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Building a Real-Time Fraud Auditor in Google Chat with BigQuery

By Vo Tu Duc
May 21, 2026
Building a Real-Time Fraud Auditor in Google Chat with BigQuery

High-volume sales events can lead to record-breaking revenue, but the very chaos that drives success also creates the perfect cover for catastrophic fraud and system failure.

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The High-Stakes Challenge of High-Volume Sales Events

High-volume sales events like Black Friday, Cyber Monday, or a product launch are the commercial equivalent of a supernova—an explosive, brilliant burst of energy that can define a company’s entire quarter. They drive massive revenue and attract new customers. However, this immense pressure on both systems and personnel creates a volatile environment where the line between record-breaking success and catastrophic failure is razor-thin. The very conditions that create opportunity also cultivate unprecedented risk.

Why flash sales are a magnet for fraud and system glitches

The chaos of a flash sale is a feature, not a bug, for malicious actors.

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  • Volume as a Smokescreen: When your systems are processing tens of thousands of transactions per minute, identifying a few hundred fraudulent ones in real-time is like trying to spot a specific raindrop in a hurricane. Fraudsters exploit this noise, knowing that their malicious activities are more likely to be lost in the flood of legitimate traffic.

  • Urgency-Driven Exploits: Flash sales thrive on “Fear Of Missing Out” (FOMO). This psychological pressure causes legitimate customers to rush through checkout, often ignoring subtle warning signs. It also forces engineering and fraud teams to prioritize system uptime over meticulous validation, sometimes loosening security rules to ensure the sales funnel remains open. Fraudsters leverage this by using techniques like card testing (probing with stolen card numbers) and account takeovers, betting that the sheer velocity of the event will hide their tracks.

  • System Stress and Emergent Failures: These events push infrastructure to its absolute limits. Code paths that are rarely executed, database connections that are seldom stressed, and third-party API integrations (like payment gateways or shipping calculators) can fail in unpredictable ways. A misconfigured promotion, a race condition in inventory management, or a caching error can suddenly offer products for free or at a 99% discount. These glitches, once discovered, are immediately weaponized by bots and spread across fraud communities, turning a minor bug into a multi-million dollar liability in minutes.

The limitations of traditional batch-based fraud review

For years, the standard approach to fraud analysis has been batch processing. At the end of the hour or the day, transaction logs are collected, loaded into a data warehouse, and analyzed in bulk. While this method is useful for historical reporting and trend analysis, it is fundamentally unsuited for the realities of a high-velocity sales event.

The core issue is latency. In a batch-based world, by the time a fraudulent transaction is flagged, the damage is already irreversible.

Consider this typical timeline:

  • 1:05 PM: A botnet exploits a pricing glitch, ordering 5,000 units of a high-value digital product for pennies on the dollar.

  • 1:06 PM: The digital goods are automatically delivered to thousands of anonymous email addresses.

  • 2:00 AM (Next Day): The nightly batch job runs. The analytics query finally crunches the numbers and identifies the massive sales anomaly.

  • 9:05 AM (Next Day): A human analyst sips their coffee, opens their dashboard, and sees a critical alert from 7 hours ago about an event that concluded 20 hours ago.

At this point, there is no recourse. The product is gone, the perpetrators are untraceable, and the business is left to absorb the full financial loss. The batch system served as a historian of the disaster, not a defense against it.

The financial and reputational cost of a single missed anomaly

In the context of a flash sale, the term “single anomaly” is a misnomer. A single vulnerability—be it a system glitch or a new fraud pattern—is not a single event. It is an exploit that will be replicated at machine scale until it is stopped. The cost of missing that initial signal is therefore magnified exponentially.

  • Direct Financial Loss: This is the most obvious cost. It includes the value of the goods or services lost, the staggering fees associated with chargebacks (which can often exceed the transaction value), and the operational overhead of teams investigating and remediating the incident after the fact.

  • Erosion of Customer Trust: The impact extends far beyond the balance sheet. When legitimate customers have their accounts taken over, or when they are blocked from making a purchase by an overly blunt, reactive fraud system (a common side effect of batch analysis), their trust is broken. A customer who is incorrectly flagged as fraudulent during the year’s biggest sale is not just a lost transaction; they are often a lost customer for life, and a vocal one on social media.

