// 02 — Disciplines

Three disciplines,
one thing only.

// web · backend · mobile

// 02 · 01 i Web · Product

Web,

Full user-facing products. Marketing sites with narrative, dense dashboards, internal panels, e-commerce. Modern rendering: SSR, streaming, edge.

Stack Next · ts · tailwind

LCP target 1.4s p75

Avg lead 6 wks

A11y AA · WCAG 2.2

Next.jsReactTypeScriptTailwindVercelCloudflare

~/proyecto · pnpm build

buildlogsgit

→pnpm build

▲ Next.js 15.2.0 · turbo

- Compiled ✓ in 8.4s (842 modules)

- Type checking ✓ tsc --noEmit

- Linting ✓ 0 errors · 0 warnings

RouteSizeFirst Load

○/2.1 kB112 kB

●/dashboard14.8 kB148 kB

●/dashboard/[org]9.2 kB142 kB

λ/api/webhooks/stripe0 B88 kB

○/(marketing)/[…slug]3.4 kB118 kB

✓build completed12.8s · 0 errors

→

main node 22.4 · ts 5.6 build ok 12.8s

apps/web/app/(dashboard)/orders/page.tsx

treetsxdiff

app /

(dashboard)

orders

page.tsx

layout.tsx

loading.tsx

customers

api

components

middleware.ts

tailwind.config.ts

1import { Suspense } from "react";

2import { getOrders } from "@/lib/orders";

3import OrdersTable from "./table";

5type Props = { params: { org: string } };

7export default async function Page({ params }: Props) {

8 const orders = await getOrders(params.org);

9 return (

10 <Suspense fallback={<Skeleton/>}>

11 <OrdersTable data={orders}/>

12 </Suspense>

13 );

14}

feat/orders tsx · utf-8 · ln 14 prettier no errors

~/proyecto · pnpm e2e

unite2ecov

→playwright test --reporter=line

Running 28 tests using 4 workers · chromium · webkit · firefox

✓auth › login with valid credentials1.2s

✓auth › magic link flow2.4s

✓checkout › cart → payment → receipt4.8s

✓orders › create + cancel3.1s

✓dashboard › renders empty states0.9s

⚠webhooks › retries on 5xx2.6s · flaky 1/3

✓a11y › axe scan home + dashboard3.4s

✓i18n › ES ↔ EN switch persists0.7s

28 passed·1 flaky42.1s

html report → playwright-report/index.html

→

ci playwright 1.48 28/28 42.1s

vercel deploy · --prod

previewprod

✓Cloning github.com/rem-lat/proyecto2.1s

✓Restored cache · 412 MB3.8s

✓Installing dependencies · pnpm14.2s

✓Running "build" · next build38.4s

✓Generating static pages · 24/245.2s

✓Uploading edge functions · 61.9s

●Assigning domain proyecto.com78%

✓deployedhttps://proyecto.com

edge: gru1, mia1, scl1 · cold-start 38ms · ttfb 112ms

→

main vercel · iad1 live 1m 9s

01 / 04 · build

// 02 · 02 ii Backend · Systems

Backend,

APIs, internal systems, integrations. Postgres taken seriously, GraphQL where it fits, events when justified. Spring Boot or Node, case by case.

Runtime Node · postgres

p99 target 200ms

Uptime SLO 99.9%

Coverage ≥80% int.

Spring BootNodePostgresGraphQLAWS

~/api · ./gradlew bootRun

appdbcache

→./gradlew :api:bootRun

. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \\ \\ \\ \\
( ( )\\___ | '_ | '_| | '_ \\/ _` | \\ \\ \\ \\
\\\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\\__, | / / / /
=========|_|==============|___/=/_/_/_/

:: Spring Boot :: (v3.4.1)

15:42:01 INFO [main] c.r.api.Application

Starting Application v0.4.2 on prod-01 with PID 8124

The following 3 profiles are active: prod, postgres, redis

15:42:02 INFO [main] o.s.b.w.embedded.tomcat

Tomcat initialized with port 8080 (http)

