TypeScript's 1:1 validator, optimized from editor to runtime ⛵ ⭐github.com/arktypeio/arktype 👋arktype.io/discord
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📢Introducing ArkRegex📢
a drop in replacement for new RegExp() with types ⬇️
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zod4 is 5x faster than zod3 for object validation.
arktype is 20x faster than zod4.
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Investigating a TypeScript caching issue that could have a *massive* impact for validators like ArkType, Zod and Valibot.
For projects that heavily rely on schema inference like tRPC, fixing this could have a bigger impact than tsgo.
Trigger Warning: O(3^N)
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As of this post, ArkType 2.0 is available and fully stable🎉 (🔗⬇️)
Bring your types to runtime like never before and validate 100x faster.
All with no build step and DX that is 100% guaranteed to blow your mind🤯
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Update on TypeScript's O(3^N) issue:
We have a PR🚀
If we can land this, some schema inference using Zod, Valibot, and ArkType will go from infinite depth to trivial overnight🙏
github.com/microsoft/TypeScr…
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So we've established ArkType is a lot faster than Zod.
What about Yup?
If somehow you are still using it in 2025, your validation could be 3000x faster🤡
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‼️Update on TypeScript's O(3^N) scaling‼️
@AndaristRake's PR has been merged!
If you are struggling with slow types and use one or more of...
✅ a schema library like Zod, Valibot or ArkType
✅ chained methods like .merge
✅ tRPC
The nightly TS build may be a huge W.
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Introducing ArkType 2.1, the first pattern matcher to bring the power of type syntax to JS.
Fully type-safe and up to 100x faster than ts-pattern🧵
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We tested TS Go with ArkType's stress tests:
📈5x faster
📉30% less memory
✅99% correct
Even the craziest types in our repo were perfect on day one🤯
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1️⃣ridiculously good DX
2️⃣better tsserver performance
3️⃣insanely fast runtime validation
4️⃣well-documented and easy to learn
5️⃣power features like generics and HKTs
6️⃣deep introspection + transformation
7️⃣serializable definitions
8️⃣human-readable errors by default
Choose 8.
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Announcing @ark/json-schema, a robust JSON Schema parser for ArkType🔒
If JSON Schema is your source of truth and you want validators that are...
1⃣ crazy fast
2⃣ introspectable
3⃣ great at summarizing errors
today is your lucky day!
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Need JSON Schema for your validator?
Just call toJsonSchema- it's built-in to every type👍
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Ever wished you could just use your TypeScript types at runtime?
With ArkType, you finally can.
All the power of the type system, fully introspectable from native JS- the possibilities are endless🔥
Wow, @arktypeio is gorgeous. Love the simplicity
ALT Declare an arktype schema called `docs.` id set to string "number," content set to string "string." docs is called as a function and returns either ArkErrors or the parsed data
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ArkType 2.2 will automatically validate and infer your regular expressions.
All from TypeScript types🤯
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As of this morning, TS Go can check our repo with zero errors— in 2.5 seconds🤯
That includes...
⚡500 cyclic types in the background of this image
⚡dozens of other inference stress tests
⚡1k+ unit tests w/ complex type assertions
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DO YOU GUYS HAVE ANY IDEA HOW FAST OUR TYPES ARE ABOUT TO GET!?🤯
Today we're thrilled to announce our effort to port the TypeScript compiler and language service to native code, gaining a 10x speed boost in build times and editor responsiveness!
devblogs.microsoft.com/types…
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I'll take "meticulously typed regex features you probably didn't know existed" for $500
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Merging 10 object schemas in ArkType:
TS 5.8 - 1.6M instantiations
TS 5.9 - 18K instantiations
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As TypeScript developers, we rely on our types to know our code will work.
But as our types become complex, how do we know they work?
Unfortunately, existing type testing tools are limited by static analysis- until now.
Introducing @arktype/attest🎉
github.com/arktypeio/arktype…
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📈ArkType just surpassed 1M downloads/month📈
If you still haven't tried it, your friends are now laughing behind your back (statistically speaking).
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Oh, did you guys think we were JOKING when we said we inferred TypeScript syntax 1:1?
We were NOT joking.
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arkregex is a standalone, type-only package that adds types to RegExp.
if you prefer...
🔎 clarity over opacity
🔒 safety over crashing
using it should be the easiest win of your life.
announcement: arktype.io/docs/blog/arkrege…
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All of ArkType boils down to a single question-
how close can we get to TypeScript at runtime?🔬
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Like type-safe environment variables?
Now there's a better way to get them with arkenv⛵❤️
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ArkType is the only validator that can understand how your types relate to one another and optimize them automatically.
That means it can...
✍️describe itself succinctly
🤖skip redundant logic
⚡implicitly discriminate all unions
🔒fail-fast on bad types
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we thought about it and concluded that if you haven't already installed arkregex your project is garbage
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Want to know our secret for writing fast types?