  • Brand Damage: A widely publicized event where a company “accidentally” sold $500 headphones for $5 can become a case study in what not to do. It makes the brand appear incompetent and unreliable, damaging its reputation with customers, partners, and investors. This reputational harm can linger for years, far outlasting the immediate financial hit.

The fundamental challenge is clear: you cannot afford to wait for a post-mortem analysis. The detection and response loop must be compressed from hours or days down to seconds.

The Solution: A Conversational Real-Time Risk Auditor

The traditional approach to fraud detection is a one-way street: a system detects a potential issue and sends an alert to a dashboard or an email inbox. This creates a critical delay—the “detection-to-decision” gap—where financial loss can occur. We’re flipping the script. Instead of forcing analysts to hunt for information across multiple systems, we bring the decision point directly to them in the collaborative environment they already use every day: Google Chat.

This solution transforms a passive notification system into an active, conversational, and decisive risk auditing tool, powered by the analytical muscle of BigQuery and the immediacy of Google Chat.

Introducing the concept: Triage anomalies directly within Google Chat

Imagine this workflow: BigQuery’s real-time analytics and ML models flag a high-risk transaction. Instead of just logging an entry on a dashboard, a purpose-built Google Chat bot instantly springs into action. It delivers a rich, interactive message card directly to the designated fraud analyst or channel.

This isn’t a simple text notification. The card is a self-contained triage unit, presenting all the critical information needed for an initial assessment:

  • Transaction Details: User ID, transaction amount, vendor, timestamp, and item category.

  • Risk Score: The probability score and key contributing factors identified by the BigQuery ML model.

  • Historical Context: A link to the user’s recent transaction history or other relevant dashboards.

  • Action Buttons: A set of clear, decisive actions like “Approve Transaction,” “Flag for Deeper Review,” or “Temporarily Freeze Account.”

The analyst can see the alert, assess the data, and take immediate, decisive action—all without ever leaving their chat window. The conversation with the bot becomes the primary interface for managing risk, collapsing the entire triage process into a single, streamlined interaction.

Core objectives: Speed, accuracy, and decisive action

This conversational approach is built on three fundamental pillars that directly address the shortcomings of traditional fraud alert systems.

  1. Speed: The primary objective is to slash the Mean Time To Resolution (MTTR). By eliminating context switching—the need to open email, log into a separate security portal, search for the transaction ID, and then navigate to another tool to take action—we reduce a process that could take minutes or hours down to mere seconds. When a fraudulent transaction is in flight, this speed is the difference between a logged event and a prevented financial loss.

  2. Accuracy: By presenting a concise, curated view of the data directly from BigQuery, we reduce the potential for human error. The analyst isn’t manually correlating data points from different UIs; they are acting on a single source of truth. The ML model provides a consistent, unbiased initial assessment, ensuring that analysts focus their cognitive energy on the most ambiguous and highest-risk cases, improving the overall accuracy of the human review process.

  3. Decisive Action: Information without the ability to act is just noise. This system is designed to close the loop. The interactive buttons are not just suggestions; they trigger real, automated workflows. Clicking “Freeze Account” can invoke an API call to immediately suspend user privileges. Clicking “Approve” clears the transaction and can even be used to feed data back to the ML model as a correct prediction. This transforms the analyst from a passive monitor into an active, empowered defender.

How this empowers fraud analysts and protects the bottom line for CFOs

The business impact of a real-time, conversational auditor is felt across the organization, from the front-line analyst to the C-suite.

For the Fraud Analyst:

  • Eliminates Alert Fatigue: The system intelligently routes high-confidence alerts, ensuring that analysts aren’t drowning in a sea of low-priority notifications. Their attention is directed where it’s most needed.

  • Streamlines Workflow: By centralizing triage within Google Chat, it removes the friction of tool-hopping and dramatically improves day-to-day operational efficiency.

  • Increases Impact: Analysts can see the immediate result of their actions, making their work more engaging and impactful. They spend less time on repetitive data gathering and more time on strategic investigation of complex fraud patterns.

For the CFO and the Business:

  • Minimizes Financial Loss: This is the most direct benefit. By stopping fraudulent transactions in near real-time, the system directly protects revenue and prevents costly chargebacks and recovery efforts.

  • Improves Operational Scalability: The efficiency gains mean that the existing fraud team can handle a significantly higher volume of transactions without a linear increase in headcount, allowing the business to grow securely.