15:42:03 INFO [main] com.zaxxer.hikari.HikariDataSource

HikariPool-1 - Starting... → ready

15:42:04 INFO [main] o.s.d.r.c.RepositoryConfig

Bootstrapping JPA 14 repositories · Liquibase up-to-date

15:42:04 INFO [main] c.r.api.Application

Started Application in 3.182 seconds (process running for 3.5)

✓Listening on http://0.0.0.0:8080actuator · /actuator/health

→

main java 21 · spring 3.4 UP 3.18s

api/src/main/java/co/rem/orders/OrderController.java

treejavatests

co.rem /

orders

OrderController.java

OrderService.java

OrderRepo.java

Order.java

users

billing

webhooks

config

Application.java

1package co.rem.orders;

3@RestController

4@RequestMapping("/v2/orders")

5@RequiredArgsConstructor

6public class OrderController {

7 private final OrderService service;

9 @GetMapping("/{id}")

10 public OrderDto findById(@PathVariable UUID id) {

11 return service.findById(id);

12 }

14 @PostMapping

15 @ResponseStatus(HttpStatus.CREATED)

16 public OrderDto create(@Valid @RequestBody CreateOrder cmd) {

17 return service.create(cmd);

18 }

feat/orders-api java · utf-8 spotless compiles

~/etl · pytest -q

testscovlint

→uv run pytest --cov=src -q

platform linux · Python 3.12.4 · pytest-8.3 · plugins: cov-5.0, asyncio-0.23

collected 142 items / 14 modules

✓tests/test_etl_pipeline.py28 passed · 0.9s

✓tests/test_transforms.py34 passed · 1.4s

✓tests/test_models_pydantic.py22 passed · 0.3s

✓tests/test_fastapi_routes.py31 passed · 2.1s

✓tests/test_redis_cache.py16 passed · 0.6s

✓tests/test_workers_celery.py11 passed · 1.2s

NameStmtsMissCover

src/etl/pipeline.py214896%

src/api/routes.py1821293%

src/workers/jobs.py96694%

142 passedtotal cov 94.8% · 6.5s

→

main python 3.12 · uv 142/142 cov 94.8%

psql · prod_replica@db.proyecto.com

schemaqueryplan

prod=> SELECT o.id, u.email, sum(i.price_cents) AS total

FROM orders o

JOIN users u ON u.id = o.user_id

JOIN items i ON i.order_id = o.id

WHERE o.paid_at > now() - '7 days'

GROUP BY 1, 2 ORDER BY total DESC LIMIT 5;

id | email | total

--------------------------------------+---------------------+--------

8a2f04e1-b6c2-4d51-9a3f-c8e1d2f04a91 | m.solis@… | 42180

3c9f2811-a4e1-49c2-b3a8-d1e7c4f50882 | andres@… | 38940

7f12e498-c5d8-4f31-8b6d-2a4e9f0c1b53 | l.paredes@… | 31420

b2e84a30-7f1c-4bd9-94a2-e8f3d6c47a91 | felipe@… | 28760

9d4f1a82-3b6e-4c7f-8a91-c2d5e8f4b073 | camila@… | 24310

(5 rows)

Time: 14.2 ms · planning 2.1 · execution 12.1 · index orders_paid_at_idx

→

prod-replica postgres 16.3 5 rows 14.2ms

01 / 04 · bootRun

// 02 · 03 iii Mobile · Apps

Mobile,

iOS / Android apps when the use case earns it. Native when performance leads; React Native / Expo when iteration speed wins.

Stack Expo · rn · swift

Targets iOS · android

Crash-free 99.7%

Cold start ≤2s

iOSAndroidReact NativeExpo

~/wallet · npx expo start

metroiosandroid

→npx expo start --dev-client

Starting Metro Bundler · sdk 52 · rn 0.76

[15:42:03] › Logs for your project will appear below.

