The Challenge: Poor Send Time Optimization

Most marketing teams still send campaigns in broad waves: one global send, maybe a few time zones, and hope for the best. The reality is that every customer checks email, apps, and social feeds at different times. When you ignore this, even your best campaigns arrive when people are asleep, in meetings, or simply not in a discovery mindset.

Traditional approaches like fixed send windows, basic time-zone grouping, or manual A/B testing can no longer keep up. They treat audiences as blocks instead of individuals and rely on historical averages rather than real-time behavior. With fragmented channels and always-on journeys, static rules fail to capture patterns like “weekend-only openers”, “commuters checking mobile at 7:30”, or “night owls who only scroll after 22:00”.

The business impact is clear: lower open and click-through rates, higher unsubscribe risk, and wasted media and creative budgets. Messages get buried under more timely competitors, retargeting windows are missed, and carefully crafted personalization never gets a chance to perform because it arrives at the wrong moment. Over time, this erodes channel revenue, customer satisfaction, and trust in your marketing analytics.

The good news: poor send time optimization is very solvable. With modern AI, you can learn the unique engagement rhythm of each user and orchestrate sends accordingly across email, push, and in-app. At Reruption, we’ve helped teams move from static rules to AI-first workflows, turning raw engagement logs into practical decision engines. Below, you’ll find a concrete, marketing-friendly path to using Gemini to fix send time optimization and unlock the performance your campaigns actually deserve.

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Our Assessment

A strategic assessment of the challenge and high-level tips how to tackle it.

From Reruption’s experience building AI-first marketing workflows, poor send time optimization is usually not a creativity problem – it is a data and orchestration problem. Gemini gives marketing and data teams a practical way to turn raw engagement logs into per-user send time predictions, prototype models quickly, and then embed those predictions into your ESP or CDP without waiting for a multi-year martech overhaul.

Start with a Clear Send-Time Strategy, Not Just a Model

Before touching any Gemini API, define what “good send time optimization” means for your business. Are you optimizing for opens, downstream revenue, or a balance between performance and operational constraints (e.g. not sending SMS at night)? Agree on target metrics, key channels (email, push, in-app), and guardrails like quiet hours or regulatory restrictions.

This strategy acts as the decision layer above the model. It prevents teams from overfitting to open rates while ignoring brand impact or customer experience. Having a documented send-time strategy also makes it easier to align marketing, CRM, and data teams on what the Gemini models are supposed to deliver.

Treat Send Time Optimization as an Ongoing Product, Not a One-Off Project

Effective AI-powered send time optimization is never “done”. Customer habits shift with seasons, promotions, and even macro trends. If you treat the first Gemini model as a final deliverable, it will quickly become stale and underperform.

Instead, treat it as a product with a backlog: model improvements, new signals (e.g. app usage, web visits), and experiment ideas. Define a small responsible squad (marketing operations, data science/engineering, and a product owner) and give them ownership for the send-time optimization roadmap and KPIs. This mindset unlocks continuous performance gains instead of a one-time lift.

Design for Collaboration Between Marketers and Data Teams

Many send-time initiatives fail because marketers can’t access or interpret the models, and data teams don’t fully understand campaign constraints. With Gemini, you can bridge this gap by using it to generate SQL, explain model logic in plain language, and prototype experiments together in shared workspaces.

Strategically, set up recurring working sessions where marketing defines hypotheses (e.g. “weekday morning is best only for B2B buyers”) and data teams use Gemini to validate or refute them on historical data. This creates a shared understanding of what the model is actually doing and builds trust in the predictions when they hit the ESP/CDP.

Mitigate Risk with Guardrails and Incremental Rollouts

Jumping directly from a global send to a fully personalized schedule for all users introduces delivery and brand risks. Strategically, you want risk-mitigated AI adoption: start small, define guardrails, then scale with evidence. With Gemini, you can simulate predictions offline and compare against your current baseline before touching production traffic.

Roll out in phases: first for a single campaign type (e.g. newsletters), then for specific segments (e.g. high-intent users), and only later for transactional or critical messages. Set explicit performance thresholds – for example, “only scale if open rate improves by at least 8% with no increase in unsubscribe rate”. This makes the change defensible towards leadership and compliance.

Plan Early for Integration into ESPs and CDPs

AI for send time optimization only creates value when predictions actually drive sends. Strategically, you need a roadmap for how Gemini-generated send-time scores will flow into your ESP or CDP. That means clarifying which system is the source of truth for customer profiles and which tool orchestrates delivery.