  • Enhances Governance and Auditability: Every action taken via the Chat bot is logged, creating an immutable, timestamped audit trail. This provides clear accountability and simplifies compliance reporting, demonstrating robust internal controls to auditors and stakeholders.

Architectural Blueprint The Tech Stack in Action

A real-time system is a symphony of specialized components, each playing a critical role. Our fraud auditor is no different. It’s not a single, monolithic application but a distributed system where data flows seamlessly from ingestion to action. Let’s dissect the four core pillars of this architecture and see how they collaborate to create a responsive and intelligent security tool.

Data Foundation: Streaming transaction data into BigQuery

The entire system is anchored in Google BigQuery, our single source of truth for all transaction data. Its serverless, massively parallel architecture makes it the ideal foundation for both real-time analytics and historical analysis. The key isn’t just using BigQuery, but feeding it effectively.

We achieve near-real-time ingestion using a decoupled, event-driven pipeline:

  1. Event Source: Webhooks from platforms like Shopify (orders/create) or Stripe (charge.succeeded) fire off a JSON payload the instant a transaction occurs.

  2. Ingestion Endpoint: These webhooks don’t hit BigQuery directly. Instead, they push events to a Google Cloud Pub/Sub topic. This acts as a durable, scalable buffer, ensuring we never lose an event even if downstream services are temporarily unavailable.

  3. Streaming Ingestion: A lightweight Cloud Function subscribes to the Pub/Sub topic. Upon receiving a new message, it validates the payload, transforms it into our defined schema, and uses the BigQuery Storage Write API to stream the record directly into our master transactions table. This API is purpose-built for high-throughput, low-latency streaming, making data available for querying within seconds.

The result is a perpetually up-to-date table in BigQuery that serves as the high-performance analytical engine for our fraud detection logic.

Orchestration Engine: Leveraging Antigravity 2.0 for workflow [Automated Job Creation in Real Time Jobber and Google Sheets Integration from Gmail](https://votuduc.com/Automated-Job-Creation-in-Jobber-from-Gmail-p115606)

With data flowing into BigQuery, we need a central nervous system to react to it. This is the role of our orchestration engine, Antigravity 2.0. Think of it as a stateful, event-driven workflow manager that connects our components and executes our business logic.

Here’s how it functions as the system’s brain:

  • Triggering: Antigravity is configured to listen for specific events. In our case, it’s triggered by an audit log entry indicating a new row has been streamed into our BigQuery transactions table. This is far more efficient than constantly polling the table.

  • Logic Execution: Once triggered, an Antigravity workflow kicks off. The first step is to execute a pre-defined, parameterized SQL query against BigQuery. This query enriches the new transaction with historical data (e.g., customer’s past order frequency, average order value, IP address history) and calculates a real-time fraud score based on our rule set.

  • Conditional Routing: Based on the fraud score returned by the query, the workflow branches. A low score might terminate the workflow. A medium score could log the event for later review. A high score, however, triggers the next critical step: alerting the human-in-the-loop.

Antigravity 2.0 provides the state management and resiliency needed to ensure that every transaction is evaluated reliably without us having to build complex state machines from scratch.

Communication Hub: Using the Google Chat API for alerts and commands

This is where the system becomes truly interactive. Instead of just sending an email or a plain text notification, we turn Google Chat into a command-and-control center. By leveraging the Google Chat API, we create a rich, two-way communication channel.

Outbound Alerts:

When the Antigravity workflow identifies a high-risk transaction, it doesn’t just send a message; it constructs a dynamic “Card” using the Chat API’s Card V2 format. This card is a mini-dashboard delivered directly to our fraud operations team’s Chat space, containing:

  • Key transaction details (Customer, Amount, Items).

  • The calculated fraud score and the specific rules that were triggered.

  • A set of interactive buttons: Approve Order, Block & Refund, and Investigate Further.

Inbound Commands:

Each button on the card is configured to send a callback to a secure endpoint (an HTTPS-triggered Cloud Function) when clicked. This function receives a payload identifying the user who clicked it, the transaction in question, and the action they chose. It then initiates the appropriate task in the execution layer, effectively allowing analysts to take decisive action directly from their chat client.

Execution Layer: Integrating with Shopify and Stripe APIs to take action

The final step is to translate the analyst’s decision into a concrete action in our source systems. This execution layer is a set of dedicated, single-purpose Cloud Functions that act as secure wrappers for third-party APIs.

