our two-step process for fast typescript types: 1️⃣ build a type-level benchmarking library 2️⃣ spend the prime of your life on cache optimizations

Today on the pod, learn how ArkType's 1:1 validator provides soundness guarantees beyond vanilla TypeScript, with type-level parsing & JIT optimization! share.transistor.fm/s/8f206643 #typescript

attest can snapshot types, type errors and autocomplete results. all from your existing unit tests📚🔗⬇️

⚠️trade offer⚠️ i receive: JSON Schema you receive: lightning-fast validation and clear errors

How to use ArkType: 1️⃣ write typescript 2️⃣ use it in editor 3️⃣ use it at runtime

turns out having type syntax at runtime is pretty nice

1️⃣ start with a typescript keyword 2️⃣ .autocomplete the rest

zod4 is 5x faster than zod3 for object validation. arktype is 20x faster than zod4.

JSON Schema: Making illegal states representable since 2007

typescript is crazy

you deserve better type errors

challenge: create an unsatisfiable arktype schema difficulty: mathematically impossible

you haven't lived until you've seen autocomplete for "string | n" try it in-browser 🛝🔗👇

🌶️hover clarity is a huge part of typescript dx

1️⃣ type.validate 2️⃣ type.infer all your API needs to accept an ArkType definition with autocomplete, type-level errors and inference.

ArkType can granularly configure 11 non-JSON-schemafiable constraints... or just do this and say "f*** it, we ball"😎

ArkType's `.toJsonSchema()`... ✅exists on every Type ✅great defaults ✅granularly configurable

want to add your own keywords to arktype? you don't need a feature request- you need a scope🧑‍🍳

love to see it. writing complex types without @ark/attest is like running benchmarks with an hourglass⌛

Wish TypeScript could error on extra properties? So do we. Here's how you can do it in ArkType 🧵

1️⃣s-tier DX 2️⃣ridiculous tsserver perf 3️⃣insanely fast runtime validation 4️⃣great documentation 5️⃣power features (generics and HKTs) 6️⃣deep introspectability 7️⃣serializable definitions 8️⃣human-readable errors 9️⃣universal composability 🔟easy to learn Choose 10.

Extracting keys in ArkType🔑

@arktype.io schemas 👉👈 JSON-serializable TypeScript

z.z.z.z.z.z.z.z.z.z💤

All of ArkType boils down to a single question- how close can we get to TypeScript at runtime?🔬

gonna be golden✨

cleanest defaults you've ever seen or your money back💰

Meet .map(), ArkType's most powerful API for deriving schemas. Transform keys, values and more with a single call.

📈ArkType's Discord community is growing fast and just surpassed 750 members!📈 Have questions? Want to stay up to date? It's a great time to join! arktype.io/discord

Why does ArkType use "strings" over .chaining()? ✅Inferred 1:1 so you hover less ✅Easily serialized ✅Concise (~30-50% shorter than Zod) ✅Typos === type errors

index signatures? more like *fun*dex signatures👍

📈ArkType just surpassed 1M downloads/month📈 If you *still* haven't tried it, your friends are now laughing behind your back (statistically speaking).

Need runtime validation for your existing types? ArkType's `declare` API gives you just that.

@ark/attest is the only assertion library that can snapshot TypeScript autocomplete results 📷

Restrict the size of numbers, strings and arrays with expressive, type-safe syntax.

"don't worry babe. with Standard Schema, developers won't have to choose"

two possibilities: 🅰️ your typescript strings have native-quality autocomplete 🅱️ skill issue

MASSIVE shout out to @jdegoes.bsky.social for his incredibly generous support of @arktype.io. An absolute legend and one of the best speakers I've ever heard🙇

Love great error messages but hate writing them? Out of the box, @arktype.io errors are... 1️⃣clear and concise 2️⃣readable for developers and end users 3️⃣deeply customizable to your needs

How is ArkType's autocomplete so fast and accurate? ✅100+ type-level benchmarks ✅1k+ type-level unit tests

bUt sTriNgs CaNt bE TypEsAfe

Zod is a great library. It is not realistic to be as proficient with a new validator on your first day using it, even with good docs and an intuitive API. That doesn't mean there aren't significant benefits.

If you can type it with TypeScript, you can validate it with @arktype.io 🤝

TypeScript + runtime = ArkType

ArkType has dozens of subtype keywords to keep your schemas simple and readable. Type `string.` and see for yourself!

problem: switch statements are garbage solution: pnpm i arktype

When to enable noErrorTruncation in your tsconfig: ✅you want to read a long error message 🤔you want to expand a long type hover 🤡you want to get trolled out of your goddamn mind

Validating dates has never been easier📅🎆

if you're still manually discriminating your schemas in 2025, you're ngmi

ArkType scopes make defining and configuring custom keywords and cyclic types a breeze🍃