You describe your events and functions, and what they carry, in a .blink schema. The compiler generates a server module and a client module in plain Luau: functions and buffer calls, with no metatables and no runtime library beside them. They pack every call into one buffer per frame, check everything a client sends before your code sees it, and keep working when a client is hostile.

event Damage {
	From: Client,
	Type: Reliable,
	Call: SingleSync,
	Rate: 10,
	Data: struct { Target: Instance(Humanoid), Amount: u8(1..100) }
}

-- Server: the listener runs only after the rate limit has passed and Amount is 1..100.
Net.Damage.On(function(Player, Hit)
	Combat.Apply(Player, Hit.Target, Hit.Amount)
end)

-- Client
Net.Damage.Fire({ Target = Humanoid, Amount = 25 })

Why BlinkBlox

• Bounded inbound traffic. Packet size, the number of events in a packet and the number of instance references are capped before anything is parsed. Each player also gets a byte budget.
• Rate limits per player and per event. Set Rate and Burst on an event, or a default for the whole schema, and Concurrency on a function to bound the calls still running. Refused events go to a handler you provide, and nobody is kicked automatically.
• Hostile input costs the attacker, not the server. Every length is checked before the read and the allocation it pays for. A malformed event ends its packet without throwing: the events before it are delivered, and the failure goes to a handler you provide.
• A missing Instance costs one event, not the packet. Under StreamingEnabled an Instance the sender had often is not there on arrival. That event alone is refused and reported; the rest of the packet is still read, at no cost to decoding when everything arrives.
• Mistakes other libraries leave silent are named. A second copy of the module in an Actor errors at require, a send made with : instead of . says so, a function's listener replaced by a second .On warns, a client left waiting for a server that never started says why, and a file of events imported twice warns at compile time. The client's queues are capped as the server's are.
• Mismatched builds refuse each other. A client and a server built from different schemas stop at startup instead of decoding one event as another.
• The Roblox types games send. Vector2, UDim, UDim2, NumberRange, ColorSequence, TweenInfo, and a Roblox enum's items as Enum(Material) -- sent by Value, never by list position, which can differ between client and server during an engine rollout.
• Small on the wire. Booleans, optional flags, enum values and tags share a bitfield, and boolean[] packs eight to a byte. A length is sent relative to its range, a short one in a single varint byte, CFrame<quat> fits a rotation in 7 bytes, and u24, i24 and f24 fill the gap between 16 and 32 bits, so vector<f24> is 9 bytes instead of 12. A float with a step and a range is quantized: f32<0.01>(-1..1) is one byte. An unreliable event that cannot fit is refused at compile time.
• Few remote calls. A FireAll goes to every player in one FireAllClients, streams to everyone share one packet a frame, and BatchUnreliable gathers a frame's unreliable events the same way. A client cuts its batch to fit the server's limits, so an honest player is never refused, and sends at most 60 times a second, since every remote call costs about 11 bytes of its own.
• An outbound budget. Give each player a byte budget for what the server sends, and mark the events and streams that may wait with Priority: Low; nothing else is ever held back.
• Tooling. The CLI has watch mode and @profile builds that keep debug remotes out of release, --check --json reports every diagnostic as JSON for editors and AI assistants, and --verify fails a pre-commit hook or CI step when the committed modules no longer match the schema. The generated modules pass their own --!strict, and keep their types under the new type solver however many events the schema has. You also get TypeScript definitions and a Studio plugin with live diagnostics.

Performance

Speed is not the reason to choose BlinkBlox. A reader written by hand for one event can be as fast as anything generated for it, and Compared with hand-written buffers says when that is the better choice. The numbers are here to compare tools that do the same job, and to hold each release to the one before it: nothing may get slower.

Each tool fires 1000 events a frame from client to server, on LuneBlox -- the Luau version and flags Roblox runs, without Roblox -- on an Intel Core i7-13700K with BlinkBlox 0.42.0, on 2026-09-28. Each figure is the median of three runs, every tool in a process of its own. Blink is the original project BlinkBlox forked from, at its last release, 0.18.9. "Send" is a frame's thousand fires and the flush into a packet, interpreted, as most players' clients run it; "decode" is the server decoding them, natively compiled, as a Roblox server runs it; bytes are one event before compression.

Tool	1000 booleans: send / decode	100 entities: send / decode	Bytes, booleans / entities
BlinkBlox	16.3 / 6.7 ms	12.1 / 3.6 ms	128 / 602
Blink	29.3 / 10.7 ms	12.8 / 21.8 ms	1003 / 603
zap	65.5 / 11.5 ms	33.4 / 21.2 ms	1003 / 603
ByteNet	54.2 / 51.0 ms	42.7 / 42.5 ms	1003 / 603
Packet	54.0 / 51.0 ms	39.9 / 52.7 ms	1003 / 603
QuickNet	16.8 / 7.5 ms	21.7 / 11.4 ms	128 / 603
Warp	38.5 / 11.5 ms	65.7 / 26.9 ms	128 / 602

The gap depends on the payload: against zap the server decodes 1.7 times faster on booleans and 5.9 times on entities, and QuickNet is close behind on booleans.

The frame rates in Studio, a server sending to fifty players, unreliable inputs, a schema of 128 events, the bandwidth and the methodology are in Benchmarks and benchmark/Benchmarks.md. What 1.0.0 changed is in What's new in 1.0.

Where it comes from

BlinkBlox is a maintained fork of Blink. Upstream froze this line of the compiler and began a rewrite. It left reported defects open, including an unbounded parse of a hostile client buffer. This fork fixes them and continues from v0.18.8. See Migrating from Blink.

Install

rokit add XopoIII/BlinkBlox blinkblox             # CLI through Rokit
pesde add xopoiii/blinkblox --dev --target lune   # or through pesde

Binaries for every platform, and the Studio plugin (blinkblox-plugin.rbxm), are attached to each release. The plugin is also on the Creator Store as BlinkBlox Editor. Code that runs the compiler inside Roblox -- a plugin, an in-Studio build step -- can take it from Wally as xopoiii/blinkblox. See Installation.

Contributing

rokit install              # toolchain
sh scripts/run-tests.sh    # test suite
cd docs && npm install && npm run dev   # documentation site

CLAUDE.md describes the architecture and the gates that CI and the git hooks run.

License

MIT. See LICENSE. Originally written by Axen; this fork continues from v0.18.8 and keeps the upstream copyright.