Involve marketing ops and engineering early to map out data flows: from raw engagement logs, through Gemini-based modeling, into a prediction store, and finally into the orchestration layer. Having this architecture on paper avoids the common trap of building an impressive model that never leaves a notebook.

Using Gemini for send time optimization is less about fancy algorithms and more about building a focused, integrated decision engine that actually controls when messages are sent. When strategy, collaboration, guardrails, and integration are aligned, you can systematically lift engagement while improving customer experience. Reruption’s Co-Preneur approach and AI PoC work are designed exactly for this kind of challenge: we enter your stack, co-own the KPIs, and build the Gemini-powered workflows that make poor send times a thing of the past. If you’re serious about fixing this, a short conversation is often enough to outline a concrete, low-risk path forward.

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Real-World Case Studies

From Financial Services to Retail: Learn how companies successfully use Gemini.

Royal Bank of Canada (RBC)

Financial Services

In the competitive retail banking sector, RBC customers faced significant hurdles in managing personal finances. Many struggled to identify excess cash for savings or investments, adhere to budgets, and anticipate cash flow fluctuations. Traditional banking apps offered limited visibility into spending patterns, leading to suboptimal financial decisions and low engagement with digital tools. This lack of personalization resulted in customers feeling overwhelmed, with surveys indicating low confidence in saving and budgeting habits. RBC recognized that generic advice failed to address individual needs, exacerbating issues like overspending and missed savings opportunities. As digital banking adoption grew, the bank needed an innovative solution to transform raw transaction data into actionable, personalized insights to drive customer loyalty and retention.

Lösung

RBC introduced NOMI, an AI-driven digital assistant integrated into its mobile app, powered by machine learning algorithms from Personetics' Engage platform. NOMI analyzes transaction histories, spending categories, and account balances in real-time to generate personalized recommendations, such as automatic transfers to savings accounts, dynamic budgeting adjustments, and predictive cash flow forecasts. The solution employs predictive analytics to detect surplus funds and suggest investments, while proactive alerts remind users of upcoming bills or spending trends. This seamless integration fosters a conversational banking experience, enhancing user trust and engagement without requiring manual input.

Ergebnisse

  • Doubled mobile app engagement rates
  • Increased savings transfers by over 30%
  • Boosted daily active users by 50%
  • Improved customer satisfaction scores by 25%
  • $700M+ projected enterprise value from AI by 2027
  • Higher budgeting adherence leading to 20% better financial habits
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PayPal

Fintech

PayPal processes millions of transactions hourly, facing rapidly evolving fraud tactics from cybercriminals using sophisticated methods like account takeovers, synthetic identities, and real-time attacks. Traditional rules-based systems struggle with false positives and fail to adapt quickly, leading to financial losses exceeding billions annually and eroding customer trust if legitimate payments are blocked . The scale amplifies challenges: with 10+ million transactions per hour, detecting anomalies in real-time requires analyzing hundreds of behavioral, device, and contextual signals without disrupting user experience. Evolving threats like AI-generated fraud demand continuous model retraining, while regulatory compliance adds complexity to balancing security and speed .

Lösung

PayPal implemented deep learning models for anomaly and fraud detection, leveraging machine learning to score transactions in milliseconds by processing over 500 signals including user behavior, IP geolocation, device fingerprinting, and transaction velocity. Models use supervised and unsupervised learning for pattern recognition and outlier detection, continuously retrained on fresh data to counter new fraud vectors . Integration with H2O.ai's Driverless AI accelerated model development, enabling automated feature engineering and deployment. This hybrid AI approach combines deep neural networks for complex pattern learning with ensemble methods, reducing manual intervention and improving adaptability . Real-time inference blocks high-risk payments pre-authorization, while low-risk ones proceed seamlessly .

Ergebnisse

  • 10% improvement in fraud detection accuracy on AI hardware
  • $500M fraudulent transactions blocked per quarter (~$2B annually)
  • AUROC score of 0.94 in fraud models (H2O.ai implementation)
  • 50% reduction in manual review queue
  • Processes 10M+ transactions per hour with <0.4ms latency
  • <0.32% fraud rate on $1.5T+ processed volume
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American Eagle Outfitters

Apparel Retail

In the competitive apparel retail landscape, American Eagle Outfitters faced significant hurdles in fitting rooms, where customers crave styling advice, accurate sizing, and complementary item suggestions without waiting for overtaxed associates . Peak-hour staff shortages often resulted in frustrated shoppers abandoning carts, low try-on rates, and missed conversion opportunities, as traditional in-store experiences lagged behind personalized e-commerce . Early efforts like beacon technology in 2014 doubled fitting room entry odds but lacked depth in real-time personalization . Compounding this, data silos between online and offline hindered unified customer insights, making it tough to match items to individual style preferences, body types, or even skin tones dynamically. American Eagle needed a scalable solution to boost engagement and loyalty in flagship stores while experimenting with AI for broader impact .

