Choosing an async runtime in 2026
Tokio, smol, async-std and when to pick which. This post digs into the topic, drawing on recent discussion from Hacker News, Reddit, and the wider community.
The conversation that prompted this post is linked in the sources. I have tried to capture the substance of the discussion rather than just summarize it, because the comments are usually where the real insight lives.
What happened
Macros in Rust are powerful but should be used sparingly. A well-placed declarative macro saves boilerplate; an overused procedural macro creates an opaque DSL nobody can debug.
Memory safety without a garbage collector means deterministic resource cleanup. Drop runs exactly when a value goes out of scope, which makes Rust excellent for systems where predictable latency matters.
Cargo is the secret weapon. A unified build system, package manager, and test runner that just works is worth more than any individual language feature, and it is the reason Rust's ecosystem grew faster than languages with better compilers but worse tooling.
Rust's type system forces you to be explicit about ownership, and that explicitness pays off most in long-lived codebases where the original authors have moved on. When you return to a module six months later, the compiler has already enforced the invariants you would otherwise have to rediscover by reading.
Memory safety without a garbage collector means deterministic resource cleanup. Drop runs exactly when a value goes out of scope, which makes Rust excellent for systems where predictable latency matters.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Macros in Rust are powerful but should be used sparingly. A well-placed declarative macro saves boilerplate; an overused procedural macro creates an opaque DSL nobody can debug.
Cargo is the secret weapon. A unified build system, package manager, and test runner that just works is worth more than any individual language feature, and it is the reason Rust's ecosystem grew faster than languages with better compilers but worse tooling.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
The standard library is deliberately small. Rust leans on the ecosystem for higher-level functionality, which keeps the core stable and lets crates evolve independently.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Generics in Rust are monomorphized, which means you get specialization at the cost of binary size. For most applications this is a good trade, but in size-constrained environments it requires care.
Macros in Rust are powerful but should be used sparingly. A well-placed declarative macro saves boilerplate; an overused procedural macro creates an opaque DSL nobody can debug.
The borrow checker is not your enemy. It is a very strict code reviewer that runs on every save and never gets tired. Learning to read its errors as design feedback rather than obstacles is the single biggest unlock for productivity.
Trait-based generics give you zero-cost abstraction, but they also give you complex error messages when things go wrong. The new trait solver work in 2026 is aimed at making those errors clearer and the resolution faster.
Why it matters
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Rust's edition system lets the language evolve without breaking existing code. Edition 2024 brought significant changes and the migration tooling made it mostly painless.
The standard library is deliberately small. Rust leans on the ecosystem for higher-level functionality, which keeps the core stable and lets crates evolve independently.
The borrow checker is not your enemy. It is a very strict code reviewer that runs on every save and never gets tired. Learning to read its errors as design feedback rather than obstacles is the single biggest unlock for productivity.
The standard library is deliberately small. Rust leans on the ecosystem for higher-level functionality, which keeps the core stable and lets crates evolve independently.
The standard library is deliberately small. Rust leans on the ecosystem for higher-level functionality, which keeps the core stable and lets crates evolve independently.
Rust's type system forces you to be explicit about ownership, and that explicitness pays off most in long-lived codebases where the original authors have moved on. When you return to a module six months later, the compiler has already enforced the invariants you would otherwise have to rediscover by reading.
The standard library is deliberately small. Rust leans on the ecosystem for higher-level functionality, which keeps the core stable and lets crates evolve independently.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Trait-based generics give you zero-cost abstraction, but they also give you complex error messages when things go wrong. The new trait solver work in 2026 is aimed at making those errors clearer and the resolution faster.
Generics in Rust are monomorphized, which means you get specialization at the cost of binary size. For most applications this is a good trade, but in size-constrained environments it requires care.
The standard library is deliberately small. Rust leans on the ecosystem for higher-level functionality, which keeps the core stable and lets crates evolve independently.
The standard library is deliberately small. Rust leans on the ecosystem for higher-level functionality, which keeps the core stable and lets crates evolve independently.
