RETAIL CRM

01Overview

This isn’t a product; it’s an ongoing software service. I work in the same repositories and the same sprints as the company’s own team: business units open their needs as requests, and I clarify the requirement, write the API, the screen and the integration, ship it to production and follow up. Over time my area has grown to cover customer relationships, messaging, store reporting and e-invoicing.

Need

Customer data comes from the POS, the e-commerce site, the mobile app and marketing tools. Memberships and communication consents have to stay compliant with KVKK, Turkey’s data protection law, and with the Message Management System (IYS), and every message has to reach the right person through the right channel; stores and finance teams also need accurate reports to base their daily decisions on. The requests never stop, and most of them touch more than one system.

My contribution

I developed the CRM’s loyalty, segment and coupon rules, OTP and email verification, and the IYS and customer data platform syncs; I’m currently rebuilding the SMS infrastructure. For the store and finance teams I wrote reporting screens, the ETBIS category mapping and the approval flow for incoming e-invoices. I built from scratch the integration portal that takes sales from the POS and turns them into e-invoices and e-archive invoices, and I moved the applications to single sign-on with Keycloak.

02The life of a request

01
Request
The business unit opens its need in Jira; priority is set together with the team.
02
Analysis
Which system holds the data, which rule applies, what gets affected: all of it is pinned down.
03
Development
An API, a screen, a scheduled job or an integration; often all of them at once.
04
Testing
Verified together with the business unit in the development environment.
05
Release
Goes through code review and ships to production through the deployment pipeline.
06
Follow-up
Logs and scheduled jobs are monitored; feedback drives improvements.

03Highlights

01Loyalty and segmentsGold, Premium and Classic memberships; segment change history, membership anniversary rewards, coupon and point rules. Scheduled jobs run the rules automatically every day.
02Messaging infrastructureCampaign, informational and OTP SMS; order and invoice notifications; audiences targeted by store, category and segment. Verification and welcome emails are generated from templates.
03Consents and KVKKMembership, privacy notice and commercial messaging consents are synced with IYS. The customer data platform sync, the error queue and account deletion requests are tracked end to end.
04Security and single sign-onSingle sign-on and service-to-service client authorization with Keycloak; a suspicious customer list, plus rate limiting and a blocklist for phone lookups.
05Store and finance reportsLine void, payment type, receipt detail and return voucher reports; ETBIS category mapping; a two-step approval flow for incoming e-invoices.
06E-invoice integration portalA portal that turns POS sales into UBL-TR e-invoices and e-archive invoices, talks to the integrator over SOAP, and tracks Revenue Administration (GIB) statuses and errors. I wrote its backend and its React frontend from start to finish.

04E-invoice integration portal

**Invoices**Filter by number, customer, status, source and date; export to CSV and Excel; process and send right from the row.

**Invoice detail**UBL XML, integrator output, HTML preview and PDF; financial details, timeline and GIB status.

**Invoice processing**Sales from the POS are collected source by source and turned into invoices in bulk or one at a time.

**Scheduled jobs**Data collection, submission, status check and retry jobs; a cron editor and run statistics.

**Error management**Severity levels, diagnostic suggestions, retries and a resolution log.

**Reports**Daily summary, period statistics, performance and error analysis; export in four formats.

Screens from the portal I wrote end to end. All screenshots use entirely fictional data; the brand name and logo are hidden.

On the customer’s phone

The membership flow that opens from a QR code in the store. The brand name and logo are hidden in the screenshots.

01Look up by phoneThe customer looks up their record by phone number.

02Membership formSign-up with name, email, phone and date of birth.

03ConsentsPrivacy notices and messaging consents are approved one by one.

05Who uses it

01

Stores

New members at the register, OTP verification, coupon and return processes; store reports.

02

CRM and marketing

Segments, campaign SMS, coupons and consent management.

03

Finance and accounting

E-invoices, e-archive invoices, incoming invoice approval and payment reports.

04

Customers

Sign-up via QR code, tourist registration, email verification and consent approvals.

06Architecture

01Channels

CRM screensCustomers, loyalty, campaigns
Customer formsSign-up, consent, invoice viewing
POS screensIn-store sign-up and returns
Store screensReports, incoming e-invoice approval
E-invoice portalSingle sign-on with Keycloak

02Services

CRM APIRabbitMQ queues · Quartz jobs
API gatewayPublic endpoints and partners
Store APIReport queue · Excel exports
E-invoice integrationFrom sale to e-Invoice and e-Archive

03Data and external systems

Short link serviceInvoice links in SMS
MySQLCRM data · read-only pool
Messaging and consent servicesSMS, email, IYS, CDP
BigQueryCampaign audiences and reports
POS and ERP systemsSales, cards and points · SOAP
E-invoice providere-Invoice, e-Archive, PDF

Customer, loyalty and messaging work lives in the CRM API; campaign SMS, consent checks and syncs run in the background through queues, and scheduled jobs run on Quartz, managed from the database. Forms and partners come in only through the gateway’s public endpoints. The e-invoice integration reads POS sales and sends them as e-Invoices or e-Archive invoices; customers open their invoice from the short link in the SMS.

External service