diff --git a/tools/xlsxread/src/error.rs b/tools/xlsxread/src/error.rs
new file mode 100644
index 0000000..e15edc9
--- /dev/null
+++ b/tools/xlsxread/src/error.rs
@@ -0,0 +1,34 @@
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum BuildError {
+    #[error("I/O error for {path}: {source}")]
+    Io {
+        path: String,
+        #[source]
+        source: std::io::Error,
+    },
+
+    #[error("Calamine error for {path}: {source}")]
+    Calamine {
+        path: String,
+        #[source]
+        source: calamine::Error,
+    },
+
+    #[error("SQLite error: {0}")]
+    Sqlite(#[from] rusqlite::Error),
+
+    #[error("Config parse error: {0}")]
+    Config(#[from] toml::de::Error),
+
+    #[error("Regex compile error for pattern '{pattern}': {source}")]
+    Regex {
+        pattern: String,
+        #[source]
+        source: regex::Error,
+    },
+
+    #[error("Schema has no sheets in file: {0}")]
+    NoSheets(String),
+}
diff --git a/tools/xlsxread/src/reader.rs b/tools/xlsxread/src/reader.rs
new file mode 100644
index 0000000..ac71da1
--- /dev/null
+++ b/tools/xlsxread/src/reader.rs
@@ -0,0 +1,197 @@
+/// Spreadsheet reader: wraps calamine to iterate rows across sheets.
+///
+/// Sheet selection mirrors the JS scripts:
+///   - sheet_mode = "all"   → iterate every sheet (handles HCM/HN 65k overflow in data/)
+///   - sheet_mode = "first" → sheet 0 only (data-old/)
+///
+/// Header detection mirrors build-lib.js isHeaderRow:
+///   row[0].toUpperCase() in {"HO_TEN", "HỌ TÊN", "STT"}
+use std::path::Path;
+
+use calamine::{open_workbook_auto, Data, Reader, Sheets};
+
+use crate::config::{DatasetConfig, HeaderCfg, SheetMode};
+use crate::error::BuildError;
+
+// ---------------------------------------------------------------------------
+// Public row representation from calamine
+// ---------------------------------------------------------------------------
+
+pub type RawRow = Vec<Data>;
+
+// ---------------------------------------------------------------------------
+// Header detection — mirrors build-lib.js isHeaderRow
+// ---------------------------------------------------------------------------
+
+/// Returns true when the first cell (uppercased) matches one of the configured
+/// header tokens. Used to skip the header row on the first row of each sheet.
+pub fn is_header_row(row: &[Data], header_cfg: &HeaderCfg) -> bool {
+    if row.len() < 3 {
+        return false;
+    }
+    let first = row[0].to_string().trim().to_uppercase();
+    header_cfg.tokens.iter().any(|t| t.to_uppercase() == first)
+}
+
+// ---------------------------------------------------------------------------
+// All-blank row check (data-old2: strip_blank_rows)
+// ---------------------------------------------------------------------------
+
+pub fn is_all_blank(row: &[Data]) -> bool {
+    row.iter()
+        .all(|c| matches!(c, Data::Empty) || c.to_string().trim().is_empty())
+}
+
+// ---------------------------------------------------------------------------
+// File processor — yields all data rows from the file
+// ---------------------------------------------------------------------------
+
+/// Process one spreadsheet file, calling `on_row` for each data row.
+///
+/// `on_row` receives `(sheet_index, row_index_in_sheet, raw_row)` where
+/// `row_index_in_sheet` is 0-based AFTER the header has been consumed.
+/// Returns `(sheets_seen, total_rows_yielded)`.