Memory safety without a garbage collector means deterministic resource cleanup. Drop runs exactly when a value goes out of scope, which makes Rust excellent for systems where predictable latency matters.
Error handling via Result and Option is verbose but honest. Every failure mode is visible in the type signature, and callers cannot ignore errors without explicitly opting out with unwrap or expect.
Practical takeaways
- Rust's edition system lets the language evolve without breaking existing code.
- Unsafe Rust is a feature, not a bug.
- The borrow checker is not your enemy.
- Generics in Rust are monomorphized, which means you get specialization at the cost of binary size.
- Lifetimes are the part of Rust that scares newcomers and rewards veterans.
- Error handling via Result and Option is verbose but honest.
- The borrow checker is not your enemy.
- Unsafe Rust is a feature, not a bug.
- Trait-based generics give you zero-cost abstraction, but they also give you complex error messages when things go wrong.
- Cargo is the secret weapon.
Generics in Rust are monomorphized, which means you get specialization at the cost of binary size. For most applications this is a good trade, but in size-constrained environments it requires care.
Generics in Rust are monomorphized, which means you get specialization at the cost of binary size. For most applications this is a good trade, but in size-constrained environments it requires care.
Unsafe Rust is a feature, not a bug. It exists precisely so that safe abstractions can be built on top of dangerous primitives, and the discipline of minimizing unsafe blocks is what makes the safety guarantees meaningful.
Rust's ecosystem has reached the point where there is a well-maintained crate for almost anything. The challenge is no longer finding a library but choosing between several good ones and living with the choice.
Error handling via Result and Option is verbose but honest. Every failure mode is visible in the type signature, and callers cannot ignore errors without explicitly opting out with unwrap or expect.
Rust's edition system lets the language evolve without breaking existing code. Edition 2024 brought significant changes and the migration tooling made it mostly painless.
Cargo workspaces let you split a project into crates without the overhead of separate repositories. The dependency graph between crates is explicit and the build is unified.
Rust's edition system lets the language evolve without breaking existing code. Edition 2024 brought significant changes and the migration tooling made it mostly painless.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Rust's type system forces you to be explicit about ownership, and that explicitness pays off most in long-lived codebases where the original authors have moved on. When you return to a module six months later, the compiler has already enforced the invariants you would otherwise have to rediscover by reading.
Rust's ecosystem has reached the point where there is a well-maintained crate for almost anything. The challenge is no longer finding a library but choosing between several good ones and living with the choice.
The standard library is deliberately small. Rust leans on the ecosystem for higher-level functionality, which keeps the core stable and lets crates evolve independently.
The standard library is deliberately small. Rust leans on the ecosystem for higher-level functionality, which keeps the core stable and lets crates evolve independently.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Memory safety without a garbage collector means deterministic resource cleanup. Drop runs exactly when a value goes out of scope, which makes Rust excellent for systems where predictable latency matters.
The borrow checker is not your enemy. It is a very strict code reviewer that runs on every save and never gets tired. Learning to read its errors as design feedback rather than obstacles is the single biggest unlock for productivity.
Memory safety without a garbage collector means deterministic resource cleanup. Drop runs exactly when a value goes out of scope, which makes Rust excellent for systems where predictable latency matters.
Unsafe Rust is a feature, not a bug. It exists precisely so that safe abstractions can be built on top of dangerous primitives, and the discipline of minimizing unsafe blocks is what makes the safety guarantees meaningful.
Cargo is the secret weapon. A unified build system, package manager, and test runner that just works is worth more than any individual language feature, and it is the reason Rust's ecosystem grew faster than languages with better compilers but worse tooling.
Sources
This post is informed by discussion on tokio.rs and related threads on Hacker News and Reddit. Primary source: https://tokio.rs/.
The borrow checker is not your enemy. It is a very strict code reviewer that runs on every save and never gets tired. Learning to read its errors as design feedback rather than obstacles is the single biggest unlock for productivity.
Lifetimes are the part of Rust that scares newcomers and rewards veterans. Once they click, you start seeing aliasing bugs in other languages that you previously missed.
