diff --git a/Makefile b/Makefile
index 4c521d4..1f1efe2 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-.PHONY: help fees match web web-py web-debug web-go go-build go-test go-test-all go-parity go-run go-lint capture-fixtures image run sync sync-2026 test test-v docs
+.PHONY: help fees match web web-py web-debug web-go go-build go-test go-test-all go-parity go-run go-sync-debug go-lint capture-fixtures image run sync sync-2026 test test-v docs
 
 export PYTHONPATH := scripts:$(PYTHONPATH)
 VENV := .venv
@@ -27,6 +27,7 @@ help:
 	@echo "  make go-parity   - Run Go parity tests (requires -tags=parity fixture corpus)"
 	@echo "  make go-test-all - Run both unit and parity tests"
 	@echo "  make go-lint     - Run golangci-lint on Go code"
+	@echo "  make go-sync-debug [DAYS=N] - Dry-run Go sync with Fio debug logs and txn table (default DAYS=30)"
 	@echo "  make capture-fixtures - Regenerate parity fixture corpus from live Python"
 	@echo "  make image       - Build Python OCI container image"
 	@echo "  make run         - Run the built Python Docker image locally"
@@ -91,6 +92,10 @@ capture-fixtures: $(PYTHON)
 go-run: go-build
 	./$(GO_BIN) $(ARGS)
 
+DAYS ?= 30
+go-sync-debug: go-build
+	LOG_LEVEL=DEBUG ./$(GO_BIN) sync -dry-run -print-fio-table -days $(DAYS)
+
 go-lint:
 	cd $(GO_SRC) && golangci-lint run ./...
 
diff --git a/docs/plans/2026-05-07-1321-fuj-sync-print-fio-table.md b/docs/plans/2026-05-07-1321-fuj-sync-print-fio-table.md
new file mode 100644
index 0000000..5f4dd53
--- /dev/null
+++ b/docs/plans/2026-05-07-1321-fuj-sync-print-fio-table.md
@@ -0,0 +1,29 @@
+# Add `--print-fio-table` debug flag to `fuj sync`
+
+## Context
+
+The Go port of `fuj sync --dry-run` currently prints only the **new**
+transactions — i.e. rows that will be appended to the payments sheet after
+deduping against existing Sync IDs (see [sync.go:125-129](../../go/internal/services/banksync/sync.go#L125-L129)).
+When debugging Fio sync issues ("why isn't transaction X showing up?",
+"is the dedup working?"), there's no way to see what Fio actually
+returned versus what got filtered as a duplicate.
+
+This change adds a `--print-fio-table` flag that, **only when combined
+with `--dry-run`**, prints an aligned table of every Fio transaction in
+the window with each row marked `NEW` (would be appended) or `DUP`
+(already in sheet, skipped). The flag is silently ignored without
+`--dry-run`, so it can't accidentally fire during a real sync.
+
+## Decisions
+
+- Flag name: `--print-fio-table` (specific, not generic `--verbose`).
+- Columns: `DATE | AMOUNT | SENDER | VS | MESSAGE | BANKID | STATUS`,
+  with MESSAGE truncated and STATUS = `NEW` / `DUP`.
+- Scope: only effective when `--dry-run` is also set.
+
+## Files modified
+
+- [go/cmd/fuj/main.go](../../go/cmd/fuj/main.go) — new flag + SyncOpts field
+- [go/internal/services/banksync/sync.go](../../go/internal/services/banksync/sync.go) — SyncOpts struct + refactored step 4
+- [go/internal/services/banksync/debug.go](../../go/internal/services/banksync/debug.go) — printFioTable helper (new)
diff --git a/go/cmd/fuj/main.go b/go/cmd/fuj/main.go
index ebe8d0d..dfa21a3 100644
--- a/go/cmd/fuj/main.go
+++ b/go/cmd/fuj/main.go
@@ -11,6 +11,7 @@ import (
 	"fuj-management/go/internal/services/banksync"
 	"fuj-management/go/internal/services/membership"
 	"fuj-management/go/internal/web"
+	"log/slog"
 	"os"
 	"time"
 )
@@ -28,6 +29,9 @@ func main() {
 		os.Exit(2)
 	}
 
