Contractors Assistant — Case Study

Case Study: Contractors AssistantIndustry: Field services & trades (HVAC, electrical, plumbing, landscaping, and more)
Product type: Multi-tenant SaaS · Progressive Web App (PWA)
Built by: MonthosAt a glance

What we built

An end-to-end operations platform for contractor businesses—from first quote to on-site execution, client communication, invoicing, and analytics.

Who it’s for

Owner-operators, office managers, sales teams, and field technicians working across residential and commercial jobs.

Platform

Mobile-first PWA with full desktop support; installable on phones and tablets for technicians in the field.

Deployment

Production on Netlify with Supabase backend, Edge Functions, and row-level security across all tenant data.

Project impact

Monthos built a contractor operating system that carries a job from first quote to on-site proof to invoice—on one mobile-first platform.

Quotes clients can actually picture. AI-assisted quoting and AI image editing produce visual proposals, with versioning and engagement signals.

Scheduling that prevents conflicts. Technician-aware booking blocks double-bookings, and accepted quotes convert straight to scheduled jobs.

Proof that isn't lost in a camera roll. Mandatory, job-linked photos, documents and voice notes create an audit-friendly record tied to invoicing.

Transparency without surveillance. Clients get ETA-only progress links—no live GPS tracking—backed by tenant-isolated data with row-level security.

Who this is for: field-service and trades businesses (HVAC, electrical, plumbing, landscaping and more)—owner-operators, office managers, sales teams and field technicians.The challengeContractor businesses often run on a patchwork of spreadsheets, messaging apps, paper checklists, and generic CRM tools that were never designed for how trades actually work. That creates predictable pain:

Quotes take too long and don’t show clients what the finished job will look like.

Scheduling is fragile—double-booked technicians, unclear job status, and no single view of the week.

On-site work lacks structure—evidence is scattered across camera rolls and chat threads.

Client communication feels opaque—customers want updates without invasive live tracking.

Finance is disconnected—quotes, job completion, and invoicing live in different systems.

Multi-company teams need guardrails—sales staff may work across businesses, but field labour must stay scoped to one company at a time.

The goal was not another generic project-management tool. The goal was a purpose-built contractor operating system: fast on mobile, trustworthy for clients, secure for multi-tenant data, and smart enough to use AI where it genuinely helps—without replacing human judgment.Our approachMonthos partnered on product definition, UX, and full-stack delivery using a phased blueprint: foundation and tenancy first, then CRM and maps, quotes and jobs, evidence and AI, client portals, finance, analytics, and PWA hardening.Three principles guided every decision:

Mobile-first for technicians, solid on desktop for managers — bottom-tab navigation on phones, structured dashboards on larger screens, and a calm enterprise visual language (teal brand, card-based layouts, status chips, KPI tiles).

Rules first, AI second — system checks and mandatory evidence rules are enforced in the product; AI assists with quoting and visual proposals but always remains editable by the user.

Trust by design — multi-tenant isolation via Supabase RLS, immutable audit logs, ETA-only client updates (no live technician tracking), and zero admin impersonation.

What we deliveredClient & site management (CRM)A contractor-native CRM supporting residential and commercial clients:

Client cards with search and filters

Multi-site commercial accounts with site-level contacts and billing context

Google Maps–powered location pins with radius, duplicate warnings, and primary/last-used tags

Site lifecycle (inactive sites hidden from new jobs but preserved in history)

Quotes, versioning, and visual sellingVersioned quotes with a clear status flow (Draft → Sent → Viewed → Accepted / Rejected / Expired):

Line items, materials, and trade-specific service types seeded by contractor category (plumbing, electrical, HVAC, etc.)

AI quote assistant (Google Gemini) to draft quotes from natural language—draft-first, always editable

AI image editing inside quote media: mask areas, prompt changes (e.g. show an air-conditioning unit on a wall), generate option versions, mark a recommended option, and link options to line items

Visual Proposals—shareable client views and PDF exports generated from the quote, not as a separate document silo

Client portal links for quote review and engagement signals

Jobs, scheduling, and field executionAccepted quotes convert automatically to jobs. Scheduling follows a deliberate flow:

Choose technicians

Set hours required

Pick a date

Select an available slot (double-booked technicians are blocked with clear busy indicators)

On site, technicians confirm arrival before task steps and checklists appear. Mandatory evidence (photos, documents, voice notes) is enforced with clear UX when required items cannot be removed.Additional field features:

En-route and on-site job execution with timeline history

Map + list patterns for navigation to pins

Job types: quote assessment, implementation, warranty assessment

Invoice readiness checks and dispute pack export when work is complete

Client-facing portals (privacy-conscious)Shared links give clients visibility without over-sharing:

