Simpro API + AI: Building an AI Agent for Multi-Trade Businesses (2026 Guide)

Search demand for "Simpro AI" is up 400% year over year. That's not noise — it's a tell. Multi-trade businesses running Simpro have figured out that the platform's native automations get them maybe a third of the way there, and the rest is unstructured: emails from clients, photos from sites, supplier PDFs, scope-of-works documents that come in a dozen formats. The thing that closes that gap isn't another module. It's an AI agent that reads the messy stuff and writes structured records into Simpro.

Simpro is built for businesses that are bigger and more complex than the typical AroFlo shop: estimating with hundreds of line items, multi-stage projects, inventory that moves between sites, recurring maintenance contracts, multiple cost centres. The good news for AI integration is that Simpro exposes most of this surface through a well-documented REST API with OAuth 2.0 — meaning a properly designed agent can read and write across the same modules a project manager uses every day.

This guide is the practical version: how to think about the integration, the API constraints worth knowing, the workflows that actually pay off first, and where the limits are.

Why Native Automations Aren't Enough

Simpro's built-in automations cover the rails: triggers on status changes, scheduled reports, templated email sends, recurring invoice generation. They are excellent for the things they were designed for — repeatable internal events that follow a known shape.

What they don't cover is the volume of unstructured input that drives a multi-trade business day to day:

• Quote requests that arrive as a five-paragraph email with a scope-of-works PDF attached
• Supplier invoices that need to be matched against POs and split across three jobs
• Site photos that the field tech sends with a one-line caption
• Variation requests buried in a client email reply that need to land as a Simpro variation record
• Subcontractor quotes that need to be normalised into your cost catalogue

A native automation can't read a PDF, decide which job an invoice belongs to, or extract a variation from a paragraph of client speak. Those are jobs for a language model. The right architecture combines both: native automations for the deterministic rails, an AI agent for the interpretation work.

The Modern Stack: LLM + Simpro REST API

The four-part architecture is the same one we describe in our AroFlo AI agent guide — what changes is the API and the auth model.

1. An LLM (Claude or GPT-4 class) parses the unstructured input. It reads the email, the PDF, the photo caption, and produces a structured object: {quote_id, job_id, line_items[], variations[], approvals_required}.
2. Direct API calls into Simpro create or update the right records using OAuth 2.0–authenticated requests. No screen scraping. No browser automation.
3. A knowledge layer holds your Simpro-specific context: your cost catalogue, your custom fields, your project templates, your standard cost centre allocations, the prefab scopes for your most common job types.
4. A governance layer keeps a project manager in control: a review queue for high-value or low-confidence actions, a full audit log, and rules about which workflows are allowed to run unattended.

The cost shape sits in the same envelope as AroFlo: a focused first build is typically $20k–40k AUD, with LLM API costs of a few hundred dollars a month at typical volumes. Maintenance is mostly prompt and rule updates, not chasing UI breakage.

What the Simpro API Lets You Do

A few things worth knowing when scoping a Simpro integration.

OAuth 2.0 with Authorization Code or Client Credentials flow. Simpro's API uses standard OAuth 2.0. This makes per-tenant deployment straightforward — credentials live with the customer's company, refresh tokens handle long-running agents, and you don't have to invent auth plumbing.

Coverage is wide. The API exposes companies, sites, contacts, customers, employees, jobs (one-off and projects), quotes, invoices, schedules, timesheets, cost centres, catalogue items, custom fields, and file attachments. For most agent workflows, this is enough surface to run end-to-end.

Rate limits are sufficient for typical agent workloads. Simpro publishes per-minute and per-day limits per company. For the workflows that matter — quote triage, invoice matching, job creation from email — even busy companies stay well under the documented ceiling when the integration uses webhooks instead of polling and caches reads where possible.

Webhooks for the major events. Simpro supports webhooks on job, quote, and invoice status changes. This is the right way to trigger an agent — react to a "quote sent" event and start a 5/10/15 day follow-up sequence, instead of polling every quote nightly.

Multi-company instances are the norm. If you operate as a group with multiple companies in one Simpro instance, the agent has to be company-aware from day one. Most platform errors we see in scoping are missing this — designing for one company and discovering during rollout that the customer runs three.

