Before the contract: proposal, sizing and design
Documenting the interfaces, sizing for the peak, the usage tiers, service metrics, the solution summary, the bill of materials, the commercial model, assumptions, the non-standard log, and the pre-contract checklist.
Every unchecked design decision at signature becomes a change request afterwards. The proposal phase is where the cheap decisions are.
Document the interfaces as they are
Capture every interface TRANXACT replaces, keeps or rebuilds — source and target, type, frequency, volume, connectivity, the decision and whether it is in scope.
| Decision | What it costs |
|---|---|
| Retire | Removes an interface, a reconciliation step and a separate SLA from the business case. |
| Keep | Needs an egress allow-list entry, an owner and a test in the migration plan. |
| Rebuild | The same, plus build effort on the customer’s side of the API. |
Sizing: for the peak, not the average
- Discover — modules, entities, users and integrations, from the configurator and discovery workshops.
- Measure — posting volume per day, concurrent users, peaks, document growth, ASK usage.
- Size — choose the usage tier; adjust nodes, database and environments; add Live DR.
- Validate — a load test on non-production at peak volume before go-live (TO_4.12.02, Standard, once).
- Review — capacity review before each peak season and at renewal.
Sizing drivers: posting volume per day, concurrent users, month-end and payroll peaks, document storage growth, number of integrations, ASK usage, Live DR (a full-size second cluster), vault retention.
Usage tiers (starting points, per environment)
| Tier | Typical profile | Production nodes | Production DB (HA) | Test / QA | Dev / training |
|---|---|---|---|---|---|
| S | Single entity, core modules, under 100 users | 3 × 4 vCPU / 16 GB | 4 vCPU / 16 GB, 250 GB | 3 × 4 vCPU / 16 GB (shared); DB 2 vCPU / 8 GB, 250 GB | — |
| M | Multi-entity, 3–5 modules, 100–500 users | 3 × 8 vCPU / 32 GB | 8 vCPU / 64 GB, 1 TB | 3 × 4 vCPU / 16 GB; DB 4 vCPU / 32 GB, 1 TB | Shared with Test; DB 2 vCPU / 16 GB, 500 GB |
| L | Group, 5–7 modules, 500–2,000 users | 5 × 16 vCPU / 64 GB | 16 vCPU / 128 GB, 2 TB | 3 × 8 vCPU / 32 GB; DB 8 vCPU / 64 GB, 2 TB | 3 × 4 vCPU / 16 GB; DB 4 vCPU / 32 GB, 1 TB |
| XL | Enterprise, high transaction volume | Custom | Custom, with read replicas | Custom | Custom |
Tiers are starting points, not limits. There is no fee for exceeding a tier’s user range — but the customer must subscribe to the sizing its usage needs.
Service metrics
| Service | Usage metric | Block | Category |
|---|---|---|---|
| TRANXACT platform subscription (all 7 modules available) | % of audited revenue | 1 | Standard |
| Live DR region | % of platform infrastructure | 1 | Optional |
| Live DR Premium (requires Live DR) | % of platform infrastructure | 1 | Optional |
| Additional non-production environment | Environment | 1 | Optional |
| Capacity extension (nodes / DB / storage), mirrored in Live DR | vCPU · GB | 4 vCPU · 256 GB | Optional |
| Long-term vault retention | Gigabyte | 256 | Optional |
| Log export service (default retention 365 days) | Gigabyte / month | 50 | Optional |
| Customer-managed keys | Flat fee | 1 | Optional |
| ASK AI usage | Transaction | Per use | Standard; priced by engine tier, BYOK billed by the provider |
The solution summary
Attach one to every proposal, so each commercial choice carries its architectural consequence: modules at go-live; legal entities, currencies and languages; cloud provider; primary and Live DR region; usage tier; availability tier; continuity pattern; environments; connectivity; ASK tier and budget; contract term.
The commercial model
| Line | Priced as |
|---|---|
| 1 — TRANXACT licence | A share of annual audited revenue. Not per seat, per module or a fixed fee; it grows with the customer and falls in a hard year. |
| 2 — Cloud infrastructure | The provider’s bill at its list rates. Live DR adds a full-size second region; vault storage is billed separately. |
| 3 — Services and AI | Optional, Additional and Packaged Services per the workbook; ASK per use by engine tier, or BYOK. |
Keep required and optional lines separate in the bill of materials, so the customer sees the price of each continuity and security choice on its own. Configurator figures are indicative on-demand list prices, not a quote.
Assumptions and the non-standard log
Write down every assumption and who agreed it — scope, volumes, continuity, network, identity, migration history, partner test endpoints, which services are bought. Every one that proves false becomes a change request, so review the list with the customer before signature.
Log every requirement outside the reference architecture with its proposed solution, its limits and its R&R impact. Examples from the guide:
| Requirement | Proposed solution | Limitation | R&R impact |
|---|---|---|---|
| All backups kept in-country for 7 years | Long-term vault retention, yearly copies, an in-country vault region | The lock cannot be shortened; billed per GB | Optional |
| Production reachable only from the corporate network | Close the public listener; private connection plus zero-trust for remote users | Adds network build time; remote users need a VPN client | Optional |
| Third-party tax engine inside the cluster | Evaluate under the extension framework; prefer an external API | Customer-supported; excluded from the SLA if approved | Chapter X |
| Monthly DR switchover | Two Additional drills per quarter on top of the Standard one | Charged per drill; 2 weeks’ notice | Additional |
Anything in the non-standard log needs sign-off from the Ledger Architect — and from TRANXACT security where it touches security or the SLA — before it enters the contract.
Checklist: decisions to lock before signature
| Scope & commercial | Live DR & backup | Extensions | Network & security |
|---|---|---|---|
| Modules, entities, currencies, languages | Availability tier | Configuration first | Connectivity option |
| Audited revenue for the licence | Live DR region chosen | API integrations listed | Non-overlapping /22 ranges (+ DR) |
| Cloud account ownership and billing | RPO / RTO agreed for postings | Any in-cluster code reviewed | FQDN, DNS owner, certificate |
| ASK engine tier or BYOK | Vault retention and long-term options | Non-standard requirements logged | SIEM, CMK, residency needs |
| Usage tier and peaks | Offline copy decision | Key assumptions signed off | R&R workbook scoped and shared |
Values marked proposed default are the deployment guide’s recommended starting points. Confirm each one per customer; the contract, order form, SLA and DPA prevail over this page.