An unchecked decision at signature becomes a change request after it. The proposal is where decisions are cheap.
The interfaces, as they are
List every interface TRANXACT replaces, keeps or rebuilds. Retiring one removes an interface, a reconciliation and a separate SLA from the business case. Keeping or rebuilding one needs an egress allow-list entry, an owner and a test in the migration plan.
| Calderwood interface | Type | Decision |
|---|---|---|
| Bank payments and statements | Host-to-host SFTP, hourly | Rebuild |
| Payroll provider | API, per pay run | Keep |
| Legacy CRM → ERP orders | Point-to-point, nightly | Retire |
| Tax / e-invoicing portal | API, real time | Rebuild |
| Shop-floor MES | Events / API over VPN | Keep, phase 2 |
| BI / data warehouse | Scheduled extract over private link | Keep |
| Consolidation spreadsheets | Manual, month-end | Retire |
Size for the peak
- Discover — modules, entities, users and integrations.
- Measure — postings per day, concurrent users, peaks, document growth, ASK usage.
- Size — pick the tier, then adjust nodes, database and environments; add Live DR.
- Validate — a load test on non-production at peak volume before go-live.
- Review — before each peak season, and at renewal.
| Tier | Profile | Production nodes | Production DB (HA) |
|---|---|---|---|
| S | Single entity, core modules, under 100 users | 3 × 4 vCPU / 16 GB | 4 vCPU / 16 GB, 250 GB |
| M | Multi-entity, 3–5 modules, 100–500 users | 3 × 8 vCPU / 32 GB | 8 vCPU / 64 GB, 1 TB |
| L | Group, 5–7 modules, 500–2,000 users | 5 × 16 vCPU / 64 GB | 16 vCPU / 128 GB, 2 TB |
| XL | Enterprise, high volume | Custom | Custom, with read replicas |
Tiers are starting points, not limits. Exceeding a tier’s user range costs no fee, but the customer must subscribe to the sizing its usage needs.
Three cost lines, kept apart
- The TRANXACT licence — a share of annual audited revenue. Not per seat, not per module, not fixed; it grows with the customer and falls in a hard year.
- Cloud infrastructure — the provider’s bill at list rates. Live DR adds a full-size region; vault storage is separate. Reserved capacity typically cuts compute 30–40%.
- Services and AI — Optional, Additional and Packaged Services per the workbook; ASK per use by engine tier, or BYOK.
In the bill of materials, keep required and optional lines separate so each continuity and security choice shows its own price. Configurator figures are indicative list prices, not a quote.
Assumptions and the non-standard log
Write every assumption down with who agreed it — every one that proves false becomes a change request. Log every requirement outside the reference architecture with its solution, its limits and its R&R impact; each needs the Ledger Architect’s sign-off, and TRANXACT security’s when it touches security or the SLA.
Calderwood’s assumptions: peak ≤ 250,000 postings a day at month-end and ≤ 400 concurrent users (agreed with IT); two years of open items and balances migrated, older history archived outside TRANXACT (Finance); partners provide test endpoints during the build (IT); Standard Services only in year 1 (Procurement). Tier M, Live DR, 60 months.
Try it Calderwood’s sizing was based on 180 concurrent users, but its sales team adds 250 field users in year 2. Is there a penalty for exceeding tier M’s range?
No fee for exceeding the user range — tiers are starting points. But Calderwood must subscribe to the sizing its usage needs: if the capacity review shows more nodes or a bigger database are needed, that is a capacity extension by change request (Optional), mirrored in the Live DR region.