenes execute sequentially (test.describe.serial) — the reel tells a story with state building across scenes
Include visual narration via injected overlay text or page titles between scenes — the viewer should understand what is being demonstrated

Narrative structure

A demo reel tells a story, parallel to demo-asciinema:

Setup — Show the app’s landing state, dashboard, or login
Navigation — Demonstrate moving between modules/sections
Search — Show finding data via search, filters, or command palette
Editing — Create, update, or delete entities through forms
Verification — Show the result: updated list, success state, changed data
Summary — Return to dashboard or overview showing the final state

What to include in a reel

The app’s primary user journey from start to finish
Real UI interactions that a user would perform (clicks, typing, navigation)
Visible data that proves the app works (populated tables, completed forms)
Transitions between major sections showing the app’s breadth
Loading states and confirmations — the viewer sees what the user sees

What NOT to include

Login flows (pre-authenticate or use seeded session)
Long waits for API responses (seed data should be local/fast)
Error states (unless error handling IS the demo topic)
Browser chrome, DevTools, or console output
Tooltips or hover states that flash too quickly to read at 1x

Playwright Configuration for Reels

// playwright.config.ts — reel-specific settings
const reelConfig = {
  use: {
    video: {
      mode: "on",           // always record for reel specs
      size: { width: 1280, height: 720 },
    },
    viewport: { width: 1280, height: 720 },
    launchOptions: {
      slowMo: 50,           // slight delay between actions for visual flow
    },
  },
};

Or per-spec override in the reel file:

test.use({
  video: { mode: "on", size: { width: 1280, height: 720 } },
});

Video Post-Processing

After the reel spec runs, Playwright writes .webm files to the test output directory (test-results/).

Post-processing steps:

Extract: Copy the .webm from test-results/ to docs/demos/<name>/recordings/
Convert (optional): ffmpeg -i reel.webm -c:v libx264 reel.mp4 for broader browser support
Trim (optional): Cut dead time at start/end with ffmpeg
GIF (optional): ffmpeg -i reel.webm -vf "fps=10,scale=640:-1" reel.gif for README embedding (keep under 5MB)
Copy to microsite: Place in website/static/demos/ for embedding

Microsite Embedding

Use a standard HTML5 video element or a Hugo shortcode:

<video autoplay loop muted playsinline width="100%">
  <source src="/demos/app-reel.mp4" type="video/mp4">
  <source src="/demos/app-reel.webm" type="video/webm">
</video>

Or a Hugo shortcode (create layouts/shortcodes/demo-video.html):

{{< demo-video src="app-reel" >}}

Drift Signals (anti-patterns to reject in review)

Manual screen recording instead of scripted Playwright spec → automate it
Reel spec with video: "off" or video: "retain-on-failure" → must be "on"
Reel spec that depends on external services without seed data → seed locally
Video with browser chrome visible → use headless or fullscreen viewport
Reel with no pauses between actions → add waitForTimeout for pacing
Screenshot-only demo → use video for multi-step workflows

When to use

Any project with a web UI that needs to demonstrate functionality to users, stakeholders, or evaluators. The web equivalent of demo-asciinema — scripted, reproducible, and version-controlled. Composes with e2e-playwright for the testing infrastructure and ux-radix for the interaction patterns being demonstrated.

Artifact Impact

Selecting this concern requires these artifacts to change (a selected concern absent from them is drift):

ADR: Playwright reel specs (video capture, seeded data, fixed viewport) as the demo-reel mechanism

Practices by activity

Agents working in any of these activities inherit the practices below through runtime work context, such as a DDx bead context digest.

