Supper Club × Edge Functions and Deno with Eduardo Bouças of Netlify

Episode Summary

Executive Summary: The episode explores Netlify Edge Functions, what makes them different from traditional serverless functions, and why Netlify uses Deno at the edge. Eduardo Bocas explains edge middleware use cases, performance and geography benefits, deployment/versioning, Deno’s runtime trade-offs, package compatibility concerns, database implications, and how open web standards reduce lock-in.

Main Topics: Serverless functions vs. edge functions: The hosts revisit what serverless functions are and contrast them with edge functions, emphasizing that edge functions still auto-provision but run closer to users worldwide for lower latency. Netlify Edge Function middleware patterns: Eduardo explains that edge functions can intercept requests before they reach their destination and can also modify responses on the way back, enabling authorization, redirects, and content personalization. Why Deno powers Netlify edge functions: The discussion covers Deno as a secure, performant JavaScript/TypeScript runtime with fast startup characteristics and a web-standards-oriented API surface that makes it suitable for edge use. Runtime and package ecosystem trade-offs: The episode highlights that Deno is not drop-in compatible with Node packages, especially those relying on Node-specific APIs, and that Deno imports packages by URL rather than via npm. Databases in a serverless/edge world: The conversation examines connection-pooling issues with traditional databases and the emerging trend of serverless or multi-region database offerings that better complement edge compute. Open standards and avoiding lock-in: Eduardo describes Netlify’s shift away from a proprietary Deno-based beta product toward edge functions built on open web standards like Request and Response objects. Developer habits and industry outlook: In closing, Eduardo shares his setup, productivity tools, learning philosophy, and excitement about the future of edge computing and what developers will build with it.

Key Arguments: Serverless functions are useful for adding small pieces of backend behavior without provisioning or managing a server, and they integrate cleanly with frontend code and deployment workflows. Edge functions differ mainly by location and invocation model: they run on many distributed points of presence, reducing latency for users around the world. Edge functions can act as middleware, enabling request inspection, auth checks, redirects, cookie manipulation, and response rewriting before content reaches the client. Using Deno at the edge is attractive because the runtime is designed for performance and fast startup, which matters when functions must begin handling requests quickly. Node compatibility is a real limitation for Deno-based edge environments; packages that depend on Node APIs may not work without adaptation. Databases are a major constraint for edge architectures because a centralized database can erase latency gains, pushing the ecosystem toward multi-region and serverless database designs. Netlify intentionally built edge functions around open web standards to avoid creating another proprietary runtime and to improve portability across platforms. A likely future trend is ecosystem convergence around portable packages and adapters that work across browser, Node, Deno, workers, and edge platforms.

Data Points: Edge function location: Dozens of locations around the world - Eduardo explains that edge functions duplicate code across many regions so visitors are routed to the nearest location. Serverless function region example: US East 1 - Used as an example of a centralized regional deployment for traditional serverless functions. Hasura free trial start time: 30 seconds - Promotional claim for getting started quickly with Hasura. Hasura zero-cost standard tier coupon: TryHasura - Coupon code mentioned for the Hasura offer. Hasura coupon limit: First 100 people - The offer is limited to the first 100 users of the coupon code. WP Mail SMTP discount: 50% off - Promotional offer for WP Mail SMTP. Podcast archive size: Hundreds of episodes - Postlight podcast is described as having hundreds of episodes. Conversation timing for Deno experimentation: Well over a year ago - Eduardo says Netlify started experimenting with Deno for edge use before launch. Edge performance goal: Single-digit or low double-digit milliseconds - Eduardo describes the desired startup/serve time for edge execution.

Pivotal Quotes: "we're talking about duplicating that code to potentially dozens of locations around the world" — Eduardo Bocas: Explanation of how edge functions differ from regional serverless functions. "you have access to effectively programming your CDN" — Eduardo Bocas: Describing the power and responsibility of edge functions handling headers, cookies, and routing behavior. "we see Deno as a new open runtime for the web that is built entirely in the open and that is based entirely on open standards" — Eduardo Bocas: Reasoning behind choosing Deno and prioritizing portability over a proprietary runtime.

Implications: Edge computing is moving web apps toward lower-latency, more composable infrastructure, but success depends on runtime portability, standards, and databases that can live closer to users. Developers should expect more middleware-like control at the CDN layer and less lock-in over time.