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Archetype To Mechanics To Solution Family Cheat Sheet

Archetype To Mechanics To Solution Family Cheat Sheet #

Use this when the archetype is clear but the implementation family is not.

The key idea:

Archetype = problem shape
Mechanics = implementation choices
Solution family = the resulting class of systems

Product Archetypes #

Archetype	Common Mechanics	Resulting Solution Families
`A01 Current-Value Entity`	row/document overwrite, CAS, leader-owned state, WAL, event sourcing	CRUD service, metadata store, config store, entity service (`user profile`, `inventory metadata`, `feature flag row`)
`A02 Relation / Edge`	edge table, adjacency index, fanout projection, uniqueness constraint	graph edge service, follow/share system, membership service (`Twitter follows`, `GitHub stars`, `group membership`)
`A03 Append-Only Child Object`	append log, ordered partition, parent-local index, moderation tombstones	chat log, comments, reviews, event-stream-backed write path (`Slack messages`, `YouTube comments`, `Amazon reviews`)
`A04 Workflow / Lifecycle State`	state machine table, transactional outbox, saga/orchestrator, timers	onboarding flow, approval system, order/payment workflow (`bank signup`, `loan approval`, `order lifecycle`)
`A05 Derived Projection`	CDC, projector workers, materialized views, cache, recompute jobs	feed store, dashboard, analytics view, read-optimized serving layer (`Facebook feed`, `order history`, `driver heatmap`)
`A06 Inventory / Constrained Resource`	guarded decrement, reservation row, partitioned allocator, lock/CAS	booking engine, seat allocator, stock reservation system (`Ticketmaster`, `airline seats`, `hotel rooms`)
`A07 Critical Transaction Process`	double-entry ledger, idempotency keys, transactional outbox, reconciliation	payment processor, ledgered money movement, settlement workflow (`Stripe-like payments`, `bank transfer`, `wallet debit/credit`)
`A08 Time-Bounded Exclusive Allocation`	hold record, TTL/expiry worker, lease, CAS confirm	waitlist claim system, reservation hold system, temporary slot allocation (`restaurant claim window`, `seat hold`, `appointment hold`)
`A09 Future Constraint + Claimable Run`	due-time index, polling scanner, timing wheel, delayed queue, runnable queue	reminder service, scheduler, delayed execution engine (`Google Calendar reminders`, `marketing campaign scheduler`, `delayed payment execution`)
`A10 Frontier + Claimable Run`	partitioned frontier, claim leases, checkpoints, coverage scanner	crawler, migration scanner, ETL backfill, batch coverage system (`web crawler`, `data backfill`, `storage migration scanner`)
`A11 Control Plane + Local Snapshot`	versioned config, snapshot publication, polling/push apply, monotonic versioning	feature flags, config distribution, policy rollout system (`LaunchDarkly-style flags`, `Envoy xDS`, `central policy rollout`)
`A12 Matching / Assignment`	candidate search, scoring, lease/claim, timeout/reassign	rideshare dispatch, matchmaking, courier assignment (`Uber dispatch`, `Tinder matching queue`, `delivery driver assignment`)
`A13 Ranking / Leaderboard`	streaming aggregation, top-k heap, windowed counters, periodic recompute	leaderboard, trending, top-N analytics (`gaming leaderboard`, `Twitter trending`, `top products dashboard`)
`A14 Realtime Fanout`	websocket sessions, broker/pub-sub, append log plus fanout workers, presence registry	chat delivery, live comments, realtime notifications (`Slack delivery`, `live sports comments`, `presence updates`)
`A15 Search-First Product`	inverted index, shard fanout, indexing pipeline, cache	search engine, nearby search, retrieval system (`Yelp search`, `Google Search`, `RAG retrieval`)
`A16 Auction / Competitive Window`	append bid log, current-best state, close-time finalizer, fencing	auction platform, bidding engine, spot-market allocation (`eBay auctions`, `ad bidding`, `EC2 spot bidding`)
`A17 Shared Mutable Subject`	single sequencer, OT, CRDT, op log plus snapshot, shard ownership	Google Docs, whiteboard, collaborative editor (`Google Docs`, `Figma`, `Miro`)
`A18 Versioned Namespace + Immutable Content Units`	immutable blobs, manifests, head-pointer CAS, dedup, sync changelog	Drive/Dropbox, artifact registry, object/version store (`Google Drive`, `Dropbox`, `Docker registry`)
`A19 Catalog + Scoped Relation`	definition store, scoped attach table, projection/index, policy inheritance	product catalog, tagging/policy attachment, scoped config/catalog systems (`Instacart catalog`, `Atlassian tagging`, `menu-by-store`)

