If you've ever needed your public IP in a script, you've probably typed this:
curl api.ipify.org
ipify is one of those quiet pieces of internet infrastructure. Launched in 2014, it answers one question — "what is my public IP?" — so simply that it ended up embedded in millions of scripts and apps, serving billions of requests a month. Respect.
But a while ago I noticed something while browsing its GitHub repo: the last code change was January 2018. Community pull requests — CORS headers, Docker support, even one-line README fixes — have been sitting unanswered for years. The hosted service still runs (it's commercially operated by WhoisXML API), but the open-source project that made developers trust it is effectively frozen. And geolocation was never part of the free deal — it's a separate paid product.
That gap looked like an invitation. We run whatsmy.fyi, an IP and network info tool, and we decided to build the thing we wished existed. Here's what we shipped and — more usefully — what we learned along the way.
What we built
A keyless endpoint that's deliberately compatible with ipify's response format:
# Plain text
curl https://whatsmy.fyi/ip
# → 203.0.113.42
# JSON — identical shape to api.ipify.org
curl "https://whatsmy.fyi/ip?format=json"
# → {"ip":"203.0.113.42"}
Swapping it into existing code is a one-URL change. No key, no signup, CORS enabled, IPv4 + IPv6, nothing logged.
When you need more than the bare IP, a free API key (10,000 requests/day) returns city, country, coordinates, timezone, ASN, and ISP — the data ipify sells separately. There's also a TypeScript SDK with a keyless mode:
import { WhatsMyFyi } from '@whatsmyfyi/sdk'
const client = new WhatsMyFyi() // no key needed
const ip = await client.ip.address() // "203.0.113.42"
Lesson 1: friction decides everything in this category
Our API originally required a key for everything. Reasonable, right? Usage tracking, rate limits, dashboards.
Wrong — at least for this use case. The entire reason curl api.ipify.org won the internet is that it works before you've decided to care. A developer comparing IP APIs closes the tab the moment they see "sign up first." We realized the keyless endpoint wasn't a nice-to-have; it was the price of admission. The authenticated API now earns its keep as the upgrade path, not the front door.
Lesson 2: the edge changed the economics
ipify's era required choices: serving geolocation means licensing a GeoIP database, updating it, and eating lookup latency. Charging for geo made sense in 2014.
Running on Cloudflare Workers changed that math for us. Every request already arrives with geolocation, ASN, and timezone attached (the request.cf object) — data from the network itself, with no external database call. Serving "rich" IP data now costs us roughly the same as serving the bare IP. That's not cleverness on our part; it's a structural shift that makes the old free-IP/paid-geo split feel dated.
Lesson 3: honesty is a feature you can ship
We published a comparison page covering ipify, icanhazip, ip-api.com, ipapi.co, and ipinfo — and we verified every claim by calling each API ourselves (ip-api.com really does reject HTTPS on the free tier; ipapi.co really did 429 our first request). The page also lists the places where competitors beat us, and recommends icanhazip for shell scripts and ipinfo for enterprise needs, because that's the truth.
This felt risky to write. But developers can smell a rigged comparison table from a mile away; an honest one is rare enough to be memorable — and it gives every claim on the page a "verify it yourself" quality that no marketing copy can match.
Lesson 4: maintenance is the moat
Here's the uncomfortable part: nothing we built is technically hard. A keyless IP endpoint is a weekend project. What ipify's story actually demonstrates is that the hard part is still being there — answering issues, merging PRs, shipping releases — years after the launch excitement fades.
So we wrote the only durable differentiator we could into our CONTRIBUTING.md: every issue and PR gets a human response within a few days. If we ever stop honoring that, someone should build the whatsmy.fyi alternative — and they'd be right to.
Links
- Keyless endpoint:
curl https://whatsmy.fyi/ip
API docs · OpenAPI spec
SDK on GitHub · npm
- The full comparison
Questions, criticism, and "actually you got X wrong" comments are genuinely welcome — that's how the comparison page stays honest.