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Sheet 01 / 04 · General arrangement

Yohannes Merga

Backend engineer · Python & GoPython · Go · PostgreSQL · RabbitMQ · AWS · Terraform

Drawn by
Y. Merga
Revision
v2.0 · 2026-09
Scale
4 yrs : 1 page
Status
Open to backend roles

I build backend systems in Python and Go, keep TypeScript for the product edge, and draw the diagram before I write the code, so the next engineer knows why it looks like this.

Four years across a real-money poker platform, an AI recruitment platform, a multi-tenant ERP and a bank's internal tooling. Python for services: FastAPI and Django APIs, Kafka and Celery workers, a GPT-4 extraction pipeline. Go for the tooling that keeps production honest: a Terraform provisioning CLI, a MySQL-to-ClickHouse cold-data pipeline and an open-source AWS Encryption SDK wrapper backed by HashiCorp Vault. I own the systems I ship, from schema and queue design to the dashboards that page me.

Experience
4 years, 6 teams, 3 countries remote
Payments
$100k per month, ~1,000 tx/day, KYC/AML
Stability
0 DB errors in the last 3 months
Observability
20+ services on self-hosted ClickHouse
Team
4 engineers led, 10+ mentored
Remote for
USA · Kuwait · Slovenia
FIG. 1

AI-powered ATS, service arrangement

Mereb Technologies · Nov 2024 – Jun 2025
FIG. 1: AI-powered ATS, service arrangementRequest path solid, background pipeline dashed. Express fronts the platform, FastAPI services and Python workers carry ingestion and the GPT-4 pipeline, and Redis brokers every async hop.CLIENT / EDGESERVICES · AWS ECSSTATERecruiter consoleReact 18 · TanStackCandidate portalNext.js · ZustandCloudFront + S3static assetsAPI gateway / BFFExpress.js · auth · rate limit · OpenAPI 3nodecandidatesingestion · profileasync SQLAlchemypyrecruitingjobs · pipelinesscoring rulespyAI pipeline workersGPT-4 · parse, summarize, extract · ~250/daystructured rows → Postgres · retry + reviewpysandbox schedulerDocker Swarm · prebuilt image per challengeRedis · broker · cache · locks · idempotencyPostgreSQLnormalized coreindexes · migrationsTypesensecandidate + job searchresync from PostgresS3 · raw CVspresigned uploadSandbox host~10 isolated IDEs64 GB · role-based accesscheating detection[1] query patterns andindexes tuned for load[2] search kept besidePostgres, not inside it[3] spin-up cut from4 min to 30 ssync requestasync / queued
FIG. 1 · Request path solid, background pipeline dashed. Express fronts the platform, FastAPI services and Python workers carry ingestion and the GPT-4 pipeline, and Redis brokers every async hop.Scroll the drawing sideways to pan.
FIG. 2

Store, payments and Go tooling around a poker core

Real Gaming · Jul 2025 – present
FIG. 2: Store, payments and Go tooling around a poker coreThe store never writes to the poker core directly: gRPC holds the contract. One billing engine drives four payment providers. Go tooling provisions the environment, offloads cold data to ClickHouse and encrypts KYC and payment data with Vault keys.CLIENTSSTORE · SERVICE LAYERTOOLING · GOCORE / EXTERNALGame clientpoker · in-game buysWeb storeNext.jsAdmin toolspolicies · opsrealgaming-store APIExpress · membership · avatars · 24k req/daynodebillingcron → gRPC · scoringcooldowns · capsnodepaymentsidempotent · webhooksreconcile · refundsnodeRabbitMQ · Redis · events, cacheprovisionerTerraform wrapperwhole env up / downgocold pipelineMySQL → ClickHousereporting · WIPgoencryption wrapperAWS Encryption SDK + Vault master key · open sourceKYC docs · PII · payment tokensgopoker coregRPC · 4M req/dayreached via contract onlyphpBraintree · primaryStripe · fallbackHyperwallet · payoutsPlaid · bank transfersMySQL · PostgreSQLpooled · 4 s query capVault · ClickHousesecrets · rotationHyperDX · Slack alerts[1] billing caps vaultedmethods per attempt[2] pool exhaustion fixed:0 errors, last 3 months[3] Datadog replaced:1 → 20+ servicessync requestasync / queued
FIG. 2 · The store never writes to the poker core directly: gRPC holds the contract. One billing engine drives four payment providers. Go tooling provisions the environment, offloads cold data to ClickHouse and encrypts KYC and payment data with Vault keys.Scroll the drawing sideways to pan.
TAB. 1

