Hosten Growth Partners

Our Product

Mainspring

The operating system for small services businesses.

Project management, invoicing, time tracking, accounts payable, client portals, and an AI advisor — in one place. Built for the kind of small teams who don't have time to wire seven SaaS tools together just to send a clean invoice.

What's inside

One tool, every part of the work.

Projects & tasks

Drag tasks across a Kanban board or zoom out to a Gantt timeline. Multi-task templates spawn entire onboarding flows in one click.

Schedule

Drag-to-reschedule timeline, capacity warnings, and a workload view that surfaces who's overloaded before it's a problem.

Time tracking

Log hours per task. Roll-ups to projects, clients, and invoices.

Invoices

Branded invoices, recurring billing, payments via Stripe, ACH, or check. Export-ready for your accountant.

Bills (AP)

Track vendor bills, schedule payments, generate NACHA files or QuickBooks exports. Receipt scanning via OpenAI Vision.

Client portals

White-label, read-only project view at a private URL. Your colors, your logo — clients never see Mainspring unless you want them to.

Reports

Live revenue, time, expenses, and project health dashboards. Exportable to CSV.

AI advisor

An OpenAI-powered strategy assistant that reads your real numbers and answers questions about cash flow, capacity, and growth.

Who it's for

Small services businesses with one too many spreadsheets and not quite enough hours.

Marketing studios, consultancies, agencies, professional services firms — anyone who runs projects, bills clients, and pays vendors, but isn't big enough to justify NetSuite. Mainspring sits at the seam between a project management tool and a small-business accounting platform, so you don't have to.

Contact

Tell us about your project.

Software, consulting, or both — we read every note.

hello@hostengp.com