+	// Honour LOG_LEVEL for slog calls in any package (e.g. internal/io/fio debug logs).
+	slog.SetDefault(logging.New(os.Getenv("LOG_LEVEL")))
+
 	cmd, args := os.Args[1], os.Args[2:]
 
 	switch cmd {
@@ -135,8 +139,9 @@ func syncCmd(args []string) {
 	toStr := fs.String("to", "", "end date YYYY-MM-DD")
 	sort := fs.Bool("sort", true, "sort sheet by date after appending")
 	dryRun := fs.Bool("dry-run", false, "print planned writes without modifying the sheet")
+	printFioTable := fs.Bool("print-fio-table", false, "with --dry-run: print aligned table of every Fio transaction with NEW/DUP status")
 	fs.Usage = func() {
-		fmt.Fprintln(os.Stderr, "usage: fuj sync [--days N] [--from YYYY-MM-DD --to YYYY-MM-DD] [--sort] [--dry-run]")
+		fmt.Fprintln(os.Stderr, "usage: fuj sync [--days N] [--from YYYY-MM-DD --to YYYY-MM-DD] [--sort] [--dry-run] [--print-fio-table]")
 		fs.PrintDefaults()
 	}
 	if err := fs.Parse(args); err != nil {
@@ -154,7 +159,7 @@ func syncCmd(args []string) {
 	}
 	fioCli := fio.New(cfg.FioAPIToken, config.IBANAccountNum(cfg.BankAccount), nil)
 
-	opts := banksync.SyncOpts{Days: *days, Sort: *sort, DryRun: *dryRun}
+	opts := banksync.SyncOpts{Days: *days, Sort: *sort, DryRun: *dryRun, PrintFioTable: *printFioTable}
 	if *fromStr != "" && *toStr != "" {
 		opts.From, err = time.Parse("2006-01-02", *fromStr)
 		if err != nil {
diff --git a/go/internal/io/fio/api.go b/go/internal/io/fio/api.go
index 26a8172..be32f91 100644
--- a/go/internal/io/fio/api.go
+++ b/go/internal/io/fio/api.go
@@ -5,7 +5,9 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
+	"strings"
 	"time"
 )
 
@@ -25,6 +27,9 @@ func (c *apiClient) FetchTransactions(ctx context.Context, from, to time.Time) (
 	const layout = "2006-01-02"
 	url := fmt.Sprintf("https://fioapi.fio.cz/v1/rest/periods/%s/%s/%s/transactions.json",
 		c.token, from.Format(layout), to.Format(layout))
+	slog.Debug("fio api: GET",
+		"url", strings.Replace(url, c.token, "****", 1),
+		"from", from.Format(layout), "to", to.Format(layout))
 
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
 	if err != nil {
@@ -35,6 +40,7 @@ func (c *apiClient) FetchTransactions(ctx context.Context, from, to time.Time) (
 		return nil, err
 	}
 	defer resp.Body.Close()
+	slog.Debug("fio api: response", "status", resp.StatusCode)
 	if resp.StatusCode != http.StatusOK {
 		return nil, fmt.Errorf("fio api: HTTP %d", resp.StatusCode)
 	}
@@ -42,7 +48,9 @@ func (c *apiClient) FetchTransactions(ctx context.Context, from, to time.Time) (
 	if err != nil {
 		return nil, err
 	}
-	return parseAPIResponse(body)
+	txns, err := parseAPIResponse(body)
+	slog.Debug("fio api: parsed", "body_bytes", len(body), "parsed_count", len(txns))
+	return txns, err
 }
 
 // fioAPIResponse is the top-level envelope from the Fio JSON API.
diff --git a/go/internal/io/fio/client.go b/go/internal/io/fio/client.go
index db40d54..2230ed5 100644
--- a/go/internal/io/fio/client.go
+++ b/go/internal/io/fio/client.go
@@ -4,6 +4,7 @@ package fio
 