Job progress page with ETA refreshes (approximately every five minutes)—no live GPS tracking

ETA stops once all assigned technicians have arrived

Quote and visual proposal portals for review and acceptance

Staff, teams, and permissionsEnterprise-grade access control for growing contractor businesses:

Role-based permissions (technician, admin, finance, manager, procurement, sales, and more)

Teams, invitations, leave tracking, and wage settings per tenant

Labour-role constraint: users with field/labour roles cannot belong to multiple companies—preventing scheduling and payroll conflicts

Audit logs for accountability

Finance and integrations

Invoicing workflow with readiness gates tied to job evidence

Optional Xero sync (can be disabled per tenant)

Email delivery via SendGrid Edge Functions for quotes, invoices, and notifications

Analytics and reportingOperations dashboards with:

Simple view: top KPIs and health badges for day-to-day use

Advanced view: filters, trends, regional breakdowns, confidence thresholds, deep-link sharing, and CSV/PDF export

Quote funnel metrics (sent, viewed, accepted, rejected) and job/revenue trends

Progressive Web AppInstallable PWA with offline-oriented architecture—technicians can add the app to their home screen and work reliably in the field.Technical highlights

Layer

Technology

Frontend

React 18, TypeScript, Vite, Tailwind CSS, TanStack Query, React Router

Radix UI primitives, Recharts, mobile-first responsive layouts

Backend

Supabase (PostgreSQL, Auth, Storage, Edge Functions)

Security

Row-level security (default-deny), tenant-scoped policies, immutable audit log

Auth

Email/password plus Google and Microsoft SSO

Maps

Google Maps Platform (Places, geocoding, distance/ETA)

Google Gemini (quote assistant, AI image editing via Supabase Edge Functions)

Documents

React PDF generation for quotes, visual proposals, and analytics exports

Email

SendGrid via Supabase Edge Functions

Accounting

Optional Xero integration

Hosting

Netlify (static SPA) + Supabase cloud

Quality

Vitest unit tests, Playwright E2E, GitHub Actions CI, MSW for API mocking

Architecture decisions that matter for scale and compliance:

Multi-tenant isolation enforced at the database layer—not only in application code

Edge Functions for sensitive operations (AI calls, PDF generation, outbound email) keeping secrets off the client

Versioned quotes and media so client-facing documents stay aligned with internal job records

Phased delivery across 18 modules—from foundation through PWA and security hardening—so each layer could be tested before the next was built

OutcomesContractors Assistant gives trade businesses a single system for the workflows that actually define their day:

Before

After

Quotes built in documents and email threads

Structured, versioned quotes with AI drafting and visual options clients can understand

Scheduling conflicts discovered on the day

Technician-aware scheduling with blocked slots and overlap warnings

Evidence in personal photo libraries

Mandatory, job-linked attachments with audit-friendly history

Clients calling for “where are they?” updates

Shareable progress links with ETA-only updates—respectful and clear

Finance disconnected from field work

Invoice readiness tied to job completion; optional Xero sync

Generic tools with weak permission models

Trade-specific templates, RBAC, and labour-role tenancy rules

The platform is live as a production SaaS deployment, with CI/CD, load-testing scripts, and documentation for environment setup, Supabase migrations, and Edge Function deployment.Why this project matters for trades SaaSMost software in this space optimises for the back office or the field crew—not both. Contractors Assistant was designed around the full job lifecycle and the trust boundaries that matter to contractors and their customers:

Technicians need speed and clarity on site.

Managers need scheduling, evidence, and reporting without chasing updates.

Clients need transparency without surveillance.

The business needs tenant-safe data, auditability, and optional accounting integration.

That combination—operations depth, client-facing polish, and enterprise security in a mobile PWA—is what makes this a strong reference build for field-service and trades platforms.Services demonstratedThis project showcases Monthos capabilities across:

Product strategy & specification — trade-specific workflows, RBAC model, client privacy rules

UX/UI design — mobile-first PWA, design tokens, dark/light modes, contractor-native patterns

Full-stack SaaS engineering — React, Supabase, Edge Functions, integrations

AI feature integration — Gemini-powered quoting and image editing with human-in-the-loop controls

DevOps & quality — Netlify deployment, CI pipeline, E2E and unit test coverage

Get in touchBuilding a vertical SaaS product for field teams, trades, or operations-heavy businesses?Talk to Monthos →We design and ship mobile-first platforms that your users will actually adopt—secure, integrated, and built to scale.Case study prepared for Monthos.com. Product: Contractors Assistant. All product names and trademarks belong to their respective owners.Monthos Group — Cheltondale, Johannesburg, SA. Email info@monthos.com, phone +27 (68) 750 7313.Case studies · Privacy Policy · Terms of Service