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Serverless vs. containers: Choosing the right path for application modernization

AUG 25 2024   -   8 MIN READ
Aug 29, 2025
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6 MIN READ
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Modernize your cloud. Maximize business impact.

When it comes to modernizing applications, two terms come into the picture: serverless and containers. Both promise agility, scalability, and cost savings, but they aren’t interchangeable. Think of them like choosing between ride-sharing and owning a car. One gives on-demand convenience without worrying about maintenance, while the other gives you full control and flexibility but requires more management. 

For SMB leaders, picking the right approach directly impacts how fast they can innovate, how resilient their systems are, and how much value they get from the cloud. That’s why understanding where serverless and containers shine and where they fall short is critical to making the right modernization decision.

This article explores how SMBs can navigate the choice between serverless and containers, weighing scalability, cost, and agility to find the right fit for their growth journey.

Key takeaways:

  • Align workloads: Serverless for event-driven, bursty tasks; containers for persistent, complex, or legacy apps.
  • Manage overhead: Serverless minimizes ops; containers provide control and consistency.
  • Optimize costs: Serverless suits spiky usage; containers fit continuous, predictable workloads.
  • Plan for growth: Serverless boosts agility; containers support hybrid and incremental modernization.
  • Utilize expertise: AWS partners like Cloudtech ensure precise, SMB-tailored modernization strategies.

What is the difference between serverless and containers?

What is the difference between serverless and containers?

Serverless computing, offered through services like AWS Lambda, eliminates the need to manage servers by running small, event-driven functions only when triggered. It automatically scales with demand, and businesses pay solely for execution time. For SMBs, serverless is ideal for lightweight, event-driven workloads such as APIs, chatbots, automation, or data pipelines, enabling lean IT teams to innovate without infrastructure overhead.

Containers, powered by Amazon ECS or Amazon EKS, bundle applications with all dependencies into portable units that run consistently across environments. While they require orchestration, containers offer greater control, flexibility, and compatibility with existing systems. For SMBs, they’re well-suited to modernizing monoliths, migrating legacy workloads, or running long-lived services with custom runtimes or persistent connections, delivering agility without demanding a full application rewrite.

Factor

Serverless

Containers

Deployment model

Runs functions in response to events, fully managed by AWS

Runs containerized apps in managed clusters (ECS/EKS)

Scalability

Auto-scales instantly with demand

Scales with orchestration, requires configuration

Cost model

Pay-per-execution, no idle costs

Pay for allocated compute, even if underutilized

Control & flexibility

Limited runtime and environment control

Full control over runtime, libraries, dependencies

Best fit for SMBs

Event-driven, lightweight apps, APIs, or unpredictable workloads

Legacy modernization, long-running apps, microservices with custom needs

need help with cloud or data challenges

5 key factors to consider when choosing between serverless and containers

5 key factors to consider when choosing between serverless and containers

Selecting between serverless and containers directly impacts cost, scalability, and long-term agility. Picking the wrong model can lead to wasted resources, higher operational complexity, or stalled innovation. For instance, trying to force a long-running, resource-heavy application into serverless could result in unpredictable costs and performance bottlenecks. Similarly, running simple, event-driven workloads on containers might burden lean IT teams with unnecessary infrastructure management. 

In short, the wrong decision can lock SMBs into a path that drains time, budget, and focus, resources that should instead fuel growth and innovation.

These are the five critical factors to weigh before making the decision:

1. Matching workloads to the right model

When deciding between serverless and containers, the nature of the workload plays a critical role. Each model is optimized for different usage patterns and technical requirements, and AWS offers mature services to support both approaches.

Serverless (AWS Lambda, API Gateway, EventBridge, DynamoDB Streams): Serverless is built for event-driven and bursty workloads where execution is short-lived and scales instantly based on demand.

Relevant features:

  • Scales automatically in response to triggers such as S3 uploads, API calls, or stream events.
  • Pricing is tied directly to execution time and allocated memory, making it cost-effective for spiky or unpredictable traffic.
  • Ideal for real-time data transformations, automation scripts, lightweight APIs, and asynchronous jobs.