Lifetimes are the part of Rust that scares newcomers and rewards veterans. Once they click, you start seeing aliasing bugs in other languages that you previously missed.
Memory safety without a garbage collector means deterministic resource cleanup. Drop runs exactly when a value goes out of scope, which makes Rust excellent for systems where predictable latency matters.
Macros in Rust are powerful but should be used sparingly. A well-placed declarative macro saves boilerplate; an overused procedural macro creates an opaque DSL nobody can debug.
Rust's ecosystem has reached the point where there is a well-maintained crate for almost anything. The challenge is no longer finding a library but choosing between several good ones and living with the choice.
Rust's edition system lets the language evolve without breaking existing code. Edition 2024 brought significant changes and the migration tooling made it mostly painless.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Macros in Rust are powerful but should be used sparingly. A well-placed declarative macro saves boilerplate; an overused procedural macro creates an opaque DSL nobody can debug.
Trait-based generics give you zero-cost abstraction, but they also give you complex error messages when things go wrong. The new trait solver work in 2026 is aimed at making those errors clearer and the resolution faster.
The borrow checker is not your enemy. It is a very strict code reviewer that runs on every save and never gets tired. Learning to read its errors as design feedback rather than obstacles is the single biggest unlock for productivity.
The standard library is deliberately small. Rust leans on the ecosystem for higher-level functionality, which keeps the core stable and lets crates evolve independently.
Error handling via Result and Option is verbose but honest. Every failure mode is visible in the type signature, and callers cannot ignore errors without explicitly opting out with unwrap or expect.
Error handling via Result and Option is verbose but honest. Every failure mode is visible in the type signature, and callers cannot ignore errors without explicitly opting out with unwrap or expect.
Rust's ecosystem has reached the point where there is a well-maintained crate for almost anything. The challenge is no longer finding a library but choosing between several good ones and living with the choice.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Macros in Rust are powerful but should be used sparingly. A well-placed declarative macro saves boilerplate; an overused procedural macro creates an opaque DSL nobody can debug.
Cargo is the secret weapon. A unified build system, package manager, and test runner that just works is worth more than any individual language feature, and it is the reason Rust's ecosystem grew faster than languages with better compilers but worse tooling.
Error handling via Result and Option is verbose but honest. Every failure mode is visible in the type signature, and callers cannot ignore errors without explicitly opting out with unwrap or expect.
Error handling via Result and Option is verbose but honest. Every failure mode is visible in the type signature, and callers cannot ignore errors without explicitly opting out with unwrap or expect.
Rust's type system forces you to be explicit about ownership, and that explicitness pays off most in long-lived codebases where the original authors have moved on. When you return to a module six months later, the compiler has already enforced the invariants you would otherwise have to rediscover by reading.
Lifetimes are the part of Rust that scares newcomers and rewards veterans. Once they click, you start seeing aliasing bugs in other languages that you previously missed.
Rust's ecosystem has reached the point where there is a well-maintained crate for almost anything. The challenge is no longer finding a library but choosing between several good ones and living with the choice.
Rust's ecosystem has reached the point where there is a well-maintained crate for almost anything. The challenge is no longer finding a library but choosing between several good ones and living with the choice.
Error handling via Result and Option is verbose but honest. Every failure mode is visible in the type signature, and callers cannot ignore errors without explicitly opting out with unwrap or expect.
The borrow checker is not your enemy. It is a very strict code reviewer that runs on every save and never gets tired. Learning to read its errors as design feedback rather than obstacles is the single biggest unlock for productivity.
Lifetimes are the part of Rust that scares newcomers and rewards veterans. Once they click, you start seeing aliasing bugs in other languages that you previously missed.
Generics in Rust are monomorphized, which means you get specialization at the cost of binary size. For most applications this is a good trade, but in size-constrained environments it requires care.
Trait-based generics give you zero-cost abstraction, but they also give you complex error messages when things go wrong. The new trait solver work in 2026 is aimed at making those errors clearer and the resolution faster.
Macros in Rust are powerful but should be used sparingly. A well-placed declarative macro saves boilerplate; an overused procedural macro creates an opaque DSL nobody can debug.
