Custom blocks are bespoke building units added to an email editor to represent your product’s unique content or workflows. Instead of relying only on generic text and image blocks, custom blocks can model things like product cards, account summaries, dynamic recommendations, or branded modules that match your design language.
Why Custom Blocks Matter for SaaS Products
Custom blocks increase consistency and reduce user error. They let customers assemble emails from safe components rather than editing fragile HTML. Many teams treat a custom block as a reusable content block so the same module appears across multiple templates and campaigns with consistent behavior. This makes QA easier and reduces the chance of broken layouts.
Designing Blocks That Stay Maintainable
Consider how blocks evolve. If you change a block schema, define migration rules so older templates still render. Also provide sensible defaults so new blocks look correct without requiring the user to configure every field. These details prevent block libraries from becoming brittle as your product grows.
Custom blocks should follow a clear internal contract: inputs, outputs, and constraints. If a block can be configured, define which settings are safe to expose and which should be locked. Align block spacing and typography with your email design system so emails feel cohesive even when different people build them. When a block contains sensitive content or legal text, apply content locking so the module cannot be accidentally changed.
Blocks and Components Work Together
In modern editor architectures, custom blocks often wrap custom components that your engineering team already uses in the product UI. Reusing the same component logic can speed development and improve consistency, but you still need to validate that the resulting email output is robust across clients.
Custom Blocks and Topol
Topol supports custom blocks so SaaS teams can expose safe, branded modules inside an embedded editor without building an entire editor from scratch. Learn more at Topol or sign up at Topol signup.