Maximum execution duration per Lambda is 15 minutes, and workloads needing persistent connections, custom networking, or OS-level control are not well-suited.

Example: An e-commerce SMB handling unpredictable spikes during flash sales can use Lambda + API Gateway to scale checkout and order processing instantly without provisioning servers.

Containers (Amazon ECS, Amazon EKS, AWS Fargate): Containers shine in scenarios where applications need long-running processes, complex dependencies, or granular infrastructure control.

Relevant features:

  • Provide a consistent runtime across environments, ensuring portability for modernized and legacy workloads.
  • Support stateful services, persistent connections, and specialized runtimes not possible in Lambda.
  • Well-suited for monolithic applications being broken into microservices, API backends requiring consistent performance, or real-time services like chat/messaging apps.

Unlike serverless, containers allow fine-tuning of compute, networking, and scaling policies, giving SMBs more control over performance.

Example: A logistics SMB modernizing its shipment tracking system with continuous real-time updates can use Amazon ECS on Fargate to maintain persistent connections and predictable long-running processes.

2. Meeting growth and performance demands

As SMBs grow, applications must scale reliably to handle more users, data, and transactions without compromising performance. The right choice between serverless and containers depends on whether growth is unpredictable or steady, and AWS offers services that adapt to both scenarios.

Serverless (AWS Lambda, Amazon DynamoDB, Amazon API Gateway): Serverless is optimized for elastic, demand-driven growth, making it ideal for workloads that experience sudden or uneven traffic spikes.

Relevant features:

  • Scales automatically to handle thousands of concurrent executions without manual intervention.
  • DynamoDB provides millisecond response times at virtually unlimited scale, supporting unpredictable usage patterns.
  • No capacity planning required, as usage-based pricing means SMBs only pay for what they consume.

Best suited for flash sales, seasonal campaigns, or viral user activity where demand surges are short-lived but intense.

Example: A ticketing SMB can rely on Lambda + DynamoDB to instantly scale when thousands of users attempt to book during a major event release, avoiding downtime and overprovisioning costs.

Containers (Amazon ECS, Amazon EKS, AWS Fargate, Amazon Aurora): Containers are better suited for predictable, performance-intensive workloads that need continuous scale and stable throughput.

Relevant features:

  • Enable horizontal scaling (adding more containers) or vertical scaling (tuning compute resources per container) based on workload demand.
  • Amazon Aurora with ECS/EKS provides high throughput and low latency for relational data workloads.
  • Support granular performance tuning for CPU, memory, and network, ensuring consistent user experience.

Ideal for always-on services, large data processing pipelines, or SaaS platforms with predictable growth.

Example: A logistics SMB running a real-time shipment tracking platform can use ECS with Aurora to maintain consistent performance as the user base grows steadily year over year.

struggling with slow data pipeline

3. Time and effort to manage infrastructure

One of the most important considerations for SMBs is how much time and expertise they can dedicate to managing infrastructure. The choice between serverless and containers often comes down to how much control an organization wants versus how much operational burden it can handle.

Serverless (AWS Lambda, API Gateway, DynamoDB): Serverless abstracts away most of the infrastructure complexity, allowing lean IT teams to stay focused on building business features rather than maintaining environments.

Relevant features:

  • No servers to patch, scale, or monitor, since AWS manages the underlying infrastructure.
  • Automatic scaling and high availability are built-in, reducing operational overhead.
  • Simplifies DevOps pipelines since deployment often requires just code packaging and configuration.

Best suited for SMBs that want to move fast without heavy infrastructure investment.

Example: A fintech SMB building fraud-detection workflows can use Lambda + DynamoDB Streams to automate real-time checks without dedicating resources to server patching or scaling.

Containers (Amazon ECS, Amazon EKS, AWS Fargate): Containers, while more powerful, require a higher degree of management, particularly when orchestration, monitoring, and patching come into play.

