diff --git a/docs/reference/http-api.md b/docs/reference/http-api.md
index e9469db1..0a680ac5 100644
--- a/docs/reference/http-api.md
+++ b/docs/reference/http-api.md
@@ -174,7 +174,7 @@ about the endpoint's rollout status on upstream clusters.
 | Method & path | Scope | Notes |
 |---|---|---|
 | `POST /repos` | repo:write (repo=new id) | Optional body `{repo_name?, default_branch?, upstream?, base_repo?}` (details below). → `{repo_id, repo_name, http_url, message}`. **201** = created; 200 = the name holds a finished repo the request matches; 409 = another live repo holds the name; 404 = a deleted repo holds the name; 503 = a create of the name is not finished (below). |
-| `GET /repos` | org:read (repo="org" or no repo) | Query `cursor, limit, q, prefix`. `q` is a case-insensitive substring of repo `url`, and `prefix` a case-insensitive start of it, both trimmed (empty = no filter). With `prefix` set, `q` matches only the rest of `url` after the prefix: `prefix=pierre/&q=sdk` returns `pierre/sdk-documentation`, not `pierre/example`. → `{repos: [{repo_id, repo_name, url (deprecated mirror), default_branch, created_at, upstream?, base_repo?}], next_cursor, has_more}` |
+| `GET /repos` | org:read (repo="org" or no repo) | Query `cursor, limit, q, prefix`. `q` is a case-insensitive substring of repo `url`, and `prefix` a case-insensitive start of it, both trimmed (empty = no filter). With `prefix` set, `q` matches only the rest of `url` after the prefix: `prefix=pierre/&q=sdk` returns `pierre/sdk-documentation`, not `pierre/example`. A `q` or `prefix` with a NUL byte or invalid UTF-8 is a 400. → `{repos: [{repo_id, repo_name, url (deprecated mirror), default_branch, created_at, upstream?, base_repo?}], next_cursor, has_more}` |
 | `GET /repo` | git:read (repo from JWT) | → `{repo_id, repo_name, url (deprecated mirror), default_branch, created_at, upstream?, base_repo?}`; 404 → SDK returns null |
 | `PATCH /repo` | repo:write | Update the default branch; body `{default_branch}` (details below). → `{repo_id, id (deprecated mirror), repo_name, url (deprecated mirror), default_branch}` (no `created_at`, per the live spec) |
 | `DELETE /repos/delete` | repo:write | Soft delete + async cleanup. → `{repo_name, repo_id (deprecated mirror), message}`; 404 not found; 409 already deleted |
diff --git a/internal/api/api_integration_test.go b/internal/api/api_integration_test.go
index dc1b704b..6ec4008a 100644
--- a/internal/api/api_integration_test.go
+++ b/internal/api/api_integration_test.go
@@ -690,6 +690,46 @@ func testListPrefix(t *testing.T, e *testEnv) {
 	}
 }
 
+// TestListFilterValues pins q and prefix values that no repo_name holds:
+// a value of 200 KiB lists no repo (SQLite refuses a LIKE pattern over
+// 50,000 bytes), and a NUL byte or invalid UTF-8, which PostgreSQL refuses
+// in a text parameter, is the client's 400.
+func TestListFilterValues(t *testing.T) { runBackends(t, testListFilterValues) }
+
+func testListFilterValues(t *testing.T, e *testEnv) {
+	org := e.newOrg(t)
+	createRepo(t, e, org, "acme/alpha", nil, http.StatusCreated)
+	orgTok := e.mint(t, tokenSpec{iss: org, repo: auth.RepoClaimOrg, scopes: []string{auth.ScopeOrgRead}})
+	long := strings.Repeat("a", 200<<10)
+	for _, tc := range []struct {
+		name   string
+		params url.Values
+		status int
+	}{
+		{"q of 200 KiB", url.Values{"q": {long}}, http.StatusOK},
+		{"prefix of 200 KiB", url.Values{"prefix": {long}}, http.StatusOK},
+		{"q of 25,001 percent signs", url.Values{"q": {strings.Repeat("%", 25_001)}}, http.StatusOK},
+		{"q with a NUL byte", url.Values{"q": {"a\x00b"}}, http.StatusBadRequest},
+		{"prefix with a NUL byte", url.Values{"prefix": {"acme\x00"}}, http.StatusBadRequest},
+		{"q not UTF-8", url.Values{"q": {"a\xffb"}}, http.StatusBadRequest},
+		{"prefix not UTF-8", url.Values{"prefix": {"\xff"}}, http.StatusBadRequest},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			resp, body := e.doReq(t, http.MethodGet, "/api/v1/repos?"+tc.params.Encode(), orgTok, nil, "")
+			if resp.StatusCode != tc.status {
+				t.Fatalf("status = %d (body %.300s), want %d", resp.StatusCode, body, tc.status)
+			}
+			if tc.status != http.StatusOK {
+				return
+			}
+			var page listReposResponse
+			if err := json.Unmarshal(body, &page); err != nil || len(page.Repos) != 0 || page.HasMore {
+				t.Fatalf("body %.300s (err %v), want an empty last page", body, err)
+			}
+		})
+	}
+}
+
 // TestAuthMatrix drives the docs/reference/http-api.md 401/403 failure map across the
 // repo lifecycle endpoints (create and list on both path styles), asserting status,
 // envelope shape, and WWW-Authenticate on 401.
diff --git a/internal/api/handlers.go b/internal/api/handlers.go
index 22582d2f..0b63fbd1 100644
--- a/internal/api/handlers.go
+++ b/internal/api/handlers.go
@@ -13,6 +13,7 @@ import (
 	"strconv"
 	"strings"
 	"time"
+	"unicode/utf8"
 
