MONOPOLY — Technology Decision Matrix

Table of Contents

1. Database Selection
2. Cache Selection
3. Message Queue / Event Streaming
4. API Protocol
5. Search Engine
6. Object Storage
7. Container Orchestration
8. Load Balancer
9. Observability Stack
10. CDN

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1. Database Selection

Relational (SQL)

Database	Best For	Avoid When	Scale Ceiling
PostgreSQL	Complex queries, JSONB, GIS, strong consistency, most default use cases	Ultra-high write throughput (>100K writes/s)	~10TB single node; use Citus for horizontal
MySQL / MariaDB	Read-heavy apps, legacy systems, WordPress/Drupal ecosystem	Complex queries, full ACID at scale	~10TB; use Vitess for sharding
CockroachDB	Global distributed SQL, geo-partitioning, multi-region	Simple single-region apps (overkill)	Petabyte-scale
PlanetScale	MySQL-compatible, serverless, branch-based workflow	Complex JOINs (foreign keys removed by design)	Very high — Vitess based
Amazon Aurora	AWS-native apps, managed PostgreSQL/MySQL, high availability	Non-AWS environments	Up to 128TB, 15 replicas

NoSQL

Database	Best For	Avoid When	Scale Ceiling
MongoDB	Flexible schema, document model, prototyping	Financial transactions requiring ACID	Petabyte-scale with sharding
DynamoDB	Key-value at massive scale, AWS-native, serverless, predictable latency	Complex queries, ad-hoc analytics, JOINs	Unlimited (AWS-managed)
Cassandra	Write-heavy, time-series, wide-column, geographically distributed	Read-heavy with complex queries	Petabyte-scale; used at Apple, Netflix
Redis	Cache, sessions, leaderboards, pub/sub, rate limiting	Primary data store for complex models	~1TB per node; cluster for more
Elasticsearch	Full-text search, log aggregation, analytics	Primary database (durability risk)	Petabyte-scale with clusters
InfluxDB	Time-series metrics, IoT, monitoring data	General-purpose data	Very high write throughput
Neo4j	Graph data, social networks, recommendation engines, fraud detection	Non-graph data (overhead not worth it)	Billions of nodes

Decision Framework

Is your data relational (joins, foreign keys, transactions)?
  YES → Start with PostgreSQL
  NO  → Continue below

Is your primary access pattern key-value?
  YES, need extreme scale → DynamoDB or Cassandra
  YES, need speed/cache → Redis

Is your data document-shaped (nested, flexible schema)?
  YES → MongoDB

Is it time-series (metrics, logs, IoT)?
  YES → InfluxDB or TimescaleDB

Is it graph (relationships are the data)?
  YES → Neo4j

Is it search?
  YES → Elasticsearch / OpenSearch

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2. Cache Selection

Technology	Best For	Max Single Node	Cluster Support
Redis	Sessions, leaderboards, pub/sub, complex data structures, Lua scripting	~1TB RAM	Yes (Redis Cluster, Redis Sentinel)
Memcached	Simple key-value, multi-threaded, large object cache	~64GB RAM	Yes (client-side sharding)
Varnish	HTTP reverse proxy cache, full-page caching	RAM bound	Limited
CloudFront / CDN	Static assets, edge caching globally	N/A (distributed)	Built-in global distribution

Default recommendation: Redis — more features, better ecosystem, active development.

Use Memcached only when: you need multi-threading for CPU-bound caching workloads and don't need data structures beyond string.

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3. Message Queue / Event Streaming

Technology	Model	Best For	Throughput	Retention
Apache Kafka	Log-based streaming	Event sourcing, high-throughput pipelines, replay, audit	Millions msg/s	Days to forever
RabbitMQ	AMQP message broker	Task queues, RPC, routing, fanout	50K–100K msg/s	Until consumed
AWS SQS	Managed queue	AWS-native, simple task queue, serverless	Very high (managed)	Up to 14 days
AWS SNS	Pub/sub notification	Fan-out to many subscribers (email, SMS, Lambda, SQS)	Very high (managed)	No retention
Google Pub/Sub	Managed streaming	GCP-native, global, serverless	Very high (managed)	Up to 7 days
Redis Pub/Sub	In-memory pub/sub	Real-time notifications, low latency, fire-and-forget	Very high	None (no retention)
NATS	Lightweight messaging	IoT, microservices, low latency	Very high	JetStream adds retention

Decision Matrix

Need event replay / audit trail?
  YES → Kafka or Kinesis

Need simple task queue with retries and DLQ?
  AWS shop → SQS
  Self-hosted → RabbitMQ

Need real-time pub/sub with no persistence?
  Redis Pub/Sub or NATS

Need fan-out to multiple consumers?
  Kafka (consumer groups) or SNS → SQS fan-out

Need < 5 minutes guaranteed delivery, AWS-native, zero ops?
  SQS

Volume > 1 million messages/second?
  Kafka (self-hosted) or Kinesis (managed)

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4. API Protocol

Protocol	Best For	Avoid When
REST (HTTP/JSON)	Public APIs, CRUD, browser clients, simplicity	Strict typing required; high-performance internal services
GraphQL	Complex client data requirements, mobile (reduce over-fetching), BFF pattern	Simple CRUD; not worth the complexity
gRPC (HTTP/2 + Protobuf)	Internal microservice communication, low latency, strict contracts, streaming	Public browser APIs (needs gRPC-web)
WebSocket	Real-time bidirectional (chat, live dashboards, multiplayer games)	One-way server push (use SSE instead)
SSE (Server-Sent Events)	Server → client push (notifications, live feeds)	Bidirectional communication
GraphQL Subscriptions	Real-time with GraphQL schema consistency	Simple push scenarios