Lösung

American Eagle partnered with Aila Technologies to deploy interactive fitting room kiosks powered by computer vision and machine learning, rolled out in 2019 at flagship locations in Boston, Las Vegas, and San Francisco . Customers scan garments via iOS devices, triggering CV algorithms to identify items and ML models—trained on purchase history and Google Cloud data—to suggest optimal sizes, colors, and outfit complements tailored to inferred style and preferences . Integrated with Google Cloud's ML capabilities, the system enables real-time recommendations, associate alerts for assistance, and seamless inventory checks, evolving from beacon lures to a full smart assistant . This experimental approach, championed by CMO Craig Brommers, fosters an AI culture for personalization at scale .

Ergebnisse

  • Double-digit conversion gains from AI personalization
  • 11% comparable sales growth for Aerie brand Q3 2025
  • 4% overall comparable sales increase Q3 2025
  • 29% EPS growth to $0.53 Q3 2025
  • Doubled fitting room try-on odds via early tech
  • Record Q3 revenue of $1.36B
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DBS Bank

Banking

DBS Bank, Southeast Asia's leading financial institution, grappled with scaling AI from experiments to production amid surging fraud threats, demands for hyper-personalized customer experiences, and operational inefficiencies in service support. Traditional fraud detection systems struggled to process up to 15,000 data points per customer in real-time, leading to missed threats and suboptimal risk scoring. Personalization efforts were hampered by siloed data and lack of scalable algorithms for millions of users across diverse markets. Additionally, customer service teams faced overwhelming query volumes, with manual processes slowing response times and increasing costs. Regulatory pressures in banking demanded responsible AI governance, while talent shortages and integration challenges hindered enterprise-wide adoption. DBS needed a robust framework to overcome data quality issues, model drift, and ethical concerns in generative AI deployment, ensuring trust and compliance in a competitive Southeast Asian landscape.

Lösung

DBS launched an enterprise-wide AI program with over 20 use cases, leveraging machine learning for advanced fraud risk models and personalization, complemented by generative AI for an internal support assistant. Fraud models integrated vast datasets for real-time anomaly detection, while personalization algorithms delivered hyper-targeted nudges and investment ideas via the digibank app. A human-AI synergy approach empowered service teams with a GenAI assistant handling routine queries, drawing from internal knowledge bases. DBS emphasized responsible AI through governance frameworks, upskilling 40,000+ employees, and phased rollout starting with pilots in 2021, scaling production by 2024. Partnerships with tech leaders and Harvard-backed strategy ensured ethical scaling across fraud, personalization, and operations.

Ergebnisse

  • 17% increase in savings from prevented fraud attempts
  • Over 100 customized algorithms for customer analyses
  • 250,000 monthly queries processed efficiently by GenAI assistant
  • 20+ enterprise-wide AI use cases deployed
  • Analyzes up to 15,000 data points per customer for fraud
  • Boosted productivity by 20% via AI adoption (CEO statement)
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FedEx

Logistics

FedEx faced suboptimal truck routing challenges in its vast logistics network, where static planning led to excess mileage, inflated fuel costs, and higher labor expenses . Handling millions of packages daily across complex routes, traditional methods struggled with real-time variables like traffic, weather disruptions, and fluctuating demand, resulting in inefficient vehicle utilization and delayed deliveries . These inefficiencies not only drove up operational costs but also increased carbon emissions and undermined customer satisfaction in a highly competitive shipping industry. Scaling solutions for dynamic optimization across thousands of trucks required advanced computational approaches beyond conventional heuristics .

Lösung

Machine learning models integrated with heuristic optimization algorithms formed the core of FedEx's AI-driven route planning system, enabling dynamic route adjustments based on real-time data feeds including traffic, weather, and package volumes . The system employs deep learning for predictive analytics alongside heuristics like genetic algorithms to solve the vehicle routing problem (VRP) efficiently, balancing loads and minimizing empty miles . Implemented as part of FedEx's broader AI supply chain transformation, the solution dynamically reoptimizes routes throughout the day, incorporating sense-and-respond capabilities to adapt to disruptions and enhance overall network efficiency .

