SQLx – Rust SQL Toolkit
47 comments
·July 26, 2025bitbasher
jchw
Speaking of Go, if you want compile-time type checking like what SQLx offers, the Go ecosystem has an option that is arguably even better at it:
It has the advantage that it implements the parsing and type checking logic in pure Go, allowing it to import your migrations and infer the schema for type checking. With SQLx you need to have your database engine running at compile time during the proc macro execution with the schema already available. This makes SQLx kind of a non-starter for me, though I understand why nobody wants to do what sqlc does (it involves a lot of duplication that essentially reimplements database features.) (Somewhat ironically it's less useful for sqlc to do this since it runs as code generation outside the normal compilation and thus even if it did need a live database connection to do the code generation it would be less of an impact... But it's still nice for simplicity.)
bitbasher
It's possible to run sqlx in 'offline' mode that uses your schema to do the checks so you don't need a live database. That's a popular option in CI/CD scenarios.
jjice
It's absolutely core to SQLx. I'm surprised to hear that that isn't widely known based on the parent. The first time I used SQLx has to be 4 or 5 years ago and they had it back then.
echelon
Offline query caching is great. The team has made it work fantastically for workspace oriented monorepos too.
I ran sqlx / mysql on a 6M MAU Actix-Web website with 100kqps at peak with relatively complex transactions and queries. It was rock solid.
I'm currently using sqlx on the backend and on the desktop (Tauri with sqlite).
In my humble opinion, sqlx is the best, safest, most performant, and most Rustful way of writing SQL. The ORMs just aren't quite there.
I wish other Rust client libraries were as nice as sqlx. I consider sqlx to be one of Rust's essential crates.
tizzy
I never gelled with how SQLC needs to know about your schema via the schema file. I'm used to flyway where you can update the schema as long as it's versioned correctly such that running all the sets of flyways will produce the same db schema.
I referred go-jet since it introspects the database for it's code generation instead.
jchw
The way I prefer to use sqlc is in combination with a schema migration framework like goose. It actually is able to read the migration files and infer the schema directly without needing an actual database. This seems to work well in production.
frollogaston
This is why I like using NodeJS or Python with SQL, it's very simple to have it not care about the return types. SQL is already statically typed per se, I don't need to re-assert everything. Achieving the same kind of automation in Go etc requires parsing the schema at compile-time like what you described, which is complicated.
written-beyond
I spent 2 weeks trying to build a very basic rest crud API with SQLc and it was not better. I had to shift to SQLx because of how unintuitive SQLc was.
devjab
We've been running SQLC in production for a while now and I'm curious which part of it you found unintuitive? We run ours as a container service within the development environment that will compile your code from a postgres dump file. We've had no issues with it at all after the initial configuration guidelines for SQLC, though the documentation certainly isn't exactly great. Hell, I'm not sure I've ever worked with a better SQL to language tool in my decades so I'm surprised that it isn't working out for you.
That being said, as I understand it, SQLx does something very different. If you want dynamic queries, you'll basically have to build that module yourself. The power of SQLC is that anyone who can write SQL can work on the CRUD part of your Go backend, even if they don't know Go. Hell, we've even had some success with business domain experts who added CRUD functionality by using LLM's to generate SQL. (We do have a lot of safeguards around that, to make it less crazy than it sounds).
If you want fancy Linq, grapQL, Odata or even a lot of REST frameworks, you're not getting any of that with SQLC though, but that's typically not what you'd want from a Go backend in my experience. Might as well build it with C# or Java then.
happens
Interesting - I've had the opposite experience. I usually prefer rust for personal projects, but when I recently tried to use SQLx with sqlite, lots of very basic patterns presented problems, and I wished I had sqlc back.
Thaxll
imo sqlc from Go is supperior to sqlx from Rust. The other thing is that sqlx is somehow slow, when I did some test, pgx ( Go ) was faster than sqlx.
frollogaston
How is it more LoC in Go, just cause of the "if err" stuff?
null
karlmdavis
I find it kind of baffling that this toolkit is so popular when it makes handling database joins so difficult. After bashing my head against it for a while, I moved to Diesel, and while that has its own set of problems, I am generally able to get through them without resorting to horrible hacks or losing compile time checks.
moggers123
SQLx is great, but I really wish they had a non-async interface. I had to switch a project from sqlx to rusqlite seemingly just due to the overhead of the async machinery. Saw a 20x latency reduction that I narrowed down to "probably async" (sort of hard to tell, I find it very difficult to do perf analysis of async code). I try to avoid discussing async so as to not come off as a frothing-at-the-mouth-chest-thumping-luddite but honestly, if sqlx had a non-async interface I'd be very happy to accept the "you don't need to use it" argument. its the only place where I don't feel like I really have a choice.
tmpfs
I have used this as well as many of the other lower-level db drivers (which don't check your SQL at compile time) and I can say I much prefer the latter.
