typesqlType-level Postgres SQL for TypeScript

Write SQL as a string literal. The compiler parses it and gives you the row type, the parameter types and the schema changes. No codegen, no database connection, no build step.

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API reference

Exact row types

Column names follow Postgres's own naming rules, and nullability follows its semantics, including outer joins, aggregates, COALESCE, scalar subqueries and WHERE clauses that rule out NULL.

Typed parameters

$1, :name or inline ${sql.param(value)}. Each parameter takes its type from where it is used, and values are checked against it. Interpolating a value into the SQL text is a compile error.

Mistakes are compile errors

Unknown columns, ambiguous references, missing NOT NULL columns or syntax errors show up on the SQL string, worded like Postgres errors, with "Perhaps you meant" hints.

The whole statement language

Joins, subqueries, CTEs, set operations, window functions, INSERT/UPDATE/DELETE with RETURNING, ON CONFLICT, and DDL that evolves the schema type.

Thin runtime

A query is { text, values }. Adapters for node-postgres and postgres.js run it, with type maps that match each driver's parsers.

Built for TypeScript 7

The engine is written to the native compiler's recursion budgets: 100 simple queries in a file check in under a second, and statements up to 8 KB infer.

import { Pool } from "pg";
import { createSql, query } from "@typesql/pg";
import type { DB } from "./schema.js";

const sql = createSql<DB>();
const pool = new Pool({ connectionString: process.env["DATABASE_URL"] });

const recent = 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 > $1`,
  new Date("2026-01-01"),
);

const rows = await query(pool, recent);
// rows: { id: number; email: string; title: string | null }[]