AI Automation/Financial Advising

Detect Fraudulent Expenses with a Custom AI System

AI detects fraudulent expenses by learning normal spending patterns from your historical data. It flags transactions that deviate from these patterns, catching anomalies rules-based systems miss.

By Parker Gawne, Founder at Syntora|Updated Mar 13, 2026

Key Takeaways

  • AI detects fraudulent expenses by learning your unique spending patterns and flagging deviations.
  • Off-the-shelf tools use simple rules that miss subtle or recurring fraud.
  • A custom system connects directly to your bank via Plaid and can be built in 3 weeks.
  • Syntora has built financial integrations that process bank data syncs in under 3 seconds.

Syntora builds custom AI systems for small businesses to detect financial anomalies. Syntora built financial APIs connecting Plaid and Stripe to a PostgreSQL ledger for real-time transaction monitoring. This system automates categorization and processes bank syncs in under 3 seconds.

A custom system's complexity depends on the number of data sources. Integrating Plaid for bank transactions and Stripe for payments is a common starting point. Syntora has built these financial integrations, connecting bank data to a PostgreSQL ledger to provide real-time transaction monitoring and automated categorization.

The Problem

Why Do Finance Teams Still Miss Fraudulent Expenses?

Most small businesses use tools like QuickBooks Online or Expensify for expense management. These systems rely on manually configured rules, such as flagging any transaction over $500. This approach cannot detect a pattern of ten fraudulent $499 transactions from the same employee, as each one falls below the threshold. The logic is rigid and lacks the context of historical behavior.

Newer platforms like Ramp offer more controls but are limited to their own corporate card ecosystem. The platform is blind to fraudulent reimbursements paid from a company bank account or suspicious activity on other payment platforms. If an employee submits an out-of-pocket expense claim, Ramp has no data to cross-reference its validity against other spending, creating a significant blind spot.

Consider a 20-person firm where an employee submits five separate expense reports for "client entertainment" under the $100 auto-approval limit, all on the same day. A rule-based system approves each one because they are evaluated independently. An AI-based system would see this as a high-frequency anomaly from a single user in a short time frame and flag it for manual review. The core problem is that off-the-shelf tools treat each expense as a discrete event. They are not architected to analyze transaction sequences, vendor frequency, or spending velocity across your entire financial footprint.

Our Approach

How Syntora Builds a Custom AI Anomaly Detection System

The first step is a data audit of your existing financial stack. Syntora connects to your bank accounts via Plaid, your payment processors like Stripe, and any existing expense software. This process maps every source of spend into a single, unified view. Syntora has built these exact integrations before, creating a custom PostgreSQL ledger that provided automated transaction categorization and real-time balance tracking.

For anomaly detection, this unified data feed is used to train a model. We would use Python with scikit-learn to build an Isolation Forest model, which is highly effective at identifying outliers in financial data. The model runs on a schedule as an AWS Lambda function, scoring each new transaction. Transactions with a high anomaly score trigger an alert with a detailed explanation, delivered directly to you via Slack or email. The total hosting cost for this is typically under $25 per month.

The delivered system is a set of serverless functions and a database that you own completely. It operates in the background, pulling new transactions, scoring them in near real-time, and pushing actionable alerts into your existing workflow. Based on our past financial integration work, a bank sync takes under 3 seconds, and the added anomaly scoring would add less than 500ms of processing time. The standard build for this system is a 3-week engagement.

Rule-Based Expense SoftwareCustom AI Detection System
Fixed rules (e.g., amount > $500)Pattern analysis (e.g., unusual vendor, time, or frequency)
Limited to one platform (e.g., only corporate card spend)Unified view across all sources (bank accounts, cards, payments)
High rate of false positives on legitimate large purchasesLow false positive rate by understanding context

Why It Matters

Key Benefits

01

One Engineer, Call to Code

The engineer on your discovery call is the one who builds and deploys your system. No project managers, no communication gaps.

02

You Own the System and Code

You receive the full source code in your GitHub repository and a maintenance runbook. There is no vendor lock-in or recurring license fee.

03

A 3-Week Production Timeline

For a standard integration with Plaid and one other payment source, a working detection model can be live in three weeks.

04

Defined Post-Launch Support

An optional monthly retainer covers model monitoring, retraining, and system updates for a flat fee. You know exactly who to call.

05

Finance-Specific Engineering

Syntora has direct experience building financial systems using Plaid, Stripe, and PostgreSQL, focusing on transaction integrity and real-time processing.

How We Deliver

The Process

01

Discovery Call

A 30-minute call to understand your payment sources, current expense tools, and specific fraud concerns. You receive a scope document outlining the approach and timeline within 48 hours.

02

Data and Architecture Review

You provide read-only access to financial data sources. Syntora audits the data quality and presents a technical architecture for your approval before the build begins.

03

Build and Weekly Demos

You get weekly updates and see working software that flags anomalies in your actual data. Your feedback is incorporated before final deployment.

04

Handoff and Training

You receive the complete source code, a deployment runbook, and a training session on how to interpret alerts and monitor the system's performance.

The Syntora Advantage

Not all AI partners are built the same.

AI Audit First

Other Agencies

Assessment phase is often skipped or abbreviated

Syntora

Syntora

We assess your business before we build anything

Private AI

Other Agencies

Typically built on shared, third-party platforms

Syntora

Syntora

Fully private systems. Your data never leaves your environment

Your Tools

Other Agencies

May require new software purchases or migrations

Syntora

Syntora

Zero disruption to your existing tools and workflows

Team Training

Other Agencies

Training and ongoing support are usually extra

Syntora

Syntora

Full training included. Your team hits the ground running from day one

Ownership

Other Agencies

Code and data often stay on the vendor's platform

Syntora

Syntora

You own everything we build. The systems, the data, all of it. No lock-in

Get Started

Ready to Automate Your Financial Advising Operations?

Book a call to discuss how we can implement ai automation for your financial advising business.

FAQ

Everything You're Thinking. Answered.

01

What determines the price for this kind of system?

02

How long does a typical build take?

03

What happens after you hand the system off?

04

What if we have a low volume of transactions?

05

Why hire Syntora instead of a larger agency or a freelancer?

06

What do we need to provide to get started?