Custom Software for Professional Services — Stop Leaking Revenue Between Tools

Agencies, consultancies, and professional firms run on a deceptively simple equation: bill more of the hours you work, at a healthy rate, against well-scoped projects. Yet most firms run that equation across four or five disconnected tools — time in one app, projects in another, invoicing in a third, a CRM that knows none of it, and a spreadsheet stitching it together at month-end. Revenue leaks through every seam: hours that never got logged, scope creep nobody flagged, retainers under-consumed or blown through unnoticed.

We build the system that closes those seams. Time capture that flows into billing and into real-time profitability. Project tracking that surfaces scope creep before it becomes a write-off. A client portal that cuts the email overhead. Resource planning that shows who is over- and under-allocated next month. When time, projects, billing, and clients share one source of truth, utilization goes up, realization goes up, and the month-end reconciliation stops being a fire drill.

The unit of production is time, which makes the metrics unlike any product business. Utilization, realization, effective rate, project margin, and backlog are the numbers that determine whether the firm is healthy, and they depend on accurate time capture tied to projects, rate cards, and engagement terms. Generic project tools track tasks but not profitability; generic accounting tools track invoices but not the work behind them. The firm needs both, connected, or it is flying blind on the only economics that matter.

The engagement structures add complexity. A single client might have a monthly retainer, a fixed-fee project, and a time-and-materials change order running at once, each with different billing logic and revenue recognition. Multiply that across a client base and the billing engine becomes the hard part of the build. We have modeled retainers, draw-downs, milestone billing, and blended-rate teams before, and we know the edge cases — the under-consumed retainer, the project that crosses a fiscal boundary, the rate change mid-engagement.

SOC 2 for enterprise clients. Enterprise buyers increasingly will not engage an agency or consultancy without a SOC 2 report, because your firm becomes part of their vendor risk. We build with Common Criteria in mind — encryption at rest and in transit, RBAC, change management, immutable audit logging — and coordinate with your auditor on evidence collection.

Client-data sensitivity. Professional firms hold strategy documents, financials, unreleased product details, and often credentials to client systems. That concentration of sensitive material is exactly what attackers want. We enforce least-privilege access, isolate client data, and log who accessed what so a confidentiality question has an answer.

Client portal access control. A portal where one client can see another's engagement is a confidentiality breach and a reputation killer. We build multi-client isolation carefully and test the authorization boundaries that separate one client's data from the next.

PCI-DSS for client payments. Card data for retainers and invoices is tokenized through Stripe so your environment stays in the lightest PCI scope and raw card numbers never touch your servers.

Contractual confidentiality obligations. Your client MSAs likely impose specific data-handling and breach-notification terms. We do not give legal advice, but we build the access controls, audit trails, and data-segregation your contracts and your clients' security teams will expect.

Next.js 16 on the App Router with React and TypeScript end-to-end for the internal system and the client portal. Postgres for the system of record, with the relational model fitting the time-project-client-invoice relationships cleanly. Prisma or Drizzle as the type-safe ORM. Stripe for retainer and project billing so PCI scope stays light, with QuickBooks Online or Xero sync for the books.

Background workers (Inngest or BullMQ on Redis) handle invoice generation, billing runs, and profitability rollups. Role-based access is wired through every surface, with strict multi-client isolation on the portal. Auth0, Clerk, or a Lucia-style stack for authentication, with MFA on internal accounts that touch financials. Sentry plus a log aggregator for observability, with client-data redaction in the logger. The web tier deploys to Vercel; the data plane moves to a hardened VPC when a SOC 2 or enterprise client requires it.

First, treating time tracking as a standalone tool. A timer disconnected from projects and billing produces data nobody reconciles, and the firm still cannot answer what its realization rate is. Time has to flow into billing and profitability automatically, or it is just another app people forget to fill in.

Second, underestimating the billing engine. Retainers, draw-downs, fixed fee, time-and-materials, milestones, and blended rates each carry their own logic, and the edge cases — the under-consumed retainer, the mid-engagement rate change, the project crossing a fiscal year — are where the real work lives. Teams budget for invoicing and discover billing is the hard part.

Third, weak client-portal isolation. The fastest way to lose a client is to let them glimpse another client's data. Multi-client authorization has to be designed and tested deliberately, not assumed because the query happened to filter by client ID in the demo.

Your operating system holds your firm's financials and your clients' confidential data — the two things you least want on an anonymous contractor's laptop overseas. And as a services firm yourself, you know the difference between a senior who owns the outcome and a body filling a seat. We are US-based and founder-led, and you work with the person who actually designs your billing engine and your client-data boundaries.

William Beltz writes or reviews every line that touches your time data, your billing, and your client information. NDAs are mutual and signed before discovery. Source code lives in your GitHub organization, not ours. The handoff is documented for either ongoing collaboration or in-house ownership — your call.

Agencies and consultancies are targeted precisely because they hold concentrated client data and often credentials into client environments — making them a stepping stone in supply-chain attacks. We run penetration tests mapped to the MITRE ATT&CK techniques those attackers use, then deliver a heatmap of which techniques succeed, which get detected, and which get blocked.

For the client portal, internal platform, and billing surfaces that carry sensitive data, web application penetration testing covers authentication, multi-client isolation, and the authorization boundaries that keep one client's data away from another. Every finding maps to ATT&CK technique IDs so your team knows what to alert on.