Relevant features:

  • Provide full visibility and control of the application environment, including networking, runtime, and scaling strategies.
  • Require container orchestration (via ECS/EKS), CI/CD integration, and monitoring setup (e.g., CloudWatch, Prometheus).
  • Fargate reduces some of this overhead by managing servers, but teams still need to design scaling policies and container configurations.

Better for SMBs that want fine-grained control and have or plan to build in-house DevOps expertise.

Example: A SaaS SMB delivering a multi-tenant application can use EKS with Fargate to gain control over scaling policies and runtime environments, while still offloading node management to AWS.

4. Cost efficiency at different scales

The pricing model is often a deciding factor for SMBs choosing between serverless and containers. While both approaches can be cost-effective, their efficiency depends heavily on workload patterns and scale.

Serverless (AWS Lambda, EventBridge, API Gateway): Serverless pricing is usage-based, which means SMBs only pay for what they use, down to milliseconds of execution.

Relevant features:

  • No costs when functions are idle, making it ideal for sporadic or unpredictable workloads.
  • Pricing is tied directly to execution time, memory, and request count.
  • Eliminates the need to provision idle capacity, which helps SMBs control costs when demand is uncertain.

However, costs may scale quickly for long-running, high-volume applications due to execution limits and pricing per invocation.

Example: A marketing SMB running event-driven campaigns with bursts of API traffic can rely on Lambda + API Gateway to handle spikes cost-effectively without ongoing server costs.

Containers (Amazon ECS, Amazon EKS, AWS Fargate): Containers have a different cost profile, often becoming more efficient at steady or large scales.

Relevant features:

  • Costs are based on the compute and storage resources allocated, regardless of whether the containers are fully utilized.
  • More predictable for workloads with continuous or long-running demand.
  • With reserved or savings plans on EC2/Fargate, SMBs can optimize for predictable workloads and reduce long-term costs.

At smaller scales, containers may introduce unnecessary fixed costs compared to serverless.

Example: A media SMB running a video processing pipeline 24/7 can achieve lower costs with ECS on EC2 Reserved Instances, rather than paying for repeated Lambda executions.

5. Balancing current complexity with future plans

The right choice between serverless and containers often depends on how an SMB balances current application complexity with future modernization goals. Both models support growth, but the starting point and trajectory matter.

Serverless (AWS Lambda, Step Functions, DynamoDB, EventBridge): Serverless is best suited for greenfield projects or modular applications that can be designed around events and AWS-managed services.

Relevant features:

  • Enables faster time-to-market with minimal infrastructure overhead.
  • Best for building new digital products, APIs, or automation workflows.
  • Naturally aligns with event-driven architectures, making scaling and integration simpler.

Example: A fintech SMB launching a new mobile payments feature can adopt serverless to iterate quickly, integrate with third-party APIs, and scale on-demand without investing in new infrastructure.

Containers (Amazon ECS, Amazon EKS, AWS Fargate): Containers are a stronger fit for SMBs dealing with existing, complex, or legacy applications where a full rewrite to serverless isn’t practical.

Relevant features:

  • Allow modernization at a controlled pace, by containerizing monolithic apps and gradually moving toward microservices.
  • Provide flexibility for hybrid cloud or multi-cloud strategies.
  • Offer portability for future migrations without binding entirely to serverless abstractions.

Example: A healthcare SMB with a legacy patient management system can containerize the existing application using ECS on Fargate, enabling modernization in stages while planning long-term cloud-native adoption.

AWS bills too high

Choosing between serverless and containers isn’t just a technical decision, it’s a strategic one that shapes scalability, costs, and future innovation. That is why, working with an AWS expert is essential to  avoid costly missteps. 

How does Cloudtech help SMBs modernize applications with precision?

How does Cloudtech help SMBs modernize applications with precision?

Cloudtech helps SMBs modernize applications with strategies tailored to each workload and business goal. Its team of former AWS professionals depend on their deep cloud-native expertise to transform legacy systems into scalable, resilient, and cost-efficient architectures. 

From breaking monoliths into microservices to adopting serverless or container-based designs, Cloudtech ensures modernization aligns with growth, performance, and operational efficiency, delivering future-ready applications without unnecessary complexity or spend.