Measured outcomes

every number, and what it was measured against
DB connection errors
15 → 0
8 months after the pool fix, none in the last 3
Real Gaming, avatar-purchase path
Services observed
1 → 20+
Datadog replaced by self-hosted ClickHouse + HyperDX
Real Gaming, 9 DBs · 4 game servers · Redis · APIs
Daily active users
+17%
150 to 175 in 40 days after launch
Real Gaming, store
Registrations
+55%
9k to 14k in the same 40 days
Real Gaming, store
Payments processed
~$100k / mo
~1,000 transactions/day, 4 providers
Real Gaming, KYC/AML
Recruiter shortlist time
3–4 wk → 1 wk
time to 4 to 5 interview candidates
Mereb, ATS
Candidate pool
<200 → 2,000+
1,000 completed a live challenge in 60 days
Mereb, ATS
Sandbox spin-up
4 min → 30 s
Docker Swarm, prebuilt per-challenge images
Mereb, coding challenges
Search latency
350 → 50 ms
PostgreSQL to Typesense, ~5k documents
Mereb, candidate search
CV extraction accuracy
~90%
~250 CVs/day vs recruiter review
Mereb, GPT-4 pipeline
Backend test coverage
85%
Pytest, CI reports
Sulala
FIG. 3

Build log

reverse chronological · 6 entries
  1. 2025 – presentsince Jul 2025 · remote, Las Vegas USA

    Software Engineer, Backend

    Real Gamingvia Mereb Technologies

    Real-money poker under KYC/AML. I own realgaming-store, the membership and in-game purchase service beside the PHP poker core (24k req/day, gRPC to a core doing 4M/day), and the payment stack behind it: Braintree primary, Stripe fallback, Hyperwallet payouts, Plaid bank transfers. In Go I wrote the tooling around the platform: a Terraform provisioning CLI, a MySQL-to-ClickHouse cold-data pipeline, and an AWS Encryption SDK wrapper with a HashiCorp Vault master key for KYC documents, PII and payment tokens. Replaced Datadog with self-hosted ClickHouse and HyperDX.

    • 0 DB errors in the last 3 months, measured by 15 in 8 months after the pool fix, none since
    • 20+ services observed, measured by up from 1 on Datadog, under 6 h retention
    • +17% daily active users, measured by 150 to 175 in 40 days after the store launch
    • +55% registrations, measured by 9k to 14k in the same 40 days
    • ~$100k/month processed, measured by ~1,000 transactions/day across 4 providers
    • Go
    • Terraform
    • TypeScript / Express
    • gRPC
    • RabbitMQ
    • Braintree
    • Stripe
    • Hyperwallet
    • HashiCorp Vault
    • ClickHouse · HyperDX
    • AWS ECS / Fargate
    • MySQL · PostgreSQL
  2. 2024 – 20258 months · Addis Ababa

    Lead Software Engineer

    Mereb Technologiesled 4 engineers

    Architected an AI-assisted ATS used by 100+ recruiters, 20+ hiring companies and 5,000+ candidates. FastAPI and Express microservices, Python workers for a GPT-4 CV extraction pipeline, Typesense beside PostgreSQL for search, and on-demand isolated coding sandboxes on Docker Swarm with prebuilt per-challenge images. Hired, reviewed and mentored the team.

