Deliverables

flowchart TB
  subgraph sell["Sell"]
    direction LR
    s1["CRM<br/><i>SaaS · Sales</i>"]
    s2["Quoting<br/><i>bespoke · Sales</i>"]
    s3["Pricing A<br/><i>legacy · Sales</i>"]
    s4["Pricing B<br/><i>legacy · Regional</i>"]
  end
  subgraph fulfil["Fulfil"]
    direction LR
    f1["Order Mgmt<br/><i>bespoke · Ops</i>"]
    f2["WMS<br/><i>COTS · Ops</i>"]
    f3["Carrier Portal<br/><i>SaaS · Ops</i>"]
  end
  subgraph support["Support"]
    direction LR
    b1["ERP<br/><i>COTS · Finance</i>"]
    b2["Billing<br/><i>mainframe · Finance</i>"]
    b3["HRIS<br/><i>SaaS · HR</i>"]
    b4["Expenses<br/><i>SaaS · unowned</i>"]
  end
  s3 -.->|"same capability"| s4

flowchart LR
  sales["Sales<br/><i>quote, opportunity, discount</i>"]
  orders["Ordering<br/><i>order, line, fulfilment</i>"]
  billing["Billing<br/><i>invoice, credit note, dunning</i>"]
  ship["Shipping<br/><i>consignment, manifest</i>"]
  legacy["Legacy Mainframe<br/><i>account master</i>"]

  sales -->|"Customer / Supplier"| orders
  orders -->|"Customer / Supplier"| billing
  orders -->|"Published Language"| ship
  legacy -->|"Anti-Corruption Layer"| orders
  billing -.->|"Shared Kernel — party identity"| sales

flowchart TB
  subgraph core["Customer-Facing"]
    direction LR
    c1["Customer<br/>Management"]
    c2["Product &<br/>Catalogue"]
    c3["Order<br/>Capture"]
    c4["Fulfilment"]
  end
  subgraph enable["Enabling"]
    direction LR
    e1["Pricing &<br/>Promotion"]
    e2["Inventory<br/>Management"]
    e3["Payments &<br/>Settlement"]
    e4["Returns &<br/>Claims"]
  end
  subgraph support["Supporting"]
    direction LR
    s1["Finance &<br/>Accounting"]
    s2["Human<br/>Resources"]
    s3["Procurement"]
    s4["Risk &<br/>Compliance"]
  end

flowchart TB
  gw["HTTP Gateway<br/><i>inbound</i>"]
  subgraph svc["Order API — inside the container"]
    direction TB
    ctrl["Order Controller<br/><i>validation, mapping</i>"]
    app["Order Application Service<br/><i>use cases, transactions</i>"]
    dom["Order Domain Model<br/><i>invariants, state rules</i>"]
    repo["Order Repository<br/><i>persistence port</i>"]
    pay["Payment Client<br/><i>anti-corruption adapter</i>"]
    out["Outbox Publisher"]
  end
  db[("PostgreSQL")]
  ext["Payment Provider"]
  bus[["Kafka"]]

  gw --> ctrl --> app
  app --> dom
  app --> repo --> db
  app --> pay --> ext
  app --> out --> db
  out -.->|"relay reads outbox"| bus

flowchart TB
  cust(["Customer"])
  subgraph boundary["Order Management"]
    direction TB
    web["Web Application<br/><i>Next.js</i>"]
    api["Order API<br/><i>Java / Spring Boot</i>"]
    worker["Fulfilment Worker<br/><i>Java / Spring Boot</i>"]
    db[("Order Store<br/><i>PostgreSQL</i>")]
    queue[["Order Events<br/><i>Kafka</i>"]]
    cache[("Session Cache<br/><i>Redis</i>")]
  end
  pay["Payment Gateway"]

  cust -->|"HTTPS"| web
  web -->|"JSON over HTTPS"| api
  api -->|"reads and writes"| db
  api -->|"reads and writes"| cache
  api -->|"publishes"| queue
  queue -->|"consumes"| worker
  worker -->|"reads and writes"| db
  worker -->|"HTTPS"| pay

flowchart LR
  crm["CRM"]
  oms["Order Mgmt"]
  erp["ERP"]
  wms["WMS"]
  bill["Billing<br/><i>mainframe</i>"]
  dw[("Warehouse")]
  ptnr["Partner"]

  crm -->|"I-01 · REST · on demand"| oms
  oms -->|"I-02 · SFTP CSV · nightly"| erp
  oms -->|"I-03 · MQ · near real time"| wms
  wms -->|"I-04 · REST · on demand"| oms
  erp -->|"I-05 · flat file · nightly"| bill
  bill -->|"I-06 · DB link · nightly"| dw
  oms -->|"I-07 · CDC · continuous"| dw
  ptnr -->|"I-08 · AS2 EDI · hourly"| oms
  oms -->|"I-09 · AS2 EDI · hourly"| ptnr

flowchart TB
  cust(["Customer"])
  agent(["Support Agent"])
  sys["Order Management<br/>the system being described"]
  pay["Payment Gateway<br/>external SaaS"]
  erp["ERP<br/>existing on-premises"]
  mail["Email Provider<br/>external SaaS"]
  crm["CRM<br/>external SaaS"]

