What is the difference between a PaaS and an Internal Developer Platform?

## Introduction

The Platform Engineering space is growing rapidly. If you’re an engineering leader or a DevOps/Platform engineer trying to asses what tools to buy and what to build in-house, it only becomes more confusing when coming across various platforms that are labeled PaaS (Platform-as-a-service) and IDPs (Internal Developer Platforms). Many enterprise “experts” refer to PaaS as toys that cannot scale (proven wrong <source>). On the other hand, many startups look at IDPs as an over-engineered tool that satisfies the *Not Invented Here Syndrome*. The reality lies in the gray area, so let’s dive deeper to separate the purpose and role of each.

## What is a PaaS?

Platform as a Service, or PaaS, is a cloud-based platform that offers a suite of services to support the development, deployment, and management of applications. It's designed to simplify and streamline the process for developers, allowing them to focus more on building software rather than managing infrastructure. PaaS solutions, often built atop major cloud providers, handle the complexities of infrastructure with minimal user expertise required. Firebase, Heroku, Render, and Fly.io have become synonymous with ease of deployment and integration, especially with services like GitHub for automatic builds and deployments. Commit your code and the PaaS provider will build the code and deploy it with no downtime.

### Characteristics of a PaaS

- Tight integrations with GitHub, GitLab, etc. for auto-build/deploy
- Supports buildpacks and docker images
- Auto-scaling is automatically managed
- Many offer basic deployment pipelines as part of the offering
- Basic Logs/Telemetry is built in with limited integrations to other providers
- Infrastructure is managed by PaaS; no access to customize infrastructure
- Private Networking is usually available at a premium
- Limited to simple system architectures and no customization

## How is an IDP Different?

When software teams grow, they grow out of a PaaS. An Internal Developer Platform (IDP) is a common next step for many teams as they go beyond the scope of PaaS to provide a streamlined developer experience for teams using various tooling for software delivery, cloud infrastructure, and observability. It's an internal ecosystem of tools, templates, and best practices aimed at serving the entire software organization, including roles like software developers, data scientists, and SREs.

In some organizations, it may be enough to create a catalog of templates and rely on developers to build custom automation. This type of IDP is cheap, but usually requires significant onboarding, education, and maintenance to provide significant value. Organizations realize they can get enormous productivity gains by building an in-house IDP. With a dedicated platform team, these IDPs usually contain a UI portal and orchestration like a PaaS, but with their own tooling and workflows. The developer experience is tailored directly for their use case that meets internal governance, compliance constraints, and methods to meet customer needs.

### Characteristics of an IDP

- Open-source/inner-source catalog of infrastructure patterns
- Frequently contain a UI portal with a centralized dashboard
- Deployments centralized in orchestrator or done in custom automation via CI/CD tooling
- Logs/Telemetry configured by platform team for vendor chosen by organization
- Makes heavy use of major cloud providers and often Kubernetes
- Provides flexibility for complex architectures

## Should I use a PaaS or IDP?

Some have called IDPs PaaS-like and others have called PaaS IDP-like. This overlap in functionality makes it challenging for a team to determine what works best for their use case. Previously, IDPs were reserved for Enterprises due to the enormous investment of IDPs. However, commercial offerings have emerged to provide a cheaper alternative to in-house IDP builds.

Many teams start with a PaaS due to the generous free plans and ease-of-use to get started. Many believe that growing out of a PaaS means reaching a massive technical scale. However, most teams outgrow PaaS well before they reach technical scaling limitations. To assess which is best for your use case, let’s explore the reasons to switch from a PaaS to an IDP.

### Growing complexity with a need for DevOps

As software teams grow, they inevitably face the challenge of scaling their development and operational capabilities efficiently. This scaling often requires a robust DevOps approach to manage increasing complexity, maintain agility, and ensure consistent product quality. The number of repositories and apps grows along with the size and scope of production data.

Over time, a product naturally expands in the number of repositories and apps that are hosted to service customers. Whether intentional or not, many teams adopt microservices or service-oriented architecture. In these scenarios, PaaS offerings can’t handle the configurability and overhead incurred from a distributed architecture. Additionally, coordinating and orchestrating these dependencies across environments becomes  increasingly important to reduce the risk of errors.

As this architecture grows, the cost of managing additional vendors grows prompting a need for DevOps engineers to maintain these health and integrity. For example, each app needs to push the correct logs and metrics to one or many telemetry providers and roll-up those metrics into operational dashboards that the team can utilize to ensure uptime, reliability, security, and performance.

