How teams scaled Redis: 5 real case studies
5 of the 94 engineering write-ups in our database mention Redis in their stack. They come from 5 companies (Figma, OpenAI, Shopify, Stack Overflow and Stripe) and were published between 2016 and 2026. 3 of the 5 state concrete scale numbers, for example "tens of thousands of sandboxes across products" (Figma). Each card below links to our short summary and the original post.
Not every story keeps Redis: Shopify moved checkout inventory reservations to MySQL and it scaled.
How Figma manages sandboxes at scale
Figma's AI products needed secure places to run untrusted code, so the team built Nimbus, a centralized sandbox platform that product teams call through a simple namespace config and GetOrCreate/Get/Delete APIs. Nimbus picks a cloud provider, applies networking and security policies (trusted-host allowlists plus read-only GET/HEAD/OPTIONS to the rest of the internet, credentials decrypted only on the way out to their intended destination), and runs sandboxd inside each box for process supervision and metrics. Warm pools of already-running sandboxes cut provisioning latency by about 90% versus cold starts, raised availability from 99% to 99.95%, and absorb minutes of provider outages while Postgres claim transactions and a Redis health-check queue keep the pool correctly sized and singly assigned.
We replaced Redis with MySQL for inventory reservations—and it scaled
Shopify moved checkout inventory reservations from Redis to MySQL using one row per sellable unit, a bounded pool of 1,000 rows per item/location and SELECT ... FOR UPDATE SKIP LOCKED. The real ceiling was connections held by other checkout code: tagging SQL by business process and measuring hold time in ProxySQL found it, and the cleanup removed 50% of reads and 33% of transactions on the primary.
How OpenAI delivers low-latency voice AI at scale
OpenAI rebuilt its WebRTC stack for ChatGPT voice and the Realtime API after one-port-per-session media termination collided with Kubernetes: large public UDP ranges, sticky ICE/DTLS ownership, and global first-hop latency. A lightweight Go relay exposes a small fixed UDP surface, reads ICE ufrag routing hints from the first STUN packet, and forwards opaque media to the transceiver that owns ICE, DTLS, and SRTP state (with Redis-backed recovery). Cloudflare geo and proximity steering place signaling near users while Global Relay shortens the first media hop, preserving standard WebRTC for clients without making inference backends WebRTC peers.
Scaling your API with rate limiters
The four kinds of rate limiters and load shedders Stripe uses to protect its API.
Stack Overflow: The Architecture - 2016 Edition
A tour of how Stack Overflow serves a huge site from a small number of powerful servers with heavy caching.