Ergebnisse

  • 700,000 excess miles eliminated daily from truck routes
  • Multi-million dollar annual savings in fuel and labor costs
  • Improved delivery time estimate accuracy via ML models
  • Enhanced operational efficiency reducing costs industry-wide
  • Boosted on-time performance through real-time optimizations
  • Significant reduction in carbon footprint from mileage savings
Read case study →

Best Practices

Successful implementations follow proven patterns. Have a look at our tactical advice to get started.

Map and Prepare Your Engagement Data for Gemini

Effective send time optimization with Gemini starts with clean, well-structured engagement data. Begin by mapping where events live today: email sends, opens, clicks, push notifications, app sessions, and web visits. Standardize timestamps to a single time zone (e.g. UTC) and make sure you capture the user identifier, channel, and event type for each log entry.

Create a simplified engagement table that Gemini can work with, for example:

user_id | channel   | event_type | event_timestamp       | campaign_id
123     | email     | open       | 2025-10-11 07:31:02   | spring_newsletter
123     | web       | pageview   | 2025-10-11 07:35:10   | /product/123
...

Use Gemini to help you generate SQL that aggregates this data into per-user, per-hour engagement features (e.g. open counts by hour-of-day, day-of-week). This becomes the input for your send-time modeling.

Use Gemini to Prototype a Simple Per-User Send-Time Score

Instead of jumping directly into a complex model, start with a simple heuristic-based score that Gemini can help you design and validate. For each user, calculate their “preferred hour” based on historical engagement patterns.

You can use Gemini in a notebook or Workspace environment to draft and refine the logic:

Prompt to Gemini (for data teams):
"""
You are a data assistant. I have a table `user_email_events` with:
- user_id
- event_type (send, open, click)
- event_timestamp (UTC)

Write SQL that, for each user_id, calculates:
- total opens by hour of day (0-23)
- the hour with the highest open count (preferred_hour)
- a confidence score based on how dominant that hour is vs. others

Return a view `user_send_time_preferences` with:
user_id, preferred_hour, confidence_score
"""

Review the generated SQL with your data team, run it on a subset, and inspect the output. This gives you a baseline model that can already be pushed into your ESP/CDP as a custom field.

Generate and Operationalize Feature Engineering with Gemini

To move beyond naive heuristics, you need richer features: recency, frequency, weekday/weekend patterns, mobile vs desktop behavior, and cross-channel engagement. Gemini can speed up feature ideation and coding by translating natural language ideas into SQL or Python.

Prompt to Gemini:
"""
I want to engineer features for a send-time optimization model.
Given a table of email events (send, open, click) with timestamps, propose
10 useful features at user_id & channel level and write Python (pandas)
code to calculate them.

Consider:
- day of week patterns
- hour of day patterns
- recency of last open
- engagement intensity segments

Return only code and short comments.
"""

Use the generated code as a starting point in your pipeline. Store the resulting features in a feature table that both Gemini and your production systems can access, so you don’t duplicate work later.

Connect Gemini Predictions to Your ESP/CDP for Orchestrated Sends

Once you have per-user send-time scores or model predictions, the next step is connecting them to your ESP/CDP. Create or reuse custom fields such as best_send_hour, best_send_dow, and send_time_confidence in your customer profiles.

Use Gemini to help design the orchestration logic, then translate it into ESP/CDP workflows. For example:

Prompt to Gemini (for marketing ops):
"""
I have the following fields in my CDP:
- best_send_hour (0-23, in user's local time)
- best_send_dow (1-7)
- send_time_confidence (0-1)

We use ESP X, which supports scheduled sends and segments.
Draft a step-by-step configuration plan to:
1) Create segments based on confidence score
2) Schedule batch sends respecting best_send_hour and best_send_dow
3) Fallback to a global send time when confidence < 0.3

Explain each step clearly so a marketing ops manager can implement it.
"""

Implement the suggested steps in your tools, test with a small campaign, and validate that the ESP/CDP actually sends at the predicted times.

Set Up Continuous A/B Tests and Monitoring with Gemini Assistance

To prove value and keep improving, run controlled experiments. Randomly split your audience: one group uses AI-optimized send times, the other keeps the current schedule. Track open rate, click rate, conversion rate, unsubscribe rate, and delivery metrics.