  cust -->|"places and tracks orders"| sys
  agent -->|"amends and refunds orders"| sys
  sys -->|"authorises and captures"| pay
  sys -->|"posts financial documents"| erp
  sys -->|"sends confirmations"| mail
  sys -->|"reads account and entitlement"| crm

flowchart LR
  s1[("core_banking.accounts<br/><i>source</i>")]
  s2[("payments.transactions<br/><i>source</i>")]
  s3[("crm.customer<br/><i>source</i>")]

  j1{{"job: cdc_ingest<br/><i>hourly</i>"}}
  j2{{"job: conform_party<br/><i>daily 02:00</i>"}}
  j3{{"job: build_balances<br/><i>daily 03:15</i>"}}
  j4{{"job: reg_extract<br/><i>monthly</i>"}}

  r1[("raw.accounts")]
  r2[("raw.transactions")]
  c1[("clean.party")]
  c2[("clean.balance_daily")]
  o1[("report.capital_adequacy")]
  o2["Dashboard:<br/>Treasury Daily"]

  s1 --> j1 --> r1
  s2 --> j1 --> r2
  s3 --> j2
  r1 --> j2 --> c1
  r1 --> j3
  r2 --> j3 --> c2
  c1 --> j3
  c2 --> j4 --> o1
  c2 --> o2

erDiagram
  CUSTOMER ||--o{ ORDER : places
  CUSTOMER ||--o{ ADDRESS : has
  ORDER ||--|{ ORDER_LINE : contains
  ORDER }o--|| ADDRESS : "ships to"
  ORDER ||--o| PAYMENT : "settled by"
  PRODUCT ||--o{ ORDER_LINE : "appears in"
  PRODUCT }o--|| CATEGORY : "belongs to"

  CUSTOMER {
    uuid id PK
    string email UK
    string status
    timestamp created_at
  }
  ORDER {
    uuid id PK
    uuid customer_id FK
    uuid ship_to_id FK
    string status
    numeric total_minor
    string currency
  }
  ORDER_LINE {
    uuid id PK
    uuid order_id FK
    uuid product_id FK
    int quantity
    numeric unit_price_minor
  }
  PAYMENT {
    uuid id PK
    uuid order_id FK
    string provider_ref UK
    string state
  }

flowchart TB
  root["Organisation Root<br/><i>policy: deny unapproved regions</i>"]

  subgraph plat["Platform"]
    direction TB
    ident["Identity<br/><i>directory, privileged access</i>"]
    conn["Connectivity<br/><i>hub VNet/VPC, firewall, DNS, VPN</i>"]
    mgmt["Management<br/><i>logs, backup, monitoring</i>"]
  end

  subgraph land["Landing Zones"]
    direction TB
    subgraph corp["Corporate"]
      p1["Prod A<br/><i>spoke</i>"]
      n1["Non-Prod A<br/><i>spoke</i>"]
    end
    subgraph online["Internet-Facing"]
      p2["Prod B<br/><i>spoke</i>"]
      n2["Non-Prod B<br/><i>spoke</i>"]
    end
  end

  sandbox["Sandbox<br/><i>spend cap, no connectivity, auto-expire</i>"]
  decom["Decommissioned<br/><i>deny all</i>"]

  root --> plat
  root --> land
  root --> sandbox
  root --> decom
  conn --- p1
  conn --- n1
  conn --- p2
  conn --- n2
  mgmt -.->|"diagnostics forwarded"| land
  ident -.->|"roles and groups"| land

gantt
  title Target state — 18 months
  dateFormat YYYY-MM-DD
  axisFormat %b %y

  section Foundation
  Landing zone and connectivity      :done,   f1, 2026-01-01, 60d
  Identity federation                :done,   f2, after f1, 45d
  Observability baseline             :active, f3, after f1, 75d

  section Decouple
  Strangler facade at edge           :active, d1, 2026-03-15, 90d
  Extract order domain               :        d2, after d1, 120d
  Extract pricing domain             :        d3, after d2, 90d
  Retire shared order database       :crit,   d4, after d3, 60d

  section Data
  Ingest to raw zone                 :        a1, 2026-04-01, 75d
  Conformed customer entity          :        a2, after a1, 90d
  Retire nightly extract jobs        :        a3, after a2, 45d

  section Resilience
  Multi-zone for tier 0              :        r1, 2026-06-01, 60d
  Automated failover rehearsal       :        r2, after r1, 45d
  Second region for tier 0           :crit,   r3, after r2, 90d

