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World Congress 2026 Europe • Jul 10, 2026 • Session details

20 billion requests a week: Upgrading Twilio's API gateway at scale

Ainhoa Arruabarrena Ortiz , Mario Román Dono , Marius Obert

How do you safely upgrade a legacy API gateway handling 20 billion weekly requests? Discover Twilio's five-year modernization strategy that conquered extreme technical debt with zero major disruptions.

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#1 about 3 min

The origin of Twilio's API tech debt

Years of rapid exponential growth created an undocumented ingress infrastructure that struggled to scale reliably.

#2 about 3 min

Legacy infrastructure components and non-negotiable requirements

Replacing a sprawling fleet of instances and dual gateways required maintaining strict backwards compatibility for existing clients.

#3 about 3 min

Architecting a unified contract-driven API gateway

Adopting a single source of truth based on Open API specifications enabled a modular, Kubernetes-driven cellular architecture.

#4 about 5 min

Executing safe traffic routing using intermediate DNS

Weighted DNS records and infrastructure-as-code configurations allowed granular traffic splitting and immediate rollback capabilities during the transition.

#5 about 5 min

Real-world migration roadblocks and undocumented dependencies

Uncovering unexpected client dependencies like legacy non-SNI connections and specific JSON orderings complicated simple platform updates.

#6 about 3 min

Performance outcomes of regional routing and cellularity

Rebuilding the edge infrastructure yielded improved network latency, zero downtime deploys, and an elevated developer experience for internal product teams.

#7 about 3 min

Modernizing edge experiences for agentic AI architectures

The next phase focuses on transitioning legacy XML responses to idiomatic JSON interfaces to empower conversational AI integrations.

Matching moments

3:46 min

Managing technical debt while iterating on API infrastructure

Anto Anto · WWC 2024

2:11 min

Executing massive cloud network migrations while maintaining live systems

Dana Lawson Dana Lawson +1 · WWC Europe 2026

6:44 min

Designing a resilient API gateway architecture

Lars Hesel Christensen +1 · LIVE

3:00 min

Refactoring a complex legacy monolith into microservices

Andrew Holway · LIVE

5:12 min

Addressing runtime migration specifics and future open source framework ambitions

Max Fischer Max Fischer +1 · WWC Europe 2026

1:33 min

Understanding technical debt and legacy application risks

Shaaf Syed Shaaf Syed · WWC 2025

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