01
Campaign homepage
Sticky header with PL/EN switch; the hero artwork swaps with the language. All copy lives in i18next.
Case study · 08 / 09
Side Quest z Dumle
Consumer contest campaign
A bilingual contest site for Dumle: upload a receipt, tell your side quest, win. Fast and fun on the front — serverless, fully coded infrastructure on AWS behind it.
Partner
Dumle · Fazer
Industry
FMCG · Brand campaign
Platform
Landing page + serverless AWS
Our role
Design build, backend & infrastructure
The product
What it does
Shoppers fill in a form, upload a photo of their receipt and describe their “side quest”. Entries land in a Google Sheet for the organiser and the entrant gets a confirmation e-mail — in Polish or English.
Our part
What we built
A React 19 + TypeScript SPA with i18next, a serverless backend on Lambda and API Gateway, uploads direct to private S3, SES e-mails with DKIM, and five Terraform modules with separate state per campaign — shipped by a GitLab pipeline with smoke tests and Slack alerts.
Under the hood
The hard parts
- 01
Receipts straight to S3
The browser uploads to a presigned URL (SigV4, valid 600 s), skipping Lambda entirely; Lambda only signs the URL and then records the entry.
- 02
Rules enforced on the server
Contest date window, 200-character limit, consents that pass only on an explicit true, and duplicate receipt numbers rejected with a 409 pinned to the right field.
- 03
Infrastructure as code
Five Terraform modules, state per campaign, DNS and ACM certificates in two regions, SES DKIM and least-privilege IAM — down to a SES condition on the from-address.
- 04
Consent that means it
Clarity, Sentry Replay and the Meta and TikTok pixels load only after consent; withdrawing it clears their cookies. Decisions are versioned and expire after 12 months.
The outcome
A campaign site with no servers to babysit — and infrastructure that can be cloned for the next campaign from code.
Inside the product
8 screens, explained
Demo data · click any screen to enlarge
02
The whole page
Hero, stores, what a side quest is, four steps, prizes, the entry form and FAQ — one scroll.
03
Entry form
A keyboard-accessible date picker of our own — days outside the contest are blocked. The native date input lost because iOS ignores min and max.
04
How an entry is sent
POST /presign, PUT the file straight to S3, then POST /submit that returns the entry number.
05
Mobile, in both languages
Hamburger menu, the calendar in English and a 409 “duplicate receipt” error from Lambda attached to the exact field.
06
Cookie settings
Categories and a table of every cookie — name, provider, purpose, lifetime. Analytics and marketing scripts load only after consent.
07
Terms generated from Word
Our Python script parses the client’s .docx (numbered lists included) into HTML, headless Chrome renders the PDF, and the document lazy-loads as its own chunk.
08
Architecture on AWS
Drawn from the Terraform code: CloudFront + S3 with OAC, API Gateway, Lambda, receipts bucket, Secrets Manager, Google Sheets, SES with DKIM, six CloudWatch alarms, budget, SNS, Slack and the GitLab pipeline.
Stack
Frontend
- React 19
- TypeScript
- Vite 6
- SCSS
- React Router 7
- i18next
- Sentry
Serverless
- AWS Lambda (Node 20)
- API Gateway
- S3 presigned URLs
- SES v2
- Secrets Manager
- Google Sheets API
Infrastructure
- CloudFront + OAC
- Route 53
- ACM
- CloudWatch
- SNS
- Budgets
- Terraform
Delivery
- GitLab CI/CD
- Playwright
- Slack alerts
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