### Growing team with a need for collaboration

A growing team often means a need to coordinate shared resources and collaborate through internal workflows. Engineers need visibility into their internal ecosystem to effectively contribute. Whether during onboarding, moving in between teams, or rolling out a new feature, an IDP provides a broad view that enables engineers to make informed decisions and improve the system. Too often, teams discover issues late in the development cycle causing the team to stagnate in feature development while they resolve bugs and design issues.

Inevitably, a software team faces operational fires that need extinguished. Even with a proper observability system in place, it can be difficult to track down and correlate the source of app code and infra changes. While a PaaS offers tracking for an app, an IDP offers a centralized tracking of changes that simplifies root-cause analysis.

A growing team also means a diversification of skills and roles, necessitating a platform that can cater to varied technical needs and expertise levels. This can range from providing simplified workflows for new or less technical team members, to offering advanced customization and control for experienced developers and engineers.

The decision between a Platform as a Service (PaaS) and an Internal Developer Platform (IDP) becomes crucial here. While PaaS offers ease of use and quick setup, which is beneficial for smaller or less complex projects, it might lack the flexibility and control required for larger, more diverse teams. On the other hand, IDPs, while requiring more initial setup and investment, offer tailor-made solutions that can grow and adapt with the team, providing a more sustainable and efficient workflow in the long run.

### Need to use services by a major cloud provider

As software teams evolve and their needs become more complex, they often outgrow the proprietary services offered by Platform as a Service (PaaS) providers. Initially, PaaS solutions are attractive due to their ease of use, simplicity in deployment, and abstraction of underlying infrastructure complexities. However, as teams expand, the limitations of these proprietary services can become apparent, leading to a need for more advanced and diverse capabilities that are often available through major cloud providers like Amazon Web Services (AWS), Microsoft Azure, and Google Cloud Platform (GCP).

The transition from PaaS to using services offered by these cloud giants is primarily driven by the desire for greater control, flexibility, and the ability to customize and optimize the infrastructure to meet specific needs. Major cloud providers offer a wide array of advanced services, including sophisticated data analytics, machine learning, high-level storage solutions, and extensive networking capabilities that can be pivotal for a growing team’s requirements.

Teams may find that the one-size-fits-all approach of PaaS becomes a constraint. An IDP offers a similar developer experience as PaaS, but with the flexibility of using any service offered by major cloud providers.

### Serve an industry with compliance/security constraints

For software teams operating in industries with stringent compliance and security requirements, such as healthcare, finance, or government, the choice between a Platform as a Service (PaaS) and an Internal Developer Platform (IDP) is pivotal. These industries often have strict regulations governing data protection, privacy, and operational standards, which significantly influence the technological infrastructure and development processes.

PaaS solutions offer a certain level of built-in security and compliance features that can be appealing for teams looking for out-of-the-box solutions. Providers often ensure their platforms are up-to-date with the latest security protocols and may offer compliance certifications relevant to various industries. This can significantly reduce the burden on teams to maintain these aspects of their infrastructure. However, the challenge with PaaS lies in the limited control over the underlying infrastructure. For industries with highly specific compliance needs, the one-size-fits-all approach of PaaS might not suffice, especially when customization and detailed audit trails are required.

An IDP, in contrast, offers more flexibility and control, which is crucial for industries with specialized compliance and security needs. With an IDP, teams can tailor every aspect of the technology stack to meet specific regulatory requirements. This includes implementing custom security protocols, detailed logging and monitoring, and ensuring data handling processes comply with industry standards. An IDP also allows for greater agility in adapting to changes in regulatory landscapes, as internal teams can quickly modify their platforms to align with new requirements.

Furthermore, IDPs can integrate specific tools and services that are designed to address the unique challenges of regulated industries. This can include advanced encryption methods, more robust identity and access management solutions, and specialized data governance tools.

## Conclusion

In the dynamic field of Platform Engineering, choosing between Platform as a Service (PaaS) and Internal Developer Platforms (IDP) is a critical decision for engineering teams. PaaS offers ease of use and quick deployment, ideal for smaller teams and less complex projects. However, as teams grow and require greater control and customization, especially in compliance-heavy industries, IDPs become more relevant. IDPs provide tailor-made solutions and flexibility but demand more investment and expertise. Ultimately, the choice depends on the team's size, complexity, and specific industry needs, balancing ease of use and scalability against customization and control. This decision is pivotal in shaping an organization's development processes and its capability to innovate and grow efficiently.