When the command endpoint receives a callback from Google Chat, it invokes the relevant function:

  • Block & Refund: This action might trigger two separate functions. One calls the Shopify Admin API to cancel the specific order (POST /admin/api/2023-10/orders/{order_id}/cancel.json). The second function calls the Stripe API to create a full refund for the associated charge (POST /v1/refunds).

  • Approve Order: This could call a function that adds a fraud_review_approved tag to the order in Shopify, removing it from any automated holds and clearing it for fulfillment.

This layer is built with security and idempotency in mind. Each function is narrowly scoped with IAM permissions to perform only its specific task. It also handles the authentication and error-checking required to interact robustly with external platforms, ensuring that when an analyst clicks a button, the action is executed reliably and securely.

Implementation Guide From Anomaly to Action

With the architecture defined, let’s roll up our sleeves and build this thing. This guide breaks down the process into four distinct, manageable steps, taking you from raw data in BigQuery to a fully interactive auditor in Google Chat.

Step 1: Crafting anomaly detection queries in BigQuery

The brain of our operation is a BigQuery query. Its job is to sift through transaction data and flag activity that deviates from the norm. The definition of “anomaly” is unique to every business, but common patterns involve sudden high-value purchases, unusual geographic locations, or rapid-fire transactions.

Let’s create a query that identifies a classic fraud signal: a brand-new user making a large purchase from a high-risk country within the first hour of their account’s existence.

We’ll use Common Table Expressions (CTEs) to keep the logic clean and readable. Assume you have two tables: transactions and users.


-- This query identifies potentially fraudulent orders for review.

-- It flags orders that meet a specific set of high-risk criteria.

WITH recent_high_value_orders AS (

-- First, select recent orders over a certain threshold, e.g., $500.

SELECT

order_id,

user_id,

order_timestamp,

order_amount,

ip_country

FROM

`your-project-id.your_dataset.transactions`

WHERE

order_timestamp > TIMESTAMP_SUB(CURRENT_TIMESTAMP(), INTERVAL 15 MINUTE)

AND order_amount > 500.00

AND status = 'PENDING_REVIEW'

),

new_users AS (

-- Next, get the creation time for users associated with these orders.

SELECT

user_id,

account_creation_timestamp

FROM

`your-project-id.your_dataset.users`

WHERE

user_id IN (SELECT user_id FROM recent_high_value_orders)

),

high_risk_countries AS (

-- Define a list of countries you consider high-risk.

-- This could be a static list or another table.

SELECT 'DE' as country_code UNION ALL

SELECT 'VN' as country_code UNION ALL

SELECT 'RU' as country_code

)

-- Final SELECT statement to join the data and apply the logic.

SELECT

t.order_id,

t.user_id,

u.account_creation_timestamp,

t.order_timestamp,

t.order_amount,

t.ip_country

FROM

recent_high_value_orders AS t

JOIN

new_users AS u ON t.user_id = u.user_id

JOIN

high_risk_countries AS c ON t.ip_country = c.country_code

WHERE

-- The core logic: order placed within 60 minutes of account creation.

TIMESTAMP_DIFF(t.order_timestamp, u.account_creation_timestamp, MINUTE) < 60

This query is our starting point. You should tune the parameters—like the 15-minute lookback window, the $500 threshold, and the list of high-risk countries—to match your risk profile. The key is that the final output of this query is a list of anomalies, each one ready to become an alert.

Step 2: Configuring a secure Google Chat Space and webhook

Now we need a destination for our alerts. A Google Chat Space is the perfect venue for your fraud and security teams to collaborate. The connection between BigQuery’s findings and this Chat Space is an incoming webhook.

A webhook is a unique URL that allows external applications to post messages into a Chat Space securely. Think of it as a private mailing address for your automated system.

Here’s how to set it up:

  1. Create a new Google Chat Space:
  • In Google Chat, click the + sign next to “Spaces” and select “Create a Space”.

  • Give it a descriptive name, like “Fraud Alerts - Production”.

  • Add the relevant team members who will be responsible for reviewing the alerts.

  1. Add an incoming webhook:
  • Click the dropdown arrow next to your new Space’s name.

  • Select “Apps & Integrations”.

  • Click “Add webhooks”.

  • Provide a name for the webhook, like “BigQuery Anomaly Detector”. You can also add an optional avatar URL to make the alerts easily identifiable.

  • Click “Save”.