 import (
 	"context"
+	"log/slog"
 	"net/http"
 	"time"
 )
@@ -36,7 +37,9 @@ func New(token, accountNum string, hc httpDoer) Client {
 		hc = http.DefaultClient
 	}
 	if token != "" {
+		slog.Debug("fio: client selected", "type", "api")
 		return &apiClient{token: token, hc: hc}
 	}
+	slog.Debug("fio: client selected", "type", "transparent", "account_num", accountNum)
 	return &transparentClient{accountNum: accountNum, hc: hc}
 }
diff --git a/go/internal/io/fio/fio_test.go b/go/internal/io/fio/fio_test.go
index 7a3e38c..84d0281 100644
--- a/go/internal/io/fio/fio_test.go
+++ b/go/internal/io/fio/fio_test.go
@@ -97,6 +97,9 @@ func TestParseCzechDate(t *testing.T) {
 		{"10/04/2026", "2026-04-10"},
 		{"7.5.2026", "2026-05-07"},  // non-padded — real Fio transparent page format
 		{"3.12.2025", "2025-12-03"}, // non-padded single-digit day, double-digit month
+		{"07.05.26", "2026-05-07"},  // padded 2-digit year — current Fio transparent page format
+		{"7.5.26", "2026-05-07"},   // non-padded 2-digit year
+		{"07/05/26", "2026-05-07"}, // slash variant
 		{"", ""},
 		{"invalid", ""},
 	}
diff --git a/go/internal/io/fio/transparent.go b/go/internal/io/fio/transparent.go
index 29ff7df..31184d7 100644
--- a/go/internal/io/fio/transparent.go
+++ b/go/internal/io/fio/transparent.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
 	"regexp"
 	"strings"
@@ -28,6 +29,10 @@ func (c *transparentClient) FetchTransactions(ctx context.Context, from, to time
 		from.Format("2.1.2006"),
 		to.Format("2.1.2006"),
 	)
+	slog.Debug("fio transparent: GET",
+		"url", url,
+		"from", from.Format("2006-01-02"), "to", to.Format("2006-01-02"))
+
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
 	if err != nil {
 		return nil, err
@@ -37,6 +42,7 @@ func (c *transparentClient) FetchTransactions(ctx context.Context, from, to time
 		return nil, err
 	}
 	defer resp.Body.Close()
+	slog.Debug("fio transparent: response", "status", resp.StatusCode)
 	if resp.StatusCode != http.StatusOK {
 		return nil, fmt.Errorf("fio transparent: HTTP %d", resp.StatusCode)
 	}
@@ -44,6 +50,7 @@ func (c *transparentClient) FetchTransactions(ctx context.Context, from, to time
 	if err != nil {
 		return nil, err
 	}
+	slog.Debug("fio transparent: body read", "body_bytes", len(body))
 	return parseTransparentHTML(body)
 }
 
@@ -63,6 +70,7 @@ func parseTransparentHTML(body []byte) ([]Transaction, error) {
 	rows := extractSecondTableRows(body)
 
 	var txns []Transaction
+	var droppedBadDate, droppedNonpositive int
 	for _, row := range rows {
 		col := func(i int) string {
 			if i < len(row) {
@@ -72,7 +80,12 @@ func parseTransparentHTML(body []byte) ([]Transaction, error) {
 		}
 		dateStr := parseCzechDate(col(tColDate))
 		amount := parseCzechAmount(col(tColAmount))
-		if dateStr == "" || amount <= 0 {
+		if dateStr == "" {
+			droppedBadDate++
+			continue
+		}
+		if amount <= 0 {
+			droppedNonpositive++
 			continue
 		}
 		txns = append(txns, Transaction{
@@ -86,6 +99,11 @@ func parseTransparentHTML(body []byte) ([]Transaction, error) {
 			BankID:  "", // not available on HTML path
 		})
 	}
+	slog.Debug("fio transparent: parsed",
+		"raw_rows", len(rows),
+		"kept", len(txns),
+		"dropped_bad_date", droppedBadDate,
+		"dropped_nonpositive_amount", droppedNonpositive)
 	return txns, nil
 }
 