Architecture in Detail

The flow for a representative workflow — "client emails a scope-of-works request, agent creates the Simpro quote draft" — looks like this:

Inbound: A webhook on the shared inbox triggers when a new email lands. The agent downloads the email body, headers, and any attachments (typically a PDF scope-of-works and a few site photos).

Parse: The LLM reads the email and the PDF together. It extracts the client (existing or new), the site address, the requested scope as a list of items, the requested timeline, and any explicit budget constraints. Photos are described and tagged so they can be attached to the quote.

Match: The agent calls Simpro's API to find the existing client and site, or creates them if they don't exist. It looks up the right cost centre based on scope and standard catalogue items based on the parsed line items. Where a parsed item doesn't match the catalogue with high confidence, the item is left unpriced and flagged for review.

Create: The agent creates the quote in Simpro with the matched line items, attaches the photos, sets the cost centre, and assigns the project manager. The quote sits in "draft" status until a human reviews and sends.

Notify: The PM gets a single email — "Draft quote 4137 is ready for your review" — with a link straight to the Simpro quote and a one-line summary of what the agent extracted and what it left blank.

This pattern — parse → match → create → notify — covers about 70% of the workflows worth automating in Simpro. The variation is what gets parsed and which records get written.

Why Simpro Is Easier to Layer AI On Than People Think

Two things make Simpro a particularly good target for an AI agent build.

Structured custom fields. Simpro lets you define typed custom fields on most major entities. This matters more than it sounds: when the agent extracts something the standard schema doesn't have a slot for ("preferred site contact mobile," "after-hours access required," "special insurance requirements"), you don't need to bolt on a separate database. You add a custom field, point the agent at it, done.

The cost catalogue as a knowledge anchor. A well-maintained Simpro cost catalogue is essentially a structured price book — exactly the reference an LLM needs to turn rough scope text into properly priced quote lines. If your catalogue is in good shape, the agent's pricing accuracy will be too. If it isn't, the first month of the engagement is usually catalogue cleanup with the agent flagging gaps as it finds them.

Sibling product alignment with AroFlo. Simpro acquired AroFlo in October 2021. Architecturally the products remain distinct, but the platform thinking around APIs and webhooks is shared. If you operate divisions on both — large commercial work in Simpro, smaller maintenance in AroFlo — the same agent design covers both with platform-specific actions. We cover the AroFlo side in our AroFlo API integration guide, the smaller-shop alternative in our ServiceM8 AI agent guide, and the side-by-side decision framework in our AU trades software AI guide.

For a deeper architecture reference, see our AI agent development guide and the patterns in our workflow automation guide.

Workflows That Earn Their Keep First

The four highest-value workflows for a Simpro shop, in the order most teams should adopt them:

1. Inbound quote request → draft quote. Client emails a request with scope and attachments. Agent extracts the scope, matches catalogue items, drafts the quote with photos attached and the right cost centre selected. PM reviews and sends. Cuts quote turnaround from days to hours and is the single biggest commercial impact in most shops.

2. Supplier invoice triage and matching. Invoice arrives by email. Agent reads the PDF, matches it to the right job and PO in Simpro, flags variances (price drift, missing line items, quantity mismatches), and routes anomalies to the right person. Routine invoices get logged automatically and the AP team's role shifts from data entry to exception handling.

3. Variation capture from client correspondence. Client replies to an email mid-project: "actually can you also do the back fence while you're there?" Agent identifies this as a variation, drafts the variation record in Simpro with rough scope and pricing, and routes it to the PM for confirmation. Stops variations from going un-billed because they were buried in an email reply.

4. Stale-quote follow-ups in your voice. Quote sent 5/10/15 days ago, no client response. Agent drafts a polite nudge in your house tone, attaches a copy of the quote, and parks the draft in your sent-from-me inbox. Most shops add 10–15% to quote conversion in the first quarter.

What You Keep Control Of

Same trust model as any well-designed agent — start strict, loosen as the agent earns it.

Week one: every action lands in a review queue. You approve or reject. The agent's accuracy gets measured per workflow.

Week three or four: workflows where the agent is consistently right are promoted to "auto-execute, log only." High-value or low-confidence actions still hit the review queue. Specifically for Simpro: any quote over a dollar threshold, any new client, any variation that changes project value by more than X%, any invoice with a price variance greater than Y%.