My issues with SQLx when I first tried it were that it was really awkward (nigh impossible) to abstract away the underlying DB backend, I expect those issues are fixed now but for some simple apps it's nice to be able to start with SQLite and then switch out with postgres.
Then I wanted to dockerize an SQLx app at one point and it all becomes a hassle as you need postgres running at compile time and trying to integrate with docker compose was a real chore.
Now I don't use SQLx at all. I recommend other libraries like sqlite[1] or postgres[2] instead.
SQLx is a nice idea but too cumbersome in my experience.
[1]: https://docs.rs/sqlite/latest/sqlite/ [2]: https://docs.rs/postgres/latest/postgres/
belak
I'm have no experience with abstracting away the backend, but Dockerizing is actually pretty easy now - there's an offline mode[1] where you can have sqlx generate some files which let it work when there's no DB running.
[1]: https://docs.rs/sqlx/latest/sqlx/macro.query.html#offline-mo...
vegizombie
It's definitely not perfect, but I think both of those issues are better now, if not fully solved.
For needing a DB at compile time, there's an option to have it produce artefacts on demand that replace the DB, although you'll need to connect to a DB again each time your queries change. Even that is all optional though, if you want it to compile time check your queries.
adelmotsjr
Why would you want to abstract away the underlying database? Wouldn't it better to already use the target DB to cattch potential issues earlier? Also to avoid creating another layer of indirection, potentially complecting the codebase and reducing performance?
TrueDuality
Primarily for libraries and deployment environments that aren't fully in your control which is still pretty common once you get to B2B interactions, SaaS is not something you can easily sell to certain environments. Depending on the assurance you need, you might even need to mock out the database entirely to test certain classes of database errors being recoverable or fail in a consistent state.
Even in SaaS systems, once you get large enough with a large enough test suite you'll be wanting to tier those tests starting with a lowest common denominator (sqlite) that doesn't incur network latency before getting into the serious integration tests.
0xCMP
I know it's annoying (and apparently there is a solution for generating the required files before the build), but in these kinds of situations Go and Rust are great for doing a static build on the system and then copying into a scratch image.
Versus Python and Node often needing to properly link with the system they'll actually be running in.
stmw
Thanks, interesting experience - so much depends on getting developer ergonomics right. There is something to be said for checking the SQL at compile-time, though - esp. if trying to ORM to a typesafe language.
no_circuit
How long ago did you try SQLx? Not necessarily promoting SQLX, but the `query_as` which lets one make queries without the live database macro has been around for 5 years [1].
For lower level libraries there is also the more downloaded SQLite library, rusqlite [2] who is also the maintainer of libsqlite3-sys which is what the sqlite library wraps.
The most pleasant ORM experience, when you want one, IMO is the SeaQl ecosystem [3] (which also has a nice migrations library), since it uses derive macros. Even with an ORM I don't try to make databases swappable via the ORM so I can support database-specific enhancements.
The most Rust-like in an idealist sense is Diesel, but its well-defined path is to use a live database to generate Rust code that uses macros to then define the schema-defining types which are used in the row structs type/member checking. If the auto-detect does not work, then you have to use its patch_file system that can't be maintained automatically just through Cargo [4] (I wrote a Makefile scheme for myself). You most likely will have to use the patch_file if you want to use the chrono::DateTime<chrono::Utc> for timestamps with time zones, e.g., Timestamp -> Timestamptz for postgres. And if you do anything advanced like multiple schemas, you may be out of luck [5]. And it may not be the best library for you if want large denormalized tables [6] because compile times, and because a database that is not normalized [7], is considered an anti-pattern by project.
If you are just starting out with Rust, I'd recommend checking out SeaQl. And then if you can benchmark that you need faster performance, swap out for one of the lower level libraries for the affected methods/services.