+pub fn process_file<F>(
+    path: &Path,
+    cfg: &DatasetConfig,
+    mut on_row: F,
+) -> Result<(usize, usize), BuildError>
+where
+    F: FnMut(usize, &RawRow),
+{
+    let path_str = path.display().to_string();
+
+    // calamine::open_workbook_auto dispatches on file extension
+    let mut workbook: Sheets<_> = open_workbook_auto(path).map_err(|e| BuildError::Calamine {
+        path: path_str.clone(),
+        source: e,
+    })?;
+
+    let sheet_names: Vec<String> = workbook.sheet_names().to_vec();
+    if sheet_names.is_empty() {
+        return Err(BuildError::NoSheets(path_str.clone()));
+    }
+
+    // Sheet selection per config
+    let sheets_to_read: Vec<String> = match cfg.reader.sheet_mode {
+        SheetMode::All => sheet_names.clone(),
+        SheetMode::First => vec![sheet_names[0].clone()],
+    };
+
+    let mut total_rows = 0usize;
+
+    for (sheet_idx, sheet_name) in sheets_to_read.iter().enumerate() {
+        let range = workbook
+            .worksheet_range(sheet_name)
+            .map_err(|e| BuildError::Calamine {
+                path: path_str.clone(),
+                source: e,
+            })?;
+
+        let mut first_row = true;
+
+        for raw in range.rows() {
+            let row: RawRow = raw.to_vec();
+
+            // Skip header row on first row of each sheet (matches JS: `if (i === 0 && isHeaderRow(...))`)
+            if first_row {
+                first_row = false;
+                if is_header_row(&row, &cfg.header) {
+                    continue;
+                }
+            }
+
+            on_row(sheet_idx, &row);
+            total_rows += 1;
+        }
+    }
+
+    Ok((sheets_to_read.len(), total_rows))
+}
+
+// ---------------------------------------------------------------------------
+// Unit tests
+// ---------------------------------------------------------------------------
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::config::HeaderCfg;
+
+    fn hdr(tokens: &[&str]) -> HeaderCfg {
+        HeaderCfg {
+            tokens: tokens.iter().map(|s| s.to_string()).collect(),
+        }
+    }
+
+    #[test]
+    fn header_detects_ho_ten() {
+        let row = vec![
+            Data::String("HO_TEN".into()),
+            Data::String("NGAY_SINH".into()),
+            Data::String("SBD".into()),
+        ];
+        let cfg = hdr(&["HO_TEN", "HỌ TÊN", "STT"]);
+        assert!(is_header_row(&row, &cfg));
+    }
+
+    #[test]
+    fn header_detects_stt() {
+        let row = vec![
+            Data::String("STT".into()),
+            Data::String("B".into()),
+            Data::String("C".into()),
+        ];
+        let cfg = hdr(&["HO_TEN", "HỌ TÊN", "STT"]);
+        assert!(is_header_row(&row, &cfg));
+    }
+
+    #[test]
+    fn header_detects_ho_ten_unicode() {
+        let row = vec![
+            Data::String("HỌ TÊN".into()),
+            Data::String("B".into()),
+            Data::String("C".into()),
+        ];
+        let cfg = hdr(&["HO_TEN", "HỌ TÊN", "STT"]);
+        assert!(is_header_row(&row, &cfg));
+    }
+
+    #[test]
+    fn header_rejects_data_row() {
+        let row = vec![
+            Data::String("Nguyen Van A".into()),
+            Data::String("01/01/2000".into()),
+            Data::String("12345678".into()),
+        ];
+        let cfg = hdr(&["HO_TEN", "HỌ TÊN", "STT"]);
+        assert!(!is_header_row(&row, &cfg));
+    }
+
+    #[test]
+    fn header_rejects_short_row() {
+        let row = vec![Data::String("HO_TEN".into()), Data::Empty];
+        let cfg = hdr(&["HO_TEN", "HỌ TÊN", "STT"]);
+        assert!(!is_header_row(&row, &cfg));
+    }
+
+    #[test]
+    fn header_case_insensitive() {
+        let row = vec![
+            Data::String("ho_ten".into()),
+            Data::String("B".into()),
+            Data::String("C".into()),
+        ];
+        let cfg = hdr(&["HO_TEN", "HỌ TÊN", "STT"]);
+        assert!(is_header_row(&row, &cfg));
+    }
+
+    #[test]
+    fn blank_row_detection() {
+        let row = vec![Data::Empty, Data::Empty, Data::String("".into())];
+        assert!(is_all_blank(&row));
+
+        let row2 = vec![Data::String("Nguyen".into()), Data::Empty, Data::Empty];
+        assert!(!is_all_blank(&row2));
+    }
+}