 	"github.com/coder/openstorage/internal/auth"
 	"github.com/coder/openstorage/internal/blob"
@@ -637,9 +638,16 @@ func (s *server) handleListRepos(w http.ResponseWriter, r *http.Request) {
 		limit = n
 	}
 
+	q, prefix := strings.TrimSpace(query.Get("q")), strings.TrimSpace(query.Get("prefix"))
+	for _, f := range []struct{ name, value string }{{"q", q}, {"prefix", prefix}} {
+		if !utf8.ValidString(f.value) || strings.ContainsRune(f.value, 0) {
+			writeErr(w, http.StatusBadRequest, "invalid "+f.name+" (want UTF-8 text without NUL)")
+			return
+		}
+	}
 	res, err := s.store.ListRepos(r.Context(), claims.Iss, meta.ListParams{
-		Q:      strings.TrimSpace(query.Get("q")),
-		Prefix: strings.TrimSpace(query.Get("prefix")),
+		Q:      q,
+		Prefix: prefix,
 		Cursor: query.Get("cursor"),
 		Limit:  limit,
 	})
diff --git a/internal/meta/meta.go b/internal/meta/meta.go
index 51104f91..c1deb4d6 100644
--- a/internal/meta/meta.go
+++ b/internal/meta/meta.go
@@ -13,7 +13,9 @@ import (
 	"fmt"
 	"log/slog"
 	"net/url"
+	"strings"
 	"time"
+	"unicode/utf8"
 )
 
 // Sentinel errors implementations must return (possibly wrapped; callers
@@ -114,12 +116,23 @@ const (
 // value here (default 20, max 100); the opaque cursor is validated by the
 // store (ErrInvalidCursor).
 type ListParams struct {
-	Q      string // case-insensitive substring filter on URL, pre-trimmed; "" = no filter; with Prefix set, only the URL after the prefix
-	Prefix string // case-insensitive filter on the start of URL, pre-trimmed; "" = no filter
+	Q      string // case-insensitive substring filter on URL, pre-trimmed UTF-8 without NUL; "" = no filter; with Prefix set, only the URL after the prefix
+	Prefix string // case-insensitive filter on the start of URL, pre-trimmed UTF-8 without NUL; "" = no filter
 	Cursor string // opaque cursor from a previous ListResult; "" = first page
 	Limit  int    // page size, already clamped/validated by the caller
 }
 
+// assertListFilters checks the ListParams filter contract. PostgreSQL
+// refuses a NUL byte and invalid UTF-8 in a text parameter (SQLSTATE
+// 22021), so the API refuses them first, and every backend gets the same
+// filters.
+func assertListFilters(p ListParams) {
+	for _, v := range []string{p.Q, p.Prefix} {
+		assertf(v == strings.TrimSpace(v) && utf8.ValidString(v) && !strings.ContainsRune(v, 0),
+			"ListRepos: filter %.80q is untrimmed, not UTF-8, or holds a NUL byte", v)
+	}
+}
+
 // ListResult is one page of repos ordered by (created_at DESC, repo_id DESC).
 type ListResult struct {
 	Repos      []Repo // never nil; empty slice when no matches
diff --git a/internal/meta/pg.go b/internal/meta/pg.go
index 08ae7ffa..e5bb24de 100644
--- a/internal/meta/pg.go
+++ b/internal/meta/pg.go
@@ -615,8 +615,7 @@ func escapeLike(s string) string {
 // prefix at the start, which consumes exactly the prefix's characters, so q
 // can only match the rest of the url after it.
 func listURLPattern(p ListParams) string {
-	assertf(p.Q == strings.TrimSpace(p.Q) && p.Prefix == strings.TrimSpace(p.Prefix),
-		"ListRepos: untrimmed filters q=%q prefix=%q", p.Q, p.Prefix)
+	assertListFilters(p)
 	if p.Q == "" && p.Prefix == "" {
 		return ""
 	}
diff --git a/internal/meta/pg_test.go b/internal/meta/pg_test.go
index 2c7a0f29..7c914abf 100644
--- a/internal/meta/pg_test.go
+++ b/internal/meta/pg_test.go
@@ -625,6 +625,10 @@ func testListReposQFilter(t *testing.T, s Backend) {
 	if got := urls(all); !slices.Equal(got, []string{"github.com/acme/Alpha", "github.com/acme/beta-ALPHA"}) {
 		t.Errorf("q=alpha -> %v", got)
 	}
+	all, _ = listAll(t, s, org, "GAMMA", 10) // q in another case than the url