Chat will now generate a unique URL for your webhook.

CRITICAL: Treat this webhook URL as a secret. Anyone with this URL can post messages to your Space. Copy it and store it securely; we’ll need it in the next step, likely as a secret or environment variable in your execution environment.

Step 3: Streaming alerts as interactive Chat cards

Sending a plain text message is easy, but we can do much better. Google Chat supports richly formatted, interactive “cards” that can display information cleanly and provide users with actionable buttons.

To execute our BigQuery query and post the results, we’ll use a serverless setup: a Cloud Function triggered on a schedule by Cloud Scheduler.

  • Cloud Scheduler: A cron job that will trigger our Cloud Function every, say, 5 minutes.

  • Cloud Function: A small, event-driven piece of code (we’ll use JSON-to-Video Automated Rendering Engine) that runs the BigQuery query, formats each result into a Chat card, and sends it via the webhook.

Here is the Python code for a Cloud Function that accomplishes this.


import os

import json

import requests

from google.cloud import bigquery

# Best practice: Store the webhook URL as an environment variable.

CHAT_WEBHOOK_URL = os.environ.get('CHAT_WEBHOOK_URL')

GCP_PROJECT_ID = os.environ.get('GCP_PROJECT_ID')

def run_fraud_check(request):

"""

Cloud Function to run a BigQuery fraud detection query and post alerts to Google Chat.

"""

if not CHAT_WEBHOOK_URL or not GCP_PROJECT_ID:

print("Error: CHAT_WEBHOOK_URL or GCP_PROJECT_ID not set.")

return "Configuration error", 500

client = bigquery.Client(project=GCP_PROJECT_ID)

# Use the query from Step 1.

# For production, consider loading this from a .sql file.

query = """

WITH recent_high_value_orders AS (

SELECT order_id, user_id, order_timestamp, order_amount, ip_country

FROM `your-project-id.your_dataset.transactions`

WHERE order_timestamp > TIMESTAMP_SUB(CURRENT_TIMESTAMP(), INTERVAL 15 MINUTE)

AND order_amount > 500.00 AND status = 'PENDING_REVIEW'

),

new_users AS (

SELECT user_id, account_creation_timestamp FROM `your-project-id.your_dataset.users`

WHERE user_id IN (SELECT user_id FROM recent_high_value_orders)

),

high_risk_countries AS (

SELECT 'DE' as country_code UNION ALL SELECT 'VN' as country_code

)

SELECT t.order_id, t.user_id, u.account_creation_timestamp, t.order_timestamp,

t.order_amount, t.ip_country

FROM recent_high_value_orders AS t

JOIN new_users AS u ON t.user_id = u.user_id

JOIN high_risk_countries AS c ON t.ip_country = c.country_code

WHERE TIMESTAMP_DIFF(t.order_timestamp, u.account_creation_timestamp, MINUTE) < 60

"""

try:

query_job = client.query(query)

results = query_job.result()

for row in results:

card_payload = create_chat_card(row)

send_to_chat(card_payload)

return "Alerts processed successfully", 200

except Exception as e:

print(f"An error occurred: &#123;e&#125;")

return "Error processing alerts", 500

def create_chat_card(data):

"""Formats a BigQuery row into a Google Chat card JSON payload."""

order_id = data.get('order_id')

user_id = data.get('user_id')

card = {

"cardsV2": [{

"cardId": f"fraud-alert-&#123;order_id&#125;",

"card": {

"header": {

"title": "High-Risk Order Detected",

"subtitle": f"Order ID: &#123;order_id&#125;",

"imageUrl": "https://img.icons8.com/color/48/000000/error--v1.png",

"imageType": "CIRCLE"

},

"sections": [{

"header": "Anomaly Details",

"collapsible": False,

"widgets": [

{ "keyValue": { "topLabel": "Amount", "content": f"$&#123;data.get('order_amount'):.2f&#125;" } },

{ "keyValue": { "topLabel": "User ID", "content": str(user_id) } },

{ "keyValue": { "topLabel": "IP Country", "content": data.get('ip_country') } },

{ "keyValue": { "topLabel": "Order Time", "content": str(data.get('order_timestamp')) } },

{ "keyValue": { "topLabel": "Account Created", "content": str(data.get('account_creation_timestamp')) } }

]