Requirements (Frame activity)

Identify which user journeys need demo reels — prioritize the “first impression” experience (dashboard → search → create → verify)
Define the narrative arc: what should the viewer understand after watching?
Determine target audience: evaluators seeing the product for the first time, or users learning a specific workflow?
Ensure seed data exists that makes the demo look realistic (real names, realistic numbers, populated lists)

Design

One reel per major workflow or product area — do not combine unrelated features into one recording
Reel spec lives alongside E2E tests: tests/e2e/00-reel.spec.ts
Numbered 00- prefix so it runs first, before mutation-heavy tests
Sequential scenes within test.describe.serial blocks — each scene builds on the previous state
Narrative structure: Landing → Navigate → Search → Edit → Verify → Summary
Viewport: 1280x720 (720p) — consistent across all recordings
Pacing: 500-1000ms pause between major actions via page.waitForTimeout

Implementation

Reel spec structure

import { test } from "@playwright/test";

test.use({
  video: { mode: "on", size: { width: 1280, height: 720 } },
  viewport: { width: 1280, height: 720 },
});

test.describe.serial("Product Demo Reel", () => {
  test("Act 1: Dashboard overview", async ({ page }) => {
    await page.goto("/");
    await page.waitForTimeout(1000);  // let viewer absorb the layout
    // assert key elements visible
  });

  test("Act 2: Navigate to module", async ({ page }) => {
    await page.goto("/");
    await page.click('[data-testid="nav-finance"]');
    await page.waitForTimeout(500);
  });

  test("Act 3: Search for entity", async ({ page }) => {
    await page.goto("/finance");
    await page.keyboard.press("Meta+k");  // command palette
    await page.waitForTimeout(300);
    await page.fill('[role="combobox"]', "Orbital");
    await page.waitForTimeout(500);
    // select result, navigate
  });

  test("Act 4: Edit entity", async ({ page }) => {
    // create or update via form
    await page.waitForTimeout(500);
  });

  test("Act 5: Verify result", async ({ page }) => {
    // show updated list, success toast, changed data
    await page.waitForTimeout(1000);
  });
});

Seed data requirements

Reel specs run against the same seeded database as E2E tests
Seed data must look realistic: real company names, plausible addresses, varied statuses, enough rows to fill tables without looking empty
Deterministic seeds (fixed UUIDs, ON CONFLICT DO NOTHING) so reels are reproducible
Include multiple entity states (draft, pending, approved, completed) to show workflow progression

Pacing guidelines

Action	Pause after
Page navigation	1000ms
Modal/dialog open	500ms
Form field fill	300ms per field
Button click (submit)	500ms
Search result appear	500ms
Success confirmation	1000ms
Section transition	1500ms

Visual narration

Since there is no audio, the UI itself must tell the story:

Use page titles and breadcrumbs to show location
Ensure visible feedback for every action (toasts, status changes, count updates)
Fill forms with readable demo data (not “test123” — use “Orbital Dynamics Corp”, “Q4 2026 Revenue Accrual”)
If the app has a command palette, show it — it demonstrates power-user capability

Recording

Ensure seed data: bun run seed or bun run demo to populate the database

Run the reel spec with video:

bun run test:e2e -- tests/e2e/00-reel.spec.ts

Extract video: Playwright writes .webm to test-results/

Convert (optional):

ffmpeg -i test-results/.../video.webm -c:v libx264 -crf 23 reel.mp4

Copy to microsite: cp reel.mp4 website/static/demos/
Embed: Use demo-video shortcode or <video> tag
Commit: Both the source recordings and microsite copy

Steps 1-3 are fully autonomous — an agent or CI job can run them without human interaction as long as the app and database are running.

Testing

Reel specs are valid E2E tests — they assert correctness, not just visual appearance
Run reel specs in CI without video (video: "off") as a smoke test
Run with video locally or in a scheduled CI job to regenerate recordings
After UI changes that affect the demo flow, re-record and review

Quality Gates

Reel spec passes (exit 0) — broken demos must not produce recordings
Video file exists and is playable
Video is under 30MB for web embedding (compress further with ffmpeg if needed)
All scenes in the reel exercise real functionality against seeded data
Demo page in microsite loads and plays the video

Maintenance

Re-record after major UI changes, navigation restructuring, or data model changes
Keep seed data aligned with the reel script — if the reel searches for “Orbital Dynamics”, the seed must contain that entity
When the reel drifts from the actual app behavior, treat it as a bug — either the reel or the app needs fixing
Reel specs are executable documentation — they must stay correct