TypeSQL vs Reylo

Reylo lets TypeScript import .sql files and types them from a live database. Like TypeSQL, it has no generated files and needs TypeScript 7.1: it runs as a content mapper that the compiler calls for each .sql import. To type a query, it prepares the statement on your development database (PostgreSQL, MySQL) or reads the database file (SQLite).

The same query

With Reylo, in recent_posts.sql:

select u.id, u.email, p.title
from users u
left join posts p on p.author_id = u.id
where u.created_at > :since

import recentPosts from "./recent_posts.sql";

const rows = await recentPosts.run(db, { since: new Date("2026-01-01") });

With TypeSQL, the SQL stays next to the code that runs it:

const rows = await sql(
	`select u.id, u.email, p.title
   from users u
   left join posts p on p.author_id = u.id
   where u.created_at > ${sql.param(new Date("2026-01-01"))}`,
).execute();

How they differ

	Reylo	TypeSQL
You write	SQL in .sql files, imported from TypeScript	SQL strings in TypeScript
Types come from	a live development database, through a content mapper	the TypeScript compiler, reading your schema type
Type checking needs	a running database, and tsc --runExternalCode	tsc
Running queries	a preload (--import reylo/register) or bundler plugin, with the engine installed at runtime	sql() builds { text, values }, and your driver sends it
Dynamic queries	CASE on parameters, and JSON parameters described by a JSON Schema	fragments
Migrations	applied with your own tool	applied with your own tool, or written as DDL that the schema type follows
Databases	PostgreSQL, MySQL, SQLite, DuckDB (preview)	PostgreSQL and SQLite; MySQL is planned

Both work out nullability from outer joins and from WHERE conditions that reject NULL.

Choose Reylo when

• You use MySQL or DuckDB.
• You want your SQL in .sql files.
• You want database errors typed, with .try() returning { value } or { error }.
• You'd rather check queries against the real database than keep a schema type in sync with it.

Choose TypeSQL when

• You want SQL next to the code that runs it, not in a separate file.
• You want to type-check in the editor and CI without a database running.
• You don't want a preload or bundler plugin to run your app, or the engine installed in production.
• Some queries are built from pieces at runtime.