    • Shortlist in 1 week, not 3 to 4, measured by recruiter time to 4 to 5 interview candidates
    • Pool <200 to 2,000+, measured by 1,000 completed a live challenge in the first 60 days
    • Sandbox spin-up 4 min to 30 s, measured by ~10 concurrent on one 64 GB host
    • Search 350 ms to 50 ms, measured by PostgreSQL to Typesense, ~5k documents
    • ~90% extraction accuracy, measured by ~250 CVs/day, checked against recruiter review
    • Python
    • FastAPI
    • Express
    • OpenAI GPT-4
    • LangChain
    • PostgreSQL
    • Redis
    • Typesense
    • Docker Swarm
    • Next.js
    • GCP · Hetzner
  3. 20244 months · remote, Slovenia

    Backend Developer

    PRO-BIT programska oprema d.o.o.contract

    Multi-tenant ERP (accounting, inventory, CRM, finance) built as Kafka-based FastAPI microservices. Built the platform service registry: registration and deregistration, TTL heartbeats and health status, capability and instance management, and dependency validation so a tenant can safely enable a service such as inventory or CRM.

    • Service registry delivered, measured by tenant-facing enablement with dependency checks
    • Hired on a system-design interview, measured by multi-tenant data synchronisation
    • Python
    • FastAPI
    • Kafka
    • Microservices
    • Docker
  4. 20246 months · remote, Kuwait

    Backend Engineer

    Sulalavia Mereb Technologies

    Early-stage animal management and marketplace app for the Gulf: listings, buyer and seller flows, veterinarian booking and pet groceries. Django/DRF on PostgreSQL and Redis, Celery workers for notifications, email, uploads and heavy queries.

    • 85% test coverage, measured by Pytest, gated in CI
    • 450 users, ~1k req/day, measured by pre-launch scale, stated as is
    • Python
    • Django / DRF
    • Celery
    • PostgreSQL
    • Redis
    • Pytest
  5. 20237 months · Addis Ababa

    Full-Stack Engineer

    Siinqee Bank

    Telegram bot and React dashboard for branch technical-issue tracking, used by 500+ branch managers. Gave head-office technicians visibility into issues that previously went untracked. Ansible and Docker for server configuration and deployments.

    • 500+ branch managers on the bot, measured by adoption across branches
    • Issues tracked end to end, measured by previously lost between branch and head office
    • Python
    • Telegram Bot API
    • React
    • Ansible
    • Docker
  6. 2022 – 20238 months · Addis Ababa

    Junior Full-Stack Developer

    EagleLion System Technology

    React and TypeScript features, REST APIs and role-based BI dashboards for internal finance workflows. Docker dev environments and GitHub Actions CI.

      • TypeScript
      • React
      • REST
      • GitHub Actions
      • Docker
    TAB. 2

    Specification

    underlined = daily driver
    Pythonservices, workers, AI pipelines
    FastAPIPytestDjango / DRFCeleryKafka consumersasync workers
    Years: 4
    Goproduction tooling at Real Gaming
    CLI toolingTerraform wrapperMySQL → ClickHouse pipelineAWS Encryption SDKVault client
    Years: 1
    TypeScript & Nodeproduct services and the UIs on top
    Express.jsTypeScriptNext.jsVitest
    Years: 4
    API & architecture
    RESTOpenAPIgRPCmicroservicesevent-drivenmulti-tenant
    Years: 4
    Data & search
    PostgreSQLRedisMySQLClickHouseTypesense
    Years: 4
    Messaging
    RabbitMQKafkaCeleryidempotent consumers
    Years: 3
    Cloud & infra
    AWS ECS / FargateTerraformECR · S3 · CloudFront · KMSAnsibleDocker SwarmGCPHetzner
    Years: 4
    Security
    HashiCorp Vaultcredential rotationenvelope encryptionKYC / AML workflows
    Years: 1
    Observabilityself-hosted, replaced Datadog
    ClickHouse + HyperDXSlack alertingstructured loggingdashboards
    Years: 1
    Payments
    BraintreeStripeHyperwalletPlaididempotencyreconciliationchargebacks
    Years: 1
    AI & LLM
    OpenAI APILangChainstructured extractionretry + review queues
    Years: 1
    Frontend
    ReactNext.jsTanStack Query / TableZustandTailwind
    Years: 4