}, {

"widgets": [{

"buttonList": {

"buttons": [

{

"text": "Investigate User",

"onClick": {

"action": {

"function": "investigate_order",

"parameters": [{"key": "orderId", "value": str(order_id)}, {"key": "userId", "value": str(user_id)}]

}

}

},

{

"text": "Block Order",

"color": { "red": 0.9, "green": 0.1, "blue": 0.1, "alpha": 1 },

"onClick": {

"action": {

"function": "block_order",

"parameters": [{"key": "orderId", "value": str(order_id)}]

}

}

}

]

}

}]

}]

}

}]

}

return card

def send_to_chat(payload):

"""Sends a JSON payload to the configured Google Chat webhook."""

headers = {'Content-Type': 'application/json; charset=UTF--8'}

try:

response = requests.post(CHAT_WEBHOOK_URL, data=json.dumps(payload), headers=headers)

response.raise_for_status()

print(f"Successfully sent message to Chat. Status: &#123;response.status_code&#125;")

except requests.exceptions.RequestException as e:

print(f"Error sending to Google Chat: &#123;e&#125;")

When an anomaly is found, this function constructs and sends a card that looks clean, presents all the critical data, and—most importantly—includes “Investigate User” and “Block Order” buttons. Clicking these buttons won’t do anything yet; that’s what we’ll build in the final step.

Step 4: Building conversational commands to investigate or block orders

Our system can now push alerts, but the real power comes from closing the loop—allowing analysts to take action directly from the Chat interface. To do this, we need to upgrade from a simple webhook to a full-fledged Google Chat App.

A Chat App can not only send messages but also receive events from Google Chat, like when a user clicks a button on a card.

Here’s the workflow:

  1. Configure a Chat App: In the Google Cloud Console, enable the “Google Chat API”. Under “Configuration”, you’ll set up your app. The most important setting is the App URL. This URL must point to a new, publicly accessible Cloud Function that will act as your command handler.

  2. Create the Command Handler Cloud Function: This function is the endpoint for all interactivity. When a user clicks a button on a card, Google Chat sends a detailed JSON payload (an event) to this function’s App URL.

  3. Process the Event: The function’s job is to parse the incoming event to determine which button was clicked and what data was associated with it (like the orderId).

Below is a Python skeleton for this second Cloud Function. It acts as a router, directing incoming actions to the appropriate logic.


import json

# In a real app, these functions would interact with your backend systems.

def handle_investigation(user_id, order_id):

"""Fetches more details about a user and returns a formatted message."""

# Example: Query your user database or CRM for more info.

user_history = f"User &#123;user_id&#125; has 3 previous orders. No chargebacks."

message = f"Investigation for Order `&#123;order_id&#125;`:\n&#123;user_history&#125;"

return {"text": message}

def handle_blocking(order_id):

"""Calls an internal API to block an order and returns a confirmation."""

# Example: Make an API call to your order management system.

# api.block_order(order_id)

message = f"✅ Order `&#123;order_id&#125;` has been flagged and blocked."

return {"text": message}

def command_handler(request):

"""

Cloud Function to handle interactive events from Google Chat cards.

"""

# Verify the request is from Google Chat (see Google's security docs).

# For simplicity, we'll skip that here, but it's critical for production.

event = request.get_json(silent=True)

if not event:

return {"text": "Invalid request format."}

try:

# The action's name is in 'action.function'.

action_name = event['action']['function']

# Parameters are passed as a list of key-value pairs.

params = {p['key']: p['value'] for p in event['action']['parameters']}

response_message = {}

if action_name == 'investigate_order':

user_id = params.get('userId')

order_id = params.get('orderId')

response_message = handle_investigation(user_id, order_id)

elif action_name == 'block_order':

order_id = params.get('orderId')

response_message = handle_blocking(order_id)

else:

response_message = {"text": f"Unknown action: &#123;action_name&#125;"}

# The function's return value is posted back to the Chat space.

# 'UPDATE_MESSAGE' replaces the card, 'NEW_MESSAGE' posts a new reply.

return json.dumps({"actionResponse": {"type": "NEW_MESSAGE"}, "body": response_message})

except (KeyError, TypeError) as e:

# Handle cases where the event payload is not as expected.

print(f"Error parsing event: &#123;e&#125;")

return json.dumps({"text": "Error processing your request."})

When this function is deployed and linked to your Chat App, the loop is complete. A BigQuery query detects an anomaly, a Cloud Function posts a card, an analyst clicks “Block Order”, and a second Cloud Function receives the command and executes the block action via an API call, posting a confirmation back to the thread. You’ve successfully transformed a passive data warehouse into an active, real-time auditing tool.