Default recommendation:

• External / public: REST
• Internal service-to-service: gRPC
• Real-time features: WebSocket or SSE

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5. Search Engine

Technology	Best For	Avoid When
Elasticsearch	Full-text search, log analytics (ELK), complex aggregations	Simple lookups; operational overhead is high
OpenSearch	AWS-native Elasticsearch alternative	Non-AWS preferred setups
Typesense	Simple, fast full-text search, typo tolerance, easy ops	Complex aggregations at massive scale
Algolia	Managed search-as-a-service, fast setup, great UI	High volume (expensive); self-hosted preference
Meilisearch	Self-hosted, developer-friendly, fast relevancy	Enterprise-scale analytics
PostgreSQL FTS	Basic full-text search, already using PostgreSQL	High relevancy requirements or large datasets

Rule of thumb: Use PostgreSQL FTS under 1M documents. Move to Typesense or Elasticsearch above that.

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6. Object Storage

Service	Best For	Egress Cost
AWS S3	AWS-native apps, de facto standard, massive ecosystem	$0.09/GB (expensive)
Cloudflare R2	S3-compatible, zero egress cost, global	$0.00 egress
GCS	GCP-native	$0.12/GB
Azure Blob	Azure-native	$0.087/GB
Backblaze B2	Cost-sensitive, S3-compatible	Free with Cloudflare
MinIO	Self-hosted S3-compatible	Self-managed

Cost optimization tip: Use Cloudflare R2 for user-facing media delivery (zero egress). Use S3 for internal/AWS-integrated storage.

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7. Container Orchestration

Technology	Best For	Avoid When
Kubernetes (K8s)	Large teams, complex deployments, multi-cloud, full control	Small teams (ops overhead is very high)
AWS ECS + Fargate	AWS-native, serverless containers, simpler than K8s	Multi-cloud or K8s ecosystem tools needed
AWS EKS	Managed K8s on AWS, best of both	Small teams; Fargate may be enough
GKE (Google)	Best managed K8s, GCP-native, Autopilot mode	Non-GCP environments
Docker Compose	Local dev, small single-server deployments	Production at any meaningful scale
Nomad	HashiCorp ecosystem, simpler than K8s, multi-workload	K8s ecosystem tools required

Startup default: ECS + Fargate (zero cluster management). Scale default: EKS or GKE once team > 5 engineers or services > 10.

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8. Load Balancer

Technology	Layer	Best For
AWS ALB	L7 (HTTP/HTTPS)	AWS apps, path-based routing, WebSocket, HTTP/2
AWS NLB	L4 (TCP/UDP)	Ultra-low latency, static IP, non-HTTP protocols
GCP GLB	L7 global	GCP apps, global anycast, single IP worldwide
Nginx	L4/L7	Self-hosted, reverse proxy, flexible config
HAProxy	L4/L7	High performance self-hosted, advanced routing
Cloudflare	L7 global + DDoS	DDoS protection + CDN + load balancing combined
Traefik	L7	Kubernetes-native, automatic SSL, service discovery

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9. Observability Stack

Metrics

Tool	Best For
Prometheus + Grafana	Self-hosted, open-source, Kubernetes-native
Datadog	Managed, APM + infra + logs unified, expensive
CloudWatch	AWS-native, zero setup, integrated with AWS services
New Relic	APM-focused, good for application-level insights

Logging

Tool	Best For
ELK Stack (Elasticsearch + Logstash + Kibana)	Self-hosted, powerful, high volume
Loki + Grafana	Lightweight, Kubernetes-native, cheap
Splunk	Enterprise, compliance, expensive
AWS CloudWatch Logs	AWS-native, zero setup
Datadog Logs	Unified with metrics, expensive

Distributed Tracing

Tool	Best For
Jaeger	Open-source, Kubernetes-native, OpenTelemetry
Zipkin	Simple, lightweight, good integrations
AWS X-Ray	AWS-native, integrates with Lambda, ECS
Datadog APM	Managed, unified with metrics and logs
Honeycomb	High-cardinality event-based observability

Recommended open-source stack: Prometheus + Grafana + Loki + Jaeger (all integrate via OpenTelemetry) Recommended managed stack: Datadog (expensive but unified) or Grafana Cloud

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10. CDN

Technology	Best For	Edge Locations
Cloudflare	DDoS protection + CDN + DNS, best free tier, edge workers	300+
AWS CloudFront	AWS-native, deep S3 and API GW integration	450+
Akamai	Enterprise, highest performance, expensive	4000+
Fastly	Real-time purging, streaming, VCL customization	90+
Vercel Edge / Netlify	Jamstack, frontend-first, zero config	100+

Default recommendation: Cloudflare for most use cases (best value, DDoS included, free SSL, Workers for edge compute).

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Scale Benchmarks Quick Reference

Technology	Write Throughput	Read Throughput	Notes
PostgreSQL (single)	~10K writes/s	~50K reads/s	With connection pooling
PostgreSQL (replicas)	~10K writes/s	~200K reads/s	4 replicas
MySQL (single)	~15K writes/s	~60K reads/s
Cassandra	~1M writes/s	~500K reads/s	10-node cluster
Redis	~1M ops/s	~1M ops/s	Single node in-memory
Kafka	~1M msgs/s	~1M msgs/s	Per partition
Elasticsearch	~50K docs/s	~10K queries/s	Per node
MongoDB	~50K writes/s	~100K reads/s	Per replica set

All benchmarks are approximate and depend heavily on hardware, payload size, and query complexity.

Limitations

• This is a reference document and may not cover all edge cases. Always verify architectures before production.