[1] https://github.com/launchbadge/sqlx/commit/47f3d77e599043bc2...
[2] https://crates.io/crates/rusqlite
[3] https://www.sea-ql.org/SeaORM/
[4] https://github.com/diesel-rs/diesel/issues/2078
[5] https://github.com/diesel-rs/diesel/issues/1728
Ameo
sqlx is my favorite way of working with databases in Rust hands down.
I've tried alternatives like Diesel and sea-orm. To be honest, I feel like full-blown ORMs really aren't a very good experience in Rust. They work great for dynamic languages in a lot of cases, but trying to tie in a DB schema into Rust's type system often creates a ton of issues once you try to do anything more than a basic query.
It's got a nice little migration system too with sqlx-cli which is solid.
theOGognf
I’ve used Diesel for a bit now but haven’t had issues wrangling the type system. Can you give an example of an issue you’ve encountered?
p4ul
This has been exactly my experience! I've found SQLx to be a joy to work with in Rust!
null
WD-42
Same. Never again diesel. The type system just turns it into madness. Sqlx is a much more natural fit.
thesuperbigfrog
I used SQLx with an SQLite database and ran into connection pool problems that would cause the database to be unexpectedly dropped.
The issues I saw seem to be related to these issues:
https://github.com/launchbadge/sqlx/issues/3080
https://github.com/launchbadge/sqlx/issues/2510
The problems did not manifest until the application was under load with multiple concurrent sessions.
Troubleshooting the issue by changing the connection pool parameters did not seem to help.
I ended up refactoring the application's data layer to use a NoSQL approach to work around the issue.
I really like the idea of SQLx and appreciate the efforts of the SQLx developers, but I would advise caution if you plan to use SQLx with SQLite.
cortesi
SQLx is great, but I had a long laundry list of issues with its SQLite support so I forked it into a focused SQLite-specific library. It has now diverged very far from SQLx, and the number of small inaccuracies and issues we fixed in the low-level SQLite bindings is well into the dozens. The library is unannounced, but is already being used in some high-throughput scenarios.
zbentley
As a total outsider to sqlx, those issues don’t surprise me: any application on any platform that uses a SQLite in-memory DB concurrently is likely to violate many assumptions made by client-side connection pooling tools. In-memory SQLite is a great tool, but using it indirectly behind a connection pooler that assumes the database is external to the current process is bound to cause problems.
stmw
Agree with zbentley, I actually wouldn't expect this to work well - perhaps a good thing for sqlx team to warn against.
nbf_1995
SQLx and F# type-providers are probably the best developer experience for writing database access code. I wish more languages had something equivalent.
stmw
I think this sort of stuff only comes after a LOT of experience with building SQL db backed systems - it resonated with me immediately. (I'm the OP but not affiliated with this Rust project at all).
chuckhend
Love SQLx for my Rust projects. I would like to figure out a great way to use the compile time checks in python or js projects, but haven't explored it yet.
hyperbrainer
I have never used SQLx, but the best SQL integration I can think of is LINQ. How does this compare to that?
RonanSoleste
Different products. I would not compare them. LINQ is more like Diesel (https://diesel.rs/)
maxbond
To expand, SQLx isn't an ORM or query builder, what it does is allow you to write raw SQL with compile-time guarantees of type safety. It does this by connecting to a dev database at compile time & uses SQL's introspection features (specifically, by preparing a statement[1]) to analyze your queries. (It can also cache this information to check without a database available, and has a basic migration facility.)
[1] https://github.com/launchbadge/sqlx/blob/main/FAQ.md#how-do-...
S04dKHzrKT
In the dotnet world, SQLx is more analogous to F# type providers like FSharp.Data.SqlClient , SQLProvider or Rezoom.SQL.
OoooooooO
I've read the GitHub page but I still have no idea what problems it solves or why I should care about this library?
nbf_1995
It's a rust library that you can use to run sql queries against a database. It also inspects the database at compile* time to figure out the type of each column in your query so that your code is type-safe.
* Or in your editor as you're writing code.
I've been using sqlx with postgres for several months now on a production server with decent query volume all day long. It has been rock solid.
I find writing sql in rust with sqlx to be far fewer lines of code than the same in Go. This server was ported from Go and the end result was ~40% fewer lines of code, less memory usage and stable cpu/memory usage over time.