Measuring the Impact: ROI and Enhanced Security

Deploying a real-time fraud auditor is more than a technical achievement; it’s a strategic investment in the financial health and integrity of your platform. The true value materializes when we measure its impact on key business and security metrics. This system moves fraud detection from a reactive, forensic exercise to a proactive, real-time intervention, fundamentally altering your security posture and delivering a clear return on investment.

Dramatically reducing time-to-detection and response

The most immediate and profound impact of this architecture is the radical compression of the incident timeline. In traditional environments, fraud detection often relies on batch processes that run overnight or hourly. An analyst might only see a suspicious transaction in a report generated hours after the event, by which time the fraudster has vanished and the damage has multiplied.

This Google Chat-based system obliterates that delay. The time-to-detection (TTD)—the period between a fraudulent event occurring and your team becoming aware of it—is reduced from hours to mere seconds.

  • Event to Alert: As soon as a transaction is streamed into BigQuery, it’s analyzed against your fraud models. A trigger event fired by a Cloud Function or Cloud Run service is nearly instantaneous.

  • Alert to Analyst: The alert isn’t buried in an email inbox or a crowded dashboard. It’s a direct, actionable push notification in Google Chat, a tool your team already has open.

This immediacy directly translates to a minimized time-to-response (TTR). Analysts don’t need to hunt for information; the critical data is delivered to them. The decision-making interface (the interactive buttons) is embedded in the alert itself. This transforms the workflow from a multi-step, context-switching process into a single, fluid action. The entire cycle, from a fraudulent transaction hitting your system to an analyst blocking the malicious actor, can be completed in under a minute.

Minimizing financial losses from fraudulent transactions

Reducing detection time is not just a vanity metric; it has a direct and quantifiable correlation with minimizing financial loss. Fraudulent schemes, especially automated ones, are designed for volume and speed. A compromised account or stolen credit card isn’t used once—it’s used repeatedly until it’s shut down.

By shrinking the window of opportunity from hours to minutes, you are not just stopping a single fraudulent transaction; you are preventing the dozens that would have followed.

Consider a simple ROI calculation:

  1. Baseline (Before): A stolen card is used 30 times over a 4-hour period before being flagged by a batch report. If the average transaction value is $100, the total loss is $3,000.

  2. **Real-Time System (After): The first anomalous transaction triggers an immediate Google Chat alert. An analyst reviews and blocks the card within two minutes. The total loss is capped at the initial $100 transaction.

In this single incident, the system prevented $2,900 in direct losses. When you extrapolate this across hundreds or thousands of incidents per year, the financial justification becomes undeniable. The system pays for itself by turning your security team into a profit-protection center, actively preserving revenue that would have otherwise been lost to fraud.

Creating an immutable and meticulous audit trail for every decision

Beyond immediate financial gains, this architecture establishes an invaluable, long-term asset: a centralized and immutable audit trail. In many organizations, fraud review decisions are scattered across emails, siloed spreadsheets, or private messages, making it nearly impossible to reconstruct events for compliance audits or internal reviews.

Our system creates a complete, chronological record of every step, logged automatically in BigQuery:

  1. The Event: The original transaction data is stored in BigQuery, serving as the initial record.

  2. The Alert: The invocation of the Cloud Function and the payload sent to Google Chat are logged, proving an alert was generated and delivered.

  3. **The Decision: When an analyst clicks a button in Google Chat (“Block User,” “Approve Transaction”), the callback to your backend service is a discrete, loggable event. This captures who made the decision, what the decision was, and the precise timestamp.

  4. The Action: The backend service logs the subsequent API calls it made to enforce the decision (e.g., blocking the user’s account, refunding the charge).

  5. The Closure: A final record is written back to a dedicated audit table in BigQuery, linking the original transaction ID to the analyst, their decision, and the final outcome.

This meticulous chain of custody is critical for compliance with regulations like PCI-DSS and provides unimpeachable evidence for financial audits. Furthermore, this structured, labeled data—{transaction data, human decision}—becomes a high-quality training set for iterating on and improving your machine learning fraud models, creating a powerful feedback loop that makes your entire system smarter over time.

