What typically happens
Balances are matched by hand, a formula silently swallows a mismatch, and the report looks fine. The discrepancy surfaces weeks later in an audit, a close, or a complaint — long after it was cheap to fix.
Financial & Audit Tooling · Tooltician
Reconciliation that stops on a mismatch instead of hiding it
I build finance and reconciliation workflows that fail closed — they halt on discrepancies, preserve deterministic audit trails, and make review easier — so a wrong number is caught before it becomes an expensive surprise.
All deliverables are in English. Trust-critical work, built with the explicit checks and audit artifacts that finance review actually needs.
Fixed scope, not open-ended hours. Every engagement starts with a free 15-minute call to confirm fit before any quote.
Problem
In finance, a silent wrong answer is worse than a loud failure
Manual reconciliation and ad-hoc spreadsheets tend to fail open: they produce a number even when the inputs do not agree. The error is invisible until it is expensive.
The real asymmetry
A fast spreadsheet feels efficient until it produces a confident wrong number. A fail-closed control that stops and flags costs a little more time per run and far less than the rework, restatement, and trust damage of a silent error.
Approach
Make the system refuse to produce a confident wrong answer
Before building, we define the controls: what must match, what tolerance is allowed, what the system must refuse, and what evidence each run must leave behind. Correctness over convenience.
What this is not
This is not a full ERP or accounting platform, a certified financial audit (I am not a CPA), or tax filing and advice. It is scoped, fail-closed tooling that makes finance work verifiable.
Reconciliation
- Match banks, ledgers, or systems with explicit, documented rules.
- Fail closed on mismatches instead of producing a silent number.
- Tolerances and exceptions handled deliberately, not by accident.
- Reproducible runs that reconcile to the same result every time.
Fail-closed controls
- Validations that halt and flag rather than absorbing bad input.
- Deterministic finance math, not floating-point surprises.
- Clear, reviewable rules a non-author can understand.
- Tests that lock the controls before any change ships.
Audit artifacts
- Deterministic outputs and an audit trail for every run.
- Evidence packaged so review and sign-off are straightforward.
- Versioned rules so changes to logic are traceable.
- Documentation that survives the audit and the handoff.
Process
How a controls build works
Lock the control requirements, build the smallest verifiable system, and leave audit-grade evidence and documentation behind.
Free diagnostic call
A 15-minute call to confirm the reconciliation or control is a fit. No charge, no obligation.
Controls scoping
A short paid discovery that locks what must match, allowed tolerances, what the system must refuse, and required evidence — agreed in writing. The fee is credited toward the build.
Scoped build
Implementation with fail-closed controls, tests, deterministic outputs, and visible progress in GitHub.
Handoff
Audit artifacts, control documentation, setup, and failure modes — so your team runs and reviews it without me on a call.
Plans & pricing
From one reconciliation to a system of financial controls
The natural entry point is Controls Scoping ($390, credited toward the build). Most teams start with one reconciliation flow, then expand to a broader control system as trust requirements grow.
| From $390 Controls Scoping | From $2,400 Scoped Implementation Recommended | From $4,800 Financial Control System | From $390/mo Stabilization Retainer | |
|---|---|---|---|---|
| Free 15-min diagnostic call | ✓ | ✓ | ✓ | ✓ |
| Control spec in writing | ✓ | ✓ | ✓ | — |
| One fail-closed control flow | — | ✓ | ✓ | — |
| Multiple sources reconciled | — | — | ✓ | — |
| Deterministic audit artifacts | — | ✓ | ✓ | ✓ |
| Tested controls & CI | — | ✓ | ✓ | ✓ |
| Documentation + handoff | — | ✓ | ✓ | ✓ |
| Ongoing rule maintenance | — | — | — | ✓ |
From $390
credited to build
Controls Scoping
A written control spec before any build: what must match, tolerances, refusals, and required evidence.
Fee credited toward any build that follows.
- Free 15-min diagnostic call
- Control spec in writing
- Fixed-price build quote
- Credited toward the build
From $2,400
one-time
Scoped Implementation
One reconciliation or control flow built fail-closed, with deterministic outputs and audit artifacts.
Most common starting point.