@@ -191,7 +209,10 @@ func hasClass(t ghtml.Token, cls string) bool {
 // Returns "" on parse error.
 func parseCzechDate(s string) string {
 	s = strings.TrimSpace(s)
-	for _, layout := range []string{"2.1.2006", "02.01.2006", "2/1/2006", "02/01/2006"} {
+	for _, layout := range []string{
+		"2.1.2006", "02.01.2006", "2/1/2006", "02/01/2006",
+		"2.1.06", "02.01.06", "2/1/06", "02/01/06",
+	} {
 		if t, err := time.Parse(layout, s); err == nil {
 			return t.Format("2006-01-02")
 		}
diff --git a/go/internal/services/banksync/fio_table.go b/go/internal/services/banksync/fio_table.go
new file mode 100644
index 0000000..0fbb2e6
--- /dev/null
+++ b/go/internal/services/banksync/fio_table.go
@@ -0,0 +1,32 @@
+package banksync
+
+import (
+	"fmt"
+	"io"
+	"text/tabwriter"
+
+	"fuj-management/go/internal/io/fio"
+)
+
+func printFioTable(w io.Writer, txns []fio.Transaction, syncIDs []string, existing map[string]bool) {
+	tw := tabwriter.NewWriter(w, 0, 0, 2, ' ', 0)
+	fmt.Fprintln(tw, "DATE\tAMOUNT\tSENDER\tVS\tMESSAGE\tBANKID\tSTATUS")
+	for i, tx := range txns {
+		status := "NEW"
+		if existing[syncIDs[i]] {
+			status = "DUP"
+		}
+		fmt.Fprintf(tw, "%s\t%.2f\t%s\t%s\t%s\t%s\t%s\n",
+			tx.Date, tx.Amount, tx.Sender, tx.VS,
+			truncRunes(tx.Message, 40), tx.BankID, status)
+	}
+	_ = tw.Flush()
+}
+
+func truncRunes(s string, n int) string {
+	rs := []rune(s)
+	if len(rs) <= n {
+		return s
+	}
+	return string(rs[:n-1]) + "…"
+}
diff --git a/go/internal/services/banksync/sync.go b/go/internal/services/banksync/sync.go
index a036c2e..7a5fe6a 100644
--- a/go/internal/services/banksync/sync.go
+++ b/go/internal/services/banksync/sync.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"fuj-management/go/internal/domain/synch"
 	"fuj-management/go/internal/io/fio"
+	"os"
 	"strings"
 	"time"
 )
@@ -27,10 +28,11 @@ type sheetsWriter interface {
 
 // SyncOpts controls the date window and sort behaviour.
 type SyncOpts struct {
-	Days     int       // look-back window when From/To are zero
-	From, To time.Time // explicit window (overrides Days)
-	Sort     bool      // sort the sheet by Date after appending
-	DryRun   bool      // print planned writes without modifying the sheet
+	Days          int       // look-back window when From/To are zero
+	From, To      time.Time // explicit window (overrides Days)
+	Sort          bool      // sort the sheet by Date after appending
+	DryRun        bool      // print planned writes without modifying the sheet
+	PrintFioTable bool      // with DryRun: print every fetched Fio txn with NEW/DUP status
 }
 
 // SyncToSheets fetches Fio transactions and appends new ones to the payments sheet.
@@ -92,14 +94,14 @@ func SyncToSheets(
 			from.Format("2006-01-02"), to.Format("2006-01-02"), len(txns))
 	}
 
-	// 4. Append new rows.
-	var newRows [][]any
-	for _, tx := range txns {
+	// 4a. Compute Sync IDs for every fetched txn (shared by table-print and row-build).
+	syncIDs := make([]string, len(txns))
+	for i, tx := range txns {
 		currency := tx.Currency
 		if currency == "" {
 			currency = "CZK"
 		}
-		id := synch.GenerateSyncID(synch.Transaction{
+		syncIDs[i] = synch.GenerateSyncID(synch.Transaction{
 			Date:     tx.Date,
 			Amount:   tx.Amount,
 			Currency: currency,
@@ -108,13 +110,23 @@ func SyncToSheets(
 			Message:  tx.Message,
 			BankID:   tx.BankID,
 		})
-		if existingIDs[id] {
+	}
+
+	// 4b. Optional debug table (dry-run only; suppress when nothing was fetched).
+	if opts.DryRun && opts.PrintFioTable && len(txns) > 0 {
+		printFioTable(os.Stdout, txns, syncIDs, existingIDs)
+	}
+
+	// 4c. Build new rows.
+	var newRows [][]any
+	for i, tx := range txns {
+		if existingIDs[syncIDs[i]] {
 			continue
 		}
 		newRows = append(newRows, []any{
 			tx.Date, tx.Amount,
 			"", "", "", "", // manual fix, Person, Purpose, Inferred Amount
-			tx.Sender, tx.VS, tx.Message, tx.BankID, id,
+			tx.Sender, tx.VS, tx.Message, tx.BankID, syncIDs[i],
 		})
 	}