Technology — 193

Stack

Layer	Technology
Server	Node.js + Express
Database	SQLite via `better-sqlite3`
Map rendering	D3.js + TopoJSON (client-side SVG)
Email	Brevo (transactional SMTP API)
Process manager	PM2
Web server / TLS	Nginx + Let’s Encrypt (Certbot)
Hosting	VPS, Ubuntu 24.04 LTS

Database structure

All data is stored in a single SQLite file at data/193.db. The main tables are:

Table	Contents
profiles	One row per user: display name, email, edit key, verified status
profiles_meta	Extended profile data: birth year, month, day
visits	One row per country visit: profile ID, ISO code, status (overnight/transit), is_territory flag
badges	Earned badges per profile. Updated nightly by the batch job.
email_tokens	Short-lived 4-digit verification codes for email confirmation

Key files

File	Purpose
`server.js`	Main Express application — all routes, page rendering, API endpoints
`data/countries.json`	Master list of 193 UN member states with ISO codes, regions, flags
`data/country-stats.json`	Per-country statistics (population, GDP, coastline, etc.) — regenerated nightly
`data/badges.js`	All badge definitions: criteria, emoji, `check()` functions, `supersedesBy` logic
`data/badge-country-lists.json`	Pre-computed country lists per badge — used on the /badges page
`public/map.js`	Client-side map rendering using D3 + TopoJSON
`public/world-units.topojson`	World map geometry (TopoJSON format)
`scripts/fetch-stats.js`	Fetches live data from World Bank API, writes `country-stats.json`
`scripts/generate-badge-lists.js`	Regenerates `badge-country-lists.json` based on current badge definitions and stats
`scripts/compute-badges.js`	Calculates each user’s badges, diffs against DB, sends notification emails

Nightly batch

Every night at 02:00 UTC, three scripts run in sequence:

00:00  SQLite backup         193.db → 193.db.bak
02:00  fetch-stats.js        World Bank API → country-stats.json
02:15  generate-badge-lists  badge definitions → badge-country-lists.json
02:30  compute-badges.js     badge calculation + email notifications

fetch-stats.js

Calls the World Bank API with four indicators in parallel:

SP.POP.TOTL — total population
AG.LND.TOTL.K2 — land area in km²
NY.GDP.MKTP.CD — GDP in USD
NY.GDP.PCAP.CD — GDP per capita in USD

Other data (coastline, languages, UNESCO sites, climate zones, timezones) is maintained as curated static lists in the script and updated manually when needed.

The batch fetches data using mrv=1 (most recent value) from the World Bank, so it always uses the latest available year for each country — typically 1–2 years behind the current year.

compute-badges.js

For each verified profile:

Load all visits from DB
Run all check() functions from badges.js against the visit list and stats
Apply filterSuperseded() — removes lower-tier badges when a higher tier is earned (e.g. Top 10% hides Top 25%)
Diff against what’s already in the badges table
INSERT newly earned badges, DELETE lost badges
Send a notification email if anything changed

TEST_MODE is currently active. All badge emails are sent only to anders@blauenfeldt.dk regardless of the actual profile email. Set TEST_MODE = false in scripts/compute-badges.js to go live.

Badge supersedes logic

Progressive badges define a supersedesBy field listing higher-tier badge IDs that replace them. Examples:

Country count: 10 countries → superseded by 25, 50, 100, 150, 193
Rankings: Top 25% → superseded by Top 10%, Top 5%, Top 1%
Continent hunters: Three Continents → superseded by Five Continents → All Continents

Only the highest achieved tier is stored in the database and shown on the profile.

Map rendering

The world map is rendered client-side as an SVG using D3.js and a TopoJSON world geometry file. Each country feature in the TopoJSON is matched to a visit by ISO 3166-1 alpha-2 code. The map supports three modes:

Profile map — overnight visits shown in teal (#4dd9b8), transit in dark brown (#8a6a20)
Compare map — shared countries in teal, unique to person 1 in orange, unique to person 2 in purple

Email

All transactional emails are sent via the Brevo API. There are four email types:

Trigger	Subject
New profile created	Email verification code
Email verified	Welcome email with map links
/find request	Your 193 travel page link
Nightly batch (badge change)	You have new badges / Badge update

The sender domain 193.dk has DKIM and DMARC configured for reliable delivery.

OG image

Each profile has a dynamic Open Graph image at /:id/og.png, generated server-side using the Canvas API (canvas npm package). The image shows the user’s name, country count, and a row of flag emojis for their visited countries.