- Everything in Scoping
- One fail-closed control flow
- Deterministic audit artifacts
- Tested controls
- Documentation + handoff
From $4,800
one-time
Financial Control System
Multiple sources and controls unified into one auditable system with consistent evidence.
- Everything in Scoped Implementation
- Multiple sources reconciled
- Unified audit trail
- Versioned control rules
From $390/mo
per month
Stabilization Retainer
Keep controls current as rules, sources, and requirements evolve, with external review.
Optional. No lock-in.
- Rule & source updates
- New controls
- Audit support
- Priority response
Prices are starting points for clearly scoped work and are confirmed after the scoping step. Trust-critical work is priced accordingly. International USD pricing reflects fully English deliverables and executive-ready audit documentation. The Spanish version is calibrated for the Chilean and Latin American market.
Why Tooltician
Not the same as a spreadsheet that always returns a number
A spreadsheet is happy to be confidently wrong. Tooltician builds systems that would rather stop than mislead you.
Spreadsheet / generic script
- Fails open: produces a number even when inputs do not agree.
- Floating-point and copy errors hide inside formulas.
- No audit trail — you cannot prove what a past run actually did.
- No tests, so a quiet change to logic goes unnoticed.
Tooltician
- Fails closed: halts and flags rather than producing a silent wrong number.
- Deterministic finance math with explicit, reviewable rules.
- Audit artifacts that make review and sign-off straightforward.
- Tested, versioned controls so changes are traceable.
Proof, not promises
Tooltician ships bankrecon (a fail-closed bank reconciliation CLI on PyPI) and Portfolio Manager (deterministic finance math, local-only persistence). The same standards apply to your build.
Use cases
Where this service fits best
Built for finance and operations work where correctness matters more than a slightly faster run.
Bank reconciliation
Matching statements to ledgers by hand, where a fail-closed tool catches mismatches before close.
Cross-system controls
Numbers that must agree across systems, where silent drift is currently absorbed and discovered late.
Audit readiness
A process that needs a defensible trail, where deterministic artifacts make review and sign-off simple.
Deterministic finance math
Calculations that must be exact and reproducible, where floating-point surprises are unacceptable.
Related projects
FAQ
Questions worth answering precisely
How do you price this — hourly or fixed?
Fixed scope, not hourly. After a short scoping step we agree on a fixed price for a clearly defined build. You know the cost before work starts.
Why is this more expensive than the other services?
Trust-critical work carries more responsibility: the cost of a silent error is high, so the controls, tests, and audit artifacts are more rigorous. The pricing reflects that rigor.
Is this a financial audit?
No. I am not a CPA and this is not a certified audit. I build the tooling and controls that make your finance work verifiable and audit-ready — the audit itself stays with your auditor.
What does fail-closed mean here?
It means the system refuses to produce a confident result when inputs do not agree. It halts and flags instead of returning a number that looks fine but is wrong.
Do you need access to financial data?
For scoping, usually a sample or schema is enough. For the build, controlled access to the relevant sources is required, scoped to what the work needs and handled with care.
Why is this priced in USD when the homepage shows UF?
This international service is delivered entirely in English with executive-ready audit documentation, priced in USD for US, UK, and EU clients. The Spanish version is calibrated for the Chilean and Latin American market in UF.
Next step
Start by scoping the controls, not by trusting the spreadsheet
If a reconciliation or control matters enough that a silent error would hurt, the right entry point is a short scoping pass that turns it into a fail-closed build.
Controls scoping — $390
A written control spec: what must match, tolerances, refusals, and required evidence, plus a fixed-price build quote. The fee is credited toward the build.
If scoping shows existing controls are already sound, the document confirms it with evidence — knowing the basics hold is also valuable before an audit or a close. The fee applies regardless, but there are no surprises.
I reconcile by hand Replace manual matching with a fail-closed tool that halts on mismatches and leaves an audit trail. Numbers must agree across systems Build cross-system controls that catch silent drift before it becomes expensive. I need to be audit-ready Deterministic artifacts and documentation that make review and sign-off straightforward.
If you arrived here because a number has to be right, the scope is this: define the controls, build them fail-closed, and leave audit-grade evidence. Fixed price, no open-ended hours.