Conclusion: Fortify Your E-commerce Architecture

We’ve journeyed from a raw stream of transaction data in BigQuery to a sophisticated, real-time fraud detection and response system integrated directly into your team’s workflow. This isn’t just an academic exercise; it’s a blueprint for building a more resilient, responsive, and operationally intelligent e-commerce platform. By closing the loop between data insight and human action, you transform your architecture from a passive data repository into an active defense mechanism.

Recap: The power of a real-time, conversational triage system

The solution we’ve built demonstrates a paradigm shift away from traditional monitoring. Instead of relying on analysts to perpetually watch dashboards and manually cross-reference data, we’ve created an automated, event-driven system with distinct advantages:

  • Velocity: Alerts are triggered and delivered within seconds of a suspicious event being written to BigQuery. This immediacy is critical during high-volume periods like flash sales, where a fraudulent attack can escalate rapidly.

  • Context: Each Google Chat notification is a rich, self-contained incident report. It doesn’t just say “there’s a problem”; it presents the specific transaction IDs, user details, and risk scores, providing all the necessary context to make an informed decision.

  • Actionability: The integrated action buttons (Block User, Mark as Safe) are the most powerful feature. They transform a passive notification into an interactive triage console, drastically reducing the Mean Time To Resolution (MTTR) and empowering your team to mitigate threats directly from their communication hub.

By weaving together the analytical prowess of BigQuery, the serverless elasticity of Cloud Functions, and the collaborative interface of Google Chat, we’ve built a system that is greater than the sum of its parts.

Beyond flash sales: Applying this model to other business-critical events

The true architectural elegance of this pattern lies in its versatility. While we focused on fraud detection, the core components—real-time data analysis, serverless function triggers, and conversational UI—can be adapted to a wide array of business-critical scenarios. Consider these possibilities:

  • Inventory & Supply Chain: Trigger alerts when stock levels for a high-demand product fall below a critical threshold. Action buttons could allow a merchandising manager to “Initiate Rush Reorder” or “Allocate Warehouse Stock” instantly.

  • Infrastructure & Operations: Monitor for application performance anomalies, such as a sudden spike in API error rates (5xx) from a specific region. Actions could include “View Grafana Dashboard” or “Trigger PagerDuty Escalation.”

  • Customer Experience: Analyze customer support chat logs or reviews in real-time. If [How to build a Custom Sentiment Analysis System for Operations Feedback Using Google Forms OSD App Clinical Trial Management and [Building Self Correcting Agentic Workflows with Building Self-Correcting Agentic Workflows with Vertex AI](https://votuduc.com/building-self-correcting-agentic-workflows-with-vertex-ai-p-20260321542526)](https://votuduc.com/How-to-build-a-Custom-Sentiment-Analysis-System-for-Operations-Feedback-Using-Google-Forms-AppSheet-and-Vertex-AI-p428528) detects a severely negative experience, an alert can be sent to a support lead with options to “View Full Transcript” or “Assign to VIP Support.”

  • Security & Compliance: Detect anomalous login patterns, such as multiple failed login attempts followed by a success from a new geographic location. An alert to your SecOps channel could have actions like “Force MFA Re-authentication” or “Temporarily Suspend Account.”

The pattern remains the same: identify a critical business event in your data, define the analytical trigger in BigQuery, and build the corresponding serverless logic and conversational response.

Ready to scale your architecture? Book a GDE discovery call

Implementing a single real-time auditor is a powerful first step. Integrating this pattern across your entire operational landscape is a strategic advantage. If you’re looking to apply these concepts to more complex challenges—from orchestrating multi-stage remediation workflows to handling petabyte-scale data streams—specialized expertise can accelerate your journey.

Our team, led by Google Developer Experts in Cloud and Data Analytics, can help you design and implement robust, scalable, and secure architectures tailored to your unique business needs.

Book a complimentary discovery call with our GDE team to explore how you can transform your operations with real-time, event-driven systems on Google Cloud.


Tags

BigQueryGoogle ChatFraud DetectionReal-Time AnalyticsData EngineeringE-commerceAutomation

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Vo Tu Duc

Vo Tu Duc

A Google Developer Expert, Google Cloud Innovator

Stop Doing Manual Work. Scale with AI.

Hi, I'm Vo Tu Duc (Danny), a recognised Google Developer Expert (GDE). I architect custom AI agents and Google Workspace solutions that help businesses eliminate chaos and save thousands of hours.

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