Month three: 70–85% of inbound triage runs unattended. The PM's day shifts from data entry to exception handling and client conversations.

The audit log is the safety net. Every AI decision is reproducible — input email, LLM reasoning, Simpro API calls, response. Cheap insurance, especially when the agent is touching financial records.

Honest Limitations

A few places where the agent will not be the right tool, and shouldn't pretend to be.

Estimating from drawings. Reading a set of construction drawings and producing a take-off is genuinely hard and the failure modes are expensive. Use the agent for the scope text, the email parsing, the catalogue matching — but keep estimating from drawings as a human task with the agent doing the data entry once the estimator has the numbers.

Compliance-sensitive workflows. Anything involving licences, certificates of currency, or regulator-facing reports needs explicit human sign-off. The agent surfaces context; it doesn't close those workflows.

Custom approval chains in complex orgs. If your approval flow involves multiple stakeholders with varying authority, the agent should route, not decide. We've seen otherwise-good builds undermined by an agent quietly approving spend that should have gone to a director.

Replacing project manager judgement. The agent makes PMs faster on data entry and triage. It doesn't replace the phone call when a major variation needs to be discussed with a client, or the site walk when something has gone wrong.

Frequently Asked Questions

Does Simpro have an open API?

Yes. Simpro offers a documented REST API with OAuth 2.0 authentication. Coverage includes companies, sites, customers, jobs, quotes, invoices, schedules, timesheets, cost centres, catalogue items, custom fields, and file attachments. Simpro also supports webhooks on major events like job and quote status changes.

What authentication does the Simpro API use?

The Simpro API uses OAuth 2.0 with Authorization Code or Client Credentials flow. This makes per-tenant integrations straightforward — credentials live with the customer's company, refresh tokens handle long-running agents, and standard OAuth tooling works out of the box.

Can an AI agent automate Simpro quote creation from email?

Yes. The standard pattern is: a webhook on the inbox triggers when a new request lands, the LLM parses the email and any attached scope-of-works documents, the agent matches against the Simpro cost catalogue and creates a draft quote via the REST API. The draft sits in Simpro for human review before it goes to the client.

What is the difference between Simpro and AroFlo for AI integration?

Simpro and AroFlo are sibling products in the Simpro Group since October 2021. Simpro typically suits larger multi-trade businesses with project-heavy work; AroFlo typically suits smaller property-maintenance focused shops. The AI agent architecture is the same — what changes is the API and auth model. Simpro uses OAuth 2.0; AroFlo uses HMAC-SHA256.

How long does it take to build an AI agent on top of Simpro?

A focused first build — quote drafting from inbound email, with a human review queue — typically ships in 5 to 7 weeks for a Simpro deployment because of the cost catalogue and custom field complexity. Adding invoice matching, variation capture, and follow-up sequences is usually another 4 to 6 weeks each. Most shops see meaningful weekly time savings inside the first 30 days of running the first workflow.

Will an AI agent break when Simpro updates its API?

Properly built integrations are resilient to typical Simpro releases. Because the agent uses Simpro's REST API directly rather than driving the user interface, the things that change in a typical Simpro release — UI layout, button names, page flows — have no effect on the integration. API versioning and deprecation is well-managed by Simpro and gives integrators long lead times.

Where to Start

If you're running a Simpro shop and have started to feel the gap between what native automations cover and what your team actually does day to day, the first move is a single workflow scoped tightly. Pick the one that costs you the most hours — usually quote drafting from inbound requests — and build the agent around that workflow only. Once it's earning its keep, the others follow.

Still deciding between platforms? Read our head-to-head AroFlo vs Simpro vs ServiceM8 for the pricing, API, and shop-size breakdown.

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If you're running Simpro across one or more companies in Australia or New Zealand and this maps to your week, we ship this exact architecture as the Simpro Quote Drafting Agent — fixed-price $34,995 AUD, 6-week build. Sandlabs is based in Melbourne and works with multi-trade businesses across the region. Book a 30-minute discovery call or request a free AI audit if you'd rather start with an honest scoping conversation first — we'll tell you whether an agent will move the needle for your business and what it would cost.