The borrow checker is not your enemy. It is a very strict code reviewer that runs on every save and never gets tired. Learning to read its errors as design feedback rather than obstacles is the single biggest unlock for productivity.
Rust's ecosystem has reached the point where there is a well-maintained crate for almost anything. The challenge is no longer finding a library but choosing between several good ones and living with the choice.
Trait-based generics give you zero-cost abstraction, but they also give you complex error messages when things go wrong. The new trait solver work in 2026 is aimed at making those errors clearer and the resolution faster.
Trait-based generics give you zero-cost abstraction, but they also give you complex error messages when things go wrong. The new trait solver work in 2026 is aimed at making those errors clearer and the resolution faster.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Unsafe Rust is a feature, not a bug. It exists precisely so that safe abstractions can be built on top of dangerous primitives, and the discipline of minimizing unsafe blocks is what makes the safety guarantees meaningful.
Macros in Rust are powerful but should be used sparingly. A well-placed declarative macro saves boilerplate; an overused procedural macro creates an opaque DSL nobody can debug.
Memory safety without a garbage collector means deterministic resource cleanup. Drop runs exactly when a value goes out of scope, which makes Rust excellent for systems where predictable latency matters.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Cargo is the secret weapon. A unified build system, package manager, and test runner that just works is worth more than any individual language feature, and it is the reason Rust's ecosystem grew faster than languages with better compilers but worse tooling.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.
Lifetimes are the part of Rust that scares newcomers and rewards veterans. Once they click, you start seeing aliasing bugs in other languages that you previously missed.
Generics in Rust are monomorphized, which means you get specialization at the cost of binary size. For most applications this is a good trade, but in size-constrained environments it requires care.
The standard library is deliberately small. Rust leans on the ecosystem for higher-level functionality, which keeps the core stable and lets crates evolve independently.
Cargo is the secret weapon. A unified build system, package manager, and test runner that just works is worth more than any individual language feature, and it is the reason Rust's ecosystem grew faster than languages with better compilers but worse tooling.
Error handling via Result and Option is verbose but honest. Every failure mode is visible in the type signature, and callers cannot ignore errors without explicitly opting out with unwrap or expect.
Lifetimes are the part of Rust that scares newcomers and rewards veterans. Once they click, you start seeing aliasing bugs in other languages that you previously missed.
Error handling via Result and Option is verbose but honest. Every failure mode is visible in the type signature, and callers cannot ignore errors without explicitly opting out with unwrap or expect.
The standard library is deliberately small. Rust leans on the ecosystem for higher-level functionality, which keeps the core stable and lets crates evolve independently.
Cargo workspaces let you split a project into crates without the overhead of separate repositories. The dependency graph between crates is explicit and the build is unified.
Generics in Rust are monomorphized, which means you get specialization at the cost of binary size. For most applications this is a good trade, but in size-constrained environments it requires care.
Error handling via Result and Option is verbose but honest. Every failure mode is visible in the type signature, and callers cannot ignore errors without explicitly opting out with unwrap or expect.
Macros in Rust are powerful but should be used sparingly. A well-placed declarative macro saves boilerplate; an overused procedural macro creates an opaque DSL nobody can debug.
Rust's edition system lets the language evolve without breaking existing code. Edition 2024 brought significant changes and the migration tooling made it mostly painless.
Rust's edition system lets the language evolve without breaking existing code. Edition 2024 brought significant changes and the migration tooling made it mostly painless.
Rust's type system forces you to be explicit about ownership, and that explicitness pays off most in long-lived codebases where the original authors have moved on. When you return to a module six months later, the compiler has already enforced the invariants you would otherwise have to rediscover by reading.
Error handling via Result and Option is verbose but honest. Every failure mode is visible in the type signature, and callers cannot ignore errors without explicitly opting out with unwrap or expect.
Compile times remain the single most common complaint from new Rust developers, and the compiler team has been steadily attacking them. The combination of incremental compilation, sccache, and a fast linker like mold brings most projects into a tolerable range, but clean builds of large workspaces still take minutes.