Just build a benchmarking library and spend two years optimizing them.
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⚠️TRADE OFFER ⚠️
you define:
clean, type-safe schemas
you get:
clean, human-readable error messages
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"any sufficiently advanced typescript types are indistinguishable from magic" - Arthur C. Clark, 1962
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ArkType is fast. Really fast.
But in 2025, our value as developers depends on going deeper than ever before.
What matters most is having tools you love to work with so when the time comes, you're ready to lock the f in.
With the ArkType Playground, that DX is one click away.
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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.
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arkregex is ridiculously optimized.
even expressions like this are inferred instantly.
but what about the most extreme cases?🧵
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want 100x faster validation but still not sold on type-safe strings?
just don't use them.
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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
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huge shoutout to @convex for their generous support of arktype🙇
also rumor has it their types are about to get even faster...
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⚠️trade offer⚠️
i receive: JSON Schema
you receive: lightning-fast validation and clear errors
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In 2019, five syllables changed how we think about TypeScript schemas:
Parse, don't validate.
In 2025, we're proud to introduce a new era for runtime validation:
Vibe, don't parse.
Available today in arktype@2.1.42069🚀
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attest is the only assertion library that can snapshot TypeScript autocomplete results📷
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Type-safe functions in pure JS- no JSDoc required.
Want runtime checks? Just enable them.
Should we ship this in 2.2?🤔
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If you like reading simple TypeScript types more than complex regex, keep an eye out for our next release👀
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Why do we reduce every ArkType schema to its simplest form?
⚡optimally discriminated unions
🔒fail-fast on unsatisfiable types
✨clear descriptions and errors
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What if JavaScript function signatures were introspectable and enforced at runtime?
Coming this week in ArkType 2.2.
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ArkType can already infer 100 cyclic types in 100ms.
With TS Go, it will be 10ms.
That is less time than a single Zod .extend today🤯
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If you are a TypeScript developer who...
🪄thinks typed strings are a party trick
🥸has never defined a schema using ArkType
you may be underestimating just how different it is from the half-baked PathString APIs you're used to.
The bar is native-quality DX. Full stop.
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Every part of ArkType's API is designed to mirror TypeScript as closely as possible.
Learning it is less like learning a new library and more like waiting for that parallel to click😌
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Do you ever use branded types?
They're great for enforcing constraints that TypeScript can't, but can sometimes feel unwieldy.
Luckily, using them with ArkType couldn't be simpler👌
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ArkType's `.toJsonSchema()`...
✅exists on every Type
✅great defaults
✅granularly configurable
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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.
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Meet .map(), ArkType's most powerful API for deriving schemas.
Transform keys, values and more with a single call.
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At this rate, it will take Zod 4 *days* to catch up to ArkType on npm.
Hope you're ready to grind @colinhacks ⏳
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want to add your own keywords to arktype?
you don't need a feature request- you need a scope🧑🍳
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We won't be able to ship 2.2 this week.
We really wanted to, but turns out regex types come with a few edge cases.
Sorry, everyone.
We'll do all we can to ship type-level regex that is as robust as our core parser ASAP🙏
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Bringing TypeScript to runtime is about more than just validation.
ArkType 2.1.0 will ship this week, including optimized syntactic pattern matching🔥
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What if instead of hitting instantiation limits on cyclic types, your validator could pass them to optimized, type-safe generics?
Everything you've been told about the limitations of TypeScript is a lie- you just have to be willing to think a bit of outside the box0️⃣1️⃣📦
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Wish TypeScript could error on extra properties?
So do we.
Here's how you can do it in ArkType🧵
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📈ArkType now has >100k weekly npm downloads📈
If you were waiting for docs/stability to try it, now's the perfect time👇
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🔥@t3dotgg's video on @arktype/attest is an amazing intro to type benchmarking- what it is, when you'd use it and who it's important for.
If you haven't already seen it, you're missing out:
Video: piped.video/watch?v=AEA0K77q…
GitHub: github.com/arktypeio/arktype…
It's finally possible to benchmark your TypeScript code thanks to @arktypeio and I HAD to make video about it
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if you're wondering how to do something with ArkType, just ask:
how do i do it with TypeScript?
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@ssalbdivad and @Andarist are looking into this now.
We will let you know once me learn more and, god willing, have a PR soon🙏
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Most validators use chained().methods(). Why "strings"?
✅Inferred 1:1 so you hover less
✅Easily serialized
✅Concise (about half the length of equivalent Zod on average)
✅Typos === type errors
Not convinced? Try it yourself, then let us know why!
github.com/arktypeio/arktype
ALT Most ArkType definitions just look like their TypeScript equivalent- no plugins or extensions required!
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