Gemini can help you design the experiment and analyze results:

Prompt to Gemini:
"""
We ran an A/B test on email send times:
- Group A: global send at 10:00 local time
- Group B: AI-optimized send times using `best_send_hour`

Here are the metrics for each group (in CSV):
[PASTE METRICS]

1) Check if improvements are statistically significant
2) Summarize the results in non-technical language for executives
3) Recommend next steps for scaling or iterating the model
"""

Use the analysis to refine your targeting rules, adjust model thresholds, and build a performance report that justifies scaling the approach across more journeys and channels.

Build Marketing-Friendly Documentation and Playbooks with Gemini

Adoption often fails because marketers don’t understand how send-time decisions are made. Use Gemini to turn technical documentation into clear, role-specific playbooks: how send-time fields work, when they are updated, and how to use them in campaigns.

Prompt to Gemini:
"""
Here is a technical description of our send-time optimization pipeline:
[PASTE TECH DOC]

Rewrite this into a 2-page internal guide for campaign managers:
- Plain language, no math
- Explain what best_send_hour and best_send_dow mean
- How and when to use them in email and push campaigns
- Common pitfalls and FAQ
"""

Store these guides in your internal wiki and link them directly from your ESP/CDP so campaign owners can self-serve instead of opening tickets.

Implemented step by step, these best practices typically deliver realistic gains such as +5–15% email open rates, +5–10% click rates, and modest but meaningful improvements in downstream conversions. The exact uplift depends on your baseline and data quality, but with a structured Gemini-powered approach, you can expect visible improvements within a few campaign cycles rather than quarters.

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Frequently Asked Questions

Gemini lets you move from coarse, segment-level rules to per-user send time predictions. Instead of assuming “everyone in CET should get emails at 10:00”, Gemini can analyze historical engagement logs (opens, clicks, app sessions) to infer each user’s preferred hours and days for interaction.

Practically, this means your ESP/CDP receives fields like best_send_hour and best_send_dow for each user, which then drive scheduling logic. Over time, the model can learn patterns that simple rules miss, such as users who only engage on weekends or during evening hours, leading to higher open and click rates.

You’ll get the most value from Gemini if you can combine marketing operations, data engineering/analytics, and basic cloud skills. Someone needs to access engagement logs, prepare them for modeling, and set up a small pipeline that feeds predictions into your ESP/CDP.

The good news is that Gemini reduces the heavy lifting: it can generate SQL and Python for feature engineering, help design experiments, and translate technical logic into plain language for marketers. Many teams start with 1–2 data people (analyst/engineer) and a marketing ops specialist, then grow from there as the impact becomes clear.

For most organizations with existing engagement data, you can see first results within a few weeks. A typical phased approach looks like this:

  • Week 1–2: Data extraction, cleaning, and basic heuristic model (preferred hour/day).
  • Week 3–4: Integration of predictions into ESP/CDP and first A/B test on a single campaign type.
  • Week 5–8: Model refinement, broader rollout across more segments and channels, and performance reporting.

Because Gemini accelerates data exploration and code generation, the early stages (data prep and baseline modeling) are usually much faster than traditional projects, which is where most delays typically occur.

ROI depends on your baseline performance, list size, and campaign volume, but send time optimization is usually a high-leverage improvement. Many teams see 5–15% lifts in open rates and 5–10% in click rates when moving from global sends to personalized timing, especially if their current setup is very basic.

Because the underlying content and audience stay the same, any uplift is essentially “free leverage” on your existing budget. The main costs are initial setup and some ongoing maintenance. Gemini helps reduce both by automating analysis, code generation, and documentation – which shortens time-to-value and lowers the internal effort required to keep the models useful.

Reruption works with a Co-Preneur approach: we embed with your team like co-founders, not distant consultants. For send time optimization, that usually starts with our AI PoC offering (9,900€), where we validate – in a working prototype – that Gemini can use your real engagement data to generate actionable send-time predictions.

From there, we help you design the data pipeline, integrate predictions into your ESP/CDP, and set up the experiments and dashboards that prove business impact. Because we focus on AI engineering and enablement, we don’t just leave you with slides – we build the actual workflows, document them, and upskill your team so you own the solution. If you want to move from “we should personalize send times” to a live Gemini-powered system in weeks, not months, this is exactly the kind of project we like to co-own.

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