Engineering articles
How a URL shortener actually works under load: redirect latency budgets, cache hierarchies, ClickHouse analytics pipelines, idempotent APIs, and the infrastructure choices behind Elido's edge. These are engineering deep-dives with real numbers from our production systems, written for developers who want to build on a link platform or just enjoy systems design. If you evaluate vendors by their architecture pages, start here.
EngineeringOpen Redirect Vulnerabilities and How to Prevent Them
An open redirect lets an attacker bend a trusted link to a malicious site. How the bug works, why it powers phishing, and the server-side fix that kills it.
6 min readopen redirect vulnerability · open redirect · unvalidated redirect
EngineeringHow to Build a URL Shortener: Architecture and Code
How to build a URL shortener that survives production: short-code generation, the redirect path, caching, click tracking, abuse defense, and what to maintain.
8 min readbuild a url shortener · url shortener system design · short code generation
EngineeringTypes of URL Redirects: 301, 302, 307, 308, and More
Every URL redirect type explained - 301, 302, 303, 307, 308, meta refresh, and JavaScript - what each does, how it affects SEO, and which one to use.
6 min readtypes of redirects · url redirect types · 301 redirect
Engineering301 vs 302 Redirects: Which One Should Short Links Use
A 301 is a permanent redirect that passes ranking signals; a 302 is temporary and usually does not. What that means for short links, SEO, and caching.
7 min read301 vs 302 redirect · 301 redirect · 302 redirect
EngineeringURL Shortener API: Rate Limits, Retries, Idempotency
How to call a URL shortener API in production: token-bucket rate limits, which status codes to retry with backoff, and idempotency keys that stop duplicates.
8 min readurl shortener api rate limits · api idempotency key · retry with exponential backoff
EngineeringDo URL Shorteners Hurt SEO? The Mechanics That Matter
Do URL shorteners hurt SEO? Reputable ones do not - Google passes ranking signals through redirects. The four cases that cost you rank, and how to avoid them.
8 min readdo url shorteners hurt seo · are short links bad for seo · 301 vs 302 redirect seo
EngineeringShort link monitoring with Sentry and Datadog
Forward 4xx/5xx redirect events and edge latency p99 to Sentry as issues and Datadog as metrics. Sample dashboards, alert thresholds.
8 min readshort link monitoring · sentry url monitoring · datadog short link metrics
EngineeringHow Do URL Shorteners Work? The Mechanics Explained
How do URL shorteners work? Store a slug-to-destination mapping, look up the key on each click, return an HTTP redirect. The mechanics, end to end
11 min readhow do url shorteners work · url shortener mechanics · 301 vs 302 redirect
EngineeringShipping the TinyURL migration: Pro/Bulk REST, no free tier
How we built one-click TinyURL Pro/Bulk imports for Elido - why public TinyURL has no API, the alias-vs-slug terminology, and the limit we shipped on purpose.
6 min readtinyurl migration · url shortener · go worker
EngineeringShipping the Short.io migration: per-domain pagination
How we built one-click Short.io imports for Elido: the per-domain pagination model, the deactivated-private-link rule, and our fastest migration source.
6 min readshort.io migration · url shortener · go worker
EngineeringShipping the Rebrandly migration worker
How we built one-click Rebrandly imports for Elido: the 25-per-page pagination, the optional workspace filter, conflict strategies, and what we don't migrate.
6 min readrebrandly migration · url shortener · go worker
EngineeringShipping the Dub.co migration: folders flatten into tags
How we built one-click Dub.co imports for Elido: the cleanest API of the five vendors, folder-to-tag flattening, and the EU-residency side-grade.
7 min readdub.co migration · url shortener · go worker
EngineeringFire-and-forget click ingestion with Redpanda
How edge POPs emit click events without blocking the redirect, how the click-ingester worker batches into ClickHouse, and what we trade away for the latency win
11 min readfire and forget click ingestion · redpanda click events · clickhouse batch insert
EngineeringEdge POPs vs DNS-only routing: the latency budget tradeoff
Why DNS-based load balancing tops out near 50ms p50 and what an anycast edge POP gives you below it, with four numbers that decide which fits your URL shortener
9 min readedge pop vs dns · anycast vs dns failover · edge routing latency
EngineeringCache strategy for URL redirects: L1 LRU and L2 Redis
How a two-tier cache keeps p95 redirect latency under 15ms: the L1 LRU eviction policy, the Redis warming strategy, and failure modes we have seen in production
13 min readurl redirect cache · ristretto lru · redis cluster
CornerstoneEngineeringSentry/GlitchTip across 12 Go services on the hot path
How Elido shipped a shared sentryinit package giving every Go service the same panic + 5xx auto-capture, staying zero-alloc on edge-redirect's hot path.
13 min readsentry go middleware · glitchtip self-hosted · observability url shortener
EngineeringWhy we use ClickHouse for click analytics (and not Postgres)
The workload is 100M+ events/month, write-heavy, analytical-query-shaped. Why columnar wins, the schema we ship, and what we hit at 90 days of Postgres
13 min readclickhouse click analytics · clickhouse for analytics · click event storage
CornerstoneEngineeringHitting p95 < 15ms for redirects from FRA, ASH, and SGP
How Elido's edge-redirect path holds a 15ms p95 budget on cache HIT across three regions - architecture, cache strategy, real-region measurements
15 min readurl shortener performance · edge redirect latency · multi-region url shortener
CornerstoneEngineeringSelf-hosting Elido on k3s - a complete playbook
A step-by-step guide to deploying the full Elido stack on k3s: Helm bootstrap, 14 services, StatefulSet data plane, Caddy on-demand TLS, backups, and upgrades.
13 min readself hosted url shortener · k3s · kubernetes url shortener
CornerstoneEngineeringManage your short links as Terraform with terraform-provider-elido
terraform-provider-elido is the only Terraform provider in the URL-shortener space. How the link lifecycle and drift detection work, plus v0.1.0 trade-offs.
13 min readterraform · infrastructure as code · url shortener
EngineeringShipping the Bitly migration: one worker, four caps
How we built one-click Bitly imports for Elido - the worker design, the conflict-resolution rules, and the four caps that keep an in-process goroutine safe.
8 min readbitly migration · url shortener · go worker