flowchart TB
  t1["T-7d · Dry run in staging<br/><i>full rehearsal, timed</i><br/>owner: Delivery"]
  t2["T-1d · Freeze changes · verify backups<br/>confirm rota and bridge<br/>owner: Ops"]
  t3["T-0 00:00 · Enable read-only on legacy<br/>owner: Ops"]
  t4["T-0 00:15 · Final delta migration<br/><i>est 90 min · checkpoint at 60</i><br/>owner: Data"]
  t5["T-0 01:45 · Reconcile counts + checksums<br/>owner: Data"]
  g1{"T-0 02:15 · GO / NO-GO<br/><i>criteria: 100% row match,<br/>0 critical defects, all owners present</i>"}
  t6["T-0 02:30 · Repoint DNS + feature flag<br/><i>TTL pre-lowered to 60s</i><br/>owner: Platform"]
  t7["T-0 02:45 · Smoke suite + 10 manual journeys<br/>owner: QA"]
  g2{"T-0 03:30 · Accept or roll back"}
  t8["T-0 03:30 · Open to 10% traffic<br/>owner: Platform"]
  t9["T-0 06:00 · 100% traffic<br/>owner: Platform"]
  t10["T+24h · Hypercare ends<br/>legacy kept read-only 30d"]
  rb(["ROLLBACK · revert DNS<br/>re-enable legacy writes<br/><i>est 20 min</i>"])
  pnr["POINT OF NO RETURN<br/><i>after first write to new system<br/>rollback needs reverse migration</i>"]

  t1 --> t2 --> t3 --> t4 --> t5 --> g1
  g1 -->|"no-go"| rb
  g1 -->|"go"| t6 --> t7 --> g2
  g2 -->|"roll back"| rb
  g2 -->|"accept"| t8 --> t9 --> t10
  t8 -.-> pnr

flowchart LR
  subgraph w0["Wave 0 — Foundation"]
    direction TB
    f1["Landing zone"]
    f2["Connectivity + DNS"]
    f3["Identity federation"]
    f4["Observability + backup"]
  end

  subgraph w1["Wave 1 — Prove it (6 apps)"]
    direction TB
    a1["Internal wiki<br/><i>rehost</i>"]
    a2["Reporting portal<br/><i>rehost</i>"]
    a3["Batch scheduler<br/><i>replatform</i>"]
  end

  subgraph w2["Wave 2 — Bulk (34 apps)"]
    direction TB
    b1["Departmental apps<br/><i>rehost ×26</i>"]
    b2["Shared services<br/><i>replatform ×8</i>"]
  end

  subgraph w3["Wave 3 — Hard cases (9 apps)"]
    direction TB
    c1["Order management<br/><i>refactor</i>"]
    c2["Data warehouse<br/><i>replatform</i>"]
    c3["Partner gateway<br/><i>refactor</i>"]
  end

  subgraph w4["Wave 4 — Exit"]
    direction TB
    d1["Mainframe interfaces<br/><i>replace</i>"]
    d2["Data centre exit<br/><i>contract ends Q3</i>"]
  end

  w0 -->|"platform accepted<br/>by security + ops"| w1
  w1 -->|"runbook proven<br/>rollback rehearsed"| w2
  w2 -->|"shared services live<br/>latency measured"| w3
  w3 -->|"last dependency<br/>severed"| w4

flowchart TB
  subgraph l1["Capabilities delivered"]
    direction LR
    c1["Product<br/>engineering"] --- c2["Data &<br/>analytics"] --- c3["Platform &<br/>infrastructure"] --- c4["Security &<br/>risk"]
  end
  subgraph l2["Organisation"]
    direction LR
    o1["Stream-aligned teams<br/><i>×9 · own build and run</i>"] --- o2["Platform team<br/><i>×1 · paved road</i>"] --- o3["Enabling team<br/><i>×1 · coaching</i>"] --- o4["Architecture chapter<br/><i>federated</i>"]
  end
  subgraph l3["Ways of working"]
    direction LR
    p1["Product-funded<br/><i>not project</i>"] --- p2["You build it<br/>you run it"] --- p3["Continuous<br/>delivery"] --- p4["Design authority<br/><i>advisory + gates</i>"]
  end
  subgraph l4["Governance"]
    direction LR
    g1["ARB<br/><i>off-radar only</i>"] --- g2["Tech radar<br/><i>quarterly</i>"] --- g3["Automated<br/>compliance"] --- g4["Exception<br/>register"]
  end
  subgraph l5["People"]
    direction LR
    s1["Skills gaps<br/><i>SRE ×6 · data eng ×4</i>"] --- s2["Sourcing<br/><i>hire 6 · reskill 4</i>"] --- s3["Career paths<br/><i>IC track added</i>"]
  end
  l1 --> l2 --> l3 --> l4 --> l5

quadrantChart
  title Business value against technical health
  x-axis "Poor technical health" --> "Good technical health"
  y-axis "Low business value" --> "High business value"
  quadrant-1 Invest
  quadrant-2 Migrate or re-engineer
  quadrant-3 Eliminate
  quadrant-4 Tolerate
  "Order management": [0.28, 0.92]
  "Payment gateway": [0.81, 0.95]
  "Customer portal": [0.74, 0.78]
  "Pricing engine": [0.22, 0.84]
  "Mainframe billing": [0.14, 0.88]
  "Legacy CRM": [0.19, 0.34]
  "Reporting portal": [0.31, 0.26]
  "Expenses tool": [0.68, 0.22]
  "Intranet wiki": [0.72, 0.18]
  "Partner gateway": [0.44, 0.66]