Infrastructure Archetypes #

Infra Archetype	Common Mechanics	Resulting Solution Families
`I01 Coordination / Consensus Metadata`	quorum replication, leader election, watches, revisions	etcd/ZooKeeper-style metadata plane, shard ownership service (`etcd`, `ZooKeeper`, `Consul`)
`I02 Claim / Lease / Exclusive Ownership`	lease table, TTL, renewals, fencing epochs	distributed lock, worker claim service, exclusive-owner control (`Chubby lock`, `Redis lease`, `scheduler job claim`)
`I03 Due-Time Release + Claimable Run`	schedule index, due scanner, delayed queue, runnable materialization	scheduler core, retry engine, reminder release service (`Quartz`, `Celery ETA tasks`, `reminder service`)
`I04 Frontier Scan + Claimable Run`	frontier partitions, checkpoints, batch claims, resumable scans	crawler control plane, migration scanner, backfill engine (`Google crawler control`, `data migration scanner`, `MapReduce input split scanner`)
`I05 Append Log + Consumer Progress`	replicated log, offsets, consumer groups, replay	Kafka-like log, CDC transport, durable event backbone (`Kafka`, `Pulsar`, `Debezium/Kafka CDC`)
`I06 Projection / Index / Search Pipeline`	CDC/outbox, indexers, rebuild jobs, shard fanout	search indexing, feed projection, derived read-model pipeline (`Elasticsearch indexing`, `feed fanout pipeline`, `materialized view projector`)
`I07 Cache / Origin Projection / Edge Delivery`	TTL cache, write-through/back, invalidation, CDN	distributed cache, edge cache, origin shielding (`Redis cache`, `Memcached tier`, `Cloudflare CDN`)
`I08 Rate Limit / Budget / Token Accounting`	token bucket, sliding window, local snapshots, centralized budgets	API rate limiter, quota service, spend control (`API gateway limiter`, `Stripe quota`, `cloud budget enforcement`)
`I09 Sequence / Identifier Generation`	counters, range leasing, worker-id assignment, epochs	Snowflake-like ID service, sequence allocator (`Twitter Snowflake`, `DB sequence service`, `range-leased ID allocator`)
`I10 Membership / Presence / Registry`	heartbeats, soft-state expiry, watch streams, registries	service discovery, presence service, room membership (`Consul service registry`, `Slack presence`, `chat room membership`)
`I11 Control Plane + Snapshot Distribution`	config store, snapshot publish, versioned apply	feature-flag infra, control-plane rollout, agent config distribution (`LaunchDarkly infra`, `Envoy xDS`, `Kubernetes config propagation`)
`I12 Workflow + External Side Effect`	outbox, retries, reconciliation, effect logs	webhook engine, external action orchestration, integration workflow (`Stripe webhooks`, `Zapier-style workflow`, `email delivery workflow`)
`I13 Shared Subject Coordination`	sequencer, op log, versioning, subscribers	collaborative infra core, shared-state coordinator (`Docs backend coordinator`, `Figma multiplayer core`, `shared whiteboard engine`)
`I14 Immutable Artifact Namespace + Delivery`	manifests, immutable blobs, namespace heads, CDN	package registry, image registry, artifact distribution (`npm`, `Docker Hub`, `Maven Central`)
`I15 Execution Fleet + Worker Substrate`	placement, leases, heartbeats, runtime slots, warm pools	Lambda/GitHub Actions runner fleet, batch execution substrate, job runner cluster (`AWS Lambda`, `GitHub Actions runners`, `Kubernetes job workers`)

Usage Rule #

For any prompt:

identify the archetype
choose the mechanics that fit the NFRs
draw the resulting solution family

The same archetype can produce very different designs once the mechanics change.