Key Cloudtech services for application modernization:

  • Application assessment and modernization strategy: Cloudtech evaluates legacy applications to identify performance bottlenecks, scalability gaps, and integration challenges, then recommends modernization paths aligned with SMB business goals.
  • Serverless architecture implementation: Using AWS Lambda, API Gateway, and Step Functions, Cloudtech transforms suitable workloads into event-driven functions that scale automatically, reduce operational overhead, and improve cost efficiency.
  • Containerization and orchestration: Using Amazon ECS, EKS, and Fargate, Cloudtech helps SMBs migrate workloads into containerized environments, enabling microservices adoption, consistent runtime across environments, and support for long-running or stateful processes.
  • Operational automation and CI/CD: Cloudtech builds automated pipelines with AWS CodePipeline, CodeBuild, and CodeDeploy, accelerating release cycles, minimizing errors, and ensuring applications are deployed consistently and reliably.
  • Performance optimization and monitoring: Cloudtech continuously tunes compute, storage, and database configurations, and implements monitoring with Amazon CloudWatch, X-Ray, and Application Insights, ensuring applications run efficiently, cost-effectively, and remain highly available.

Through these capabilities, SMBs gain an AWS-architected, SMB-tailored modernization strategy. Cloudtech ensures applications are optimized for performance, scalability, and cost efficiency, while automating operational workflows, giving SMBs the confidence to innovate and grow without infrastructure bottlenecks.

See how other SMBs have modernized, scaled, and thrived with Cloudtech’s support →

want fast, clear data insights without the hassle

Wrapping up

Half-measures in modernization can leave SMB applications slow, costly, or hard to scale, undermining business agility. Choosing the right modernization path and following AWS best practices is no longer optional, it’s essential for resilient, future-ready operations.

With Cloudtech, SMBs can modernize applications with precision. Its team designs SMB-focused modernization strategies, optimizes workloads for performance and cost, automates operational workflows, and ensures applications scale seamlessly. The result is a cloud environment that drives innovation, supports growth, and eliminates infrastructure bottlenecks.

Connect with Cloudtech today to transform your applications into agile, scalable, and efficient assets that grow with your business.

FAQs

1. Can SMBs mix serverless and containerized architectures in a single application?

Yes. Many SMBs adopt a hybrid approach, using serverless for event-driven components (like API triggers or data processing) and containers for persistent or legacy services. AWS supports seamless integration via services like AWS Lambda invoking ECS tasks or sharing data through Amazon S3 and DynamoDB, enabling the best of both worlds.

2. How do deployment and scaling differ between serverless and containers?

Serverless automatically scales functions in response to triggers, requiring minimal management, while containers rely on orchestration tools like Amazon ECS or EKS to scale based on predefined metrics. SMBs need to evaluate how much operational overhead they can manage versus the flexibility and control containers provide.

3. Are there specific cost considerations SMBs should be aware of?

Serverless is cost-efficient for spiky or unpredictable workloads since billing is per execution, but it can become expensive for long-running or high-throughput tasks. Containers may have higher baseline costs due to always-on compute, but they offer predictable, optimized pricing for continuous workloads. Choosing the wrong model can inflate costs unnecessarily.

4. How does modernization affect existing legacy applications?

Serverless often requires refactoring or breaking down applications into microservices, which may not suit tightly coupled legacy systems. Containers allow SMBs to modernize incrementally, running legacy workloads with minimal changes while gradually adopting cloud-native practices for new components.

5. What tools can SMBs use to monitor and optimize their modernized applications?

AWS provides CloudWatch, X-Ray, and Application Insights for observability across both serverless and containerized workloads. These tools help SMBs track performance, detect bottlenecks, and optimize costs while ensuring applications meet uptime and scalability requirements.

With AWS, we’ve reduced our root cause analysis time by 80%, allowing us to focus on building better features instead of being bogged down by system failures.
Ashtutosh Yadav
Ashtutosh Yadav
Sr. Data Architect

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