▄▄▄▄▄▄▄ ▄ ▄ ▄▄▄ ▄▄▄▄▄▄▄
█ ███ █ ▄▄▀█▄ ▀█ █ ███ █
█ ▀▀▀ █ ▀█▄ █▀▀█ █ ▀▀▀ █
▀▀▀▀▀▀▀ █ █ █ █ █ ▀▀▀▀▀▀▀
▄▀▀▄▀▀▀ █▄▀▄▀ ▀▄▀▄▀▄▀▄▀▄

› Press i for iOS · a for Android · r to reload

› Metro waiting on exp://192.168.1.42:8081

✓Bundling index.js · iOS1842 modules · 2.4s

✓Bundling index.js · Android1842 modules · 3.1s

15:42:18 LOG [App] mounted · session=usr_8a2f

15:42:19 LOG [Wallet] balance synced · 12481.20 GTQ

15:42:21 WARN VirtualizedList: large list, key=tx-list

15:42:24 LOG [Nav] Home → Send

→

main expo 52 · rn 0.76 connected · iPhone 15 Pro

Wallet/Sources/Views/BalanceCard.swift

treeswiftpreview

Wallet /

Sources

Views

BalanceCard.swift

QuickActions.swift

TxRow.swift

Models

Network

Tests

WalletApp.swift

Package.swift

1import SwiftUI

3struct BalanceCard: View {

4 let balance: Decimal

5 let delta: Decimal

7 var body: some View {

8 VStack(alignment: .leading, spacing: 6) {

9 Text("BALANCE · GTQ")

10 .font(.caption2.monospaced())

11 .foregroundStyle(.white.opacity(0.7))

12 Text(balance, format: .currency(code: "GTQ"))

13 .font(.system(size: 28, weight: .semibold))

14 DeltaPill(value: delta)

15 }

16 .padding(14)

17 .background(LinearGradient(...))

18 .clipShape(.rect(cornerRadius: 14))

feat/balance-card swift 6.0 · ios 17 build succeeded

~/wallet-android · ./gradlew assembleRelease

treebuildlogs

→./gradlew :app:assembleRelease --scan

Configure project · 4 modules · target sdk 34

✓:app:processReleaseGoogleServices0.4s

✓:app:compileReleaseKotlin8.2s

✓:app:lintRelease2.1s · 0 issues

✓:app:bundleReleaseClasses1.8s

✓:app:minifyReleaseWithR812.4s · removed 38%

✓:app:packageRelease3.6s

✓:app:bundleRelease2.2s

BUILD SUCCESSFULin 32s

app-release.aab · 14.8 MB · signed v3 · ready for Play

→ app/build/outputs/bundle/release/

124 actionable tasks: 112 executed, 12 from cache

→fastlane supply --aab app-release.aab

release/0.4.2 kotlin 2.0 · agp 8.5 14.8 MB → Play

~/wallet-flutter · flutter test --coverage

testscovanalyze

→flutter test --coverage --reporter expanded

Flutter 3.24.0 · dart 3.5 · resolving deps... ok

15:42:01 PASS test/widgets/balance_card_test.dart

✓ renders amount with GTQ symbol 0.4s

✓ shows positive delta in green 0.3s

✓ truncates at 9 digits 0.2s

15:42:02 PASS test/widgets/quick_actions_test.dart

✓ taps Send and pushes route 0.5s

✓ disables when offline 0.3s

15:42:03 PASS test/integration/checkout_flow_test.dart

✓ cart → confirm → receipt 2.4s

✓ retries on 5xx with backoff 1.8s

15:42:04 PASS test/golden/onboarding_test.dart

✓ matches golden image (light + dark) 0.9s

All tests passed!87/87 · 7.8s · cov 91.2%

→

main flutter 3.24 · dart 3.5 87/87 cov 91.2%

01 / 04 · metro

Software,
to the point .

Three disciplines,
one thing only.

Web,

Backend,

Mobile,

What we measure.

Each business,
its own language.

Home rentals.

Photographers.

Restaurants.

Clinics & health.

E-commerce.

Professional services.

Digital invitations.

What we always ship, whatever the vertical.

How we work.

Small.

Honest.

Durable.

Starting
is the hard part.

Software, to the point .

Web,

Backend,

Mobile,

Home rentals.

Photographers.

Restaurants.

Clinics & health.

E-commerce.

Professional services.

Digital invitations.

What we always ship, whatever the vertical.

Small.

Honest.

Durable.

Startingis the hard part.

Software,
to the point .

Starting
is the hard part.