SQL Injection Checker

Paste a snippet that builds a SQL query and this checker flags the patterns that make SQL injection possible — f-strings, template literals, string concatenation, fmt.Sprintf and interpolated command text — then shows the parameterized version for your language. It is a heuristic static check, not a full parser, so treat it as a fast review aid rather than proof of safety. Your code never leaves the browser.

Language / driver

Your code

1 risk found

Line 2 · high · python-fstring
sql = f"SELECT id, email FROM users WHERE status = '{status}' AND age > {min_age}"
f-string interpolation inside a SQL literal. The value is pasted straight into the statement.

Parameterized rewrite

# line 2 — parameterized
sql = f"SELECT id, email FROM users WHERE status = '%s' AND age > %s"
# params: status, min_age

Safe pattern — Python (psycopg / sqlite3)

cur.execute(
    "SELECT id, email FROM users WHERE status = %s AND age > %s",
    (status, min_age),
)

# psycopg and MySQLdb use %s placeholders; sqlite3 uses ?. Never build the string with f-strings, % formatting or .format().

The rewrite is a starting point: check the placeholder style matches your driver, and remember that identifiers such as table and column names cannot be bound and must be validated against an allow-list instead.

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How to use

Pick the language and driver you use.
Paste the code that builds your SQL query.
Review each flagged line and copy the parameterized rewrite.

Frequently asked questions

How does this tool detect SQL injection?

It scans line by line for two things at once: SQL keywords such as SELECT, INSERT, UPDATE or WHERE, and a language-specific construct that splices a value into that text — an f-string, a template literal with ${}, string concatenation, fmt.Sprintf, PHP double-quoted interpolation or a C# interpolated string. A line that matches both is where injection happens. It is a heuristic, so it can miss queries assembled across several lines and can flag safe code that builds SQL from constants.

Is escaping user input enough to stop SQL injection?

No. Escaping depends on getting the quoting, character set and context exactly right every time, and it does nothing for values that are not quoted at all, such as a numeric comparison or a LIMIT. Prepared statements with bound parameters send the query text and the values on separate paths, so the value can never be reinterpreted as SQL. Use parameters everywhere, and allow-list identifiers such as table or column names, which cannot be bound.

How do I parameterize a dynamic ORDER BY or table name?

You cannot bind identifiers, only values. Keep a hard-coded map of the columns a user may sort by and look the input up in that map, rejecting anything not found — the query then only ever contains strings you wrote. In PostgreSQL you can also use format() with the %I identifier specifier inside a function. When you need to review the SQL an application actually sends, an AI SQL client such as Chat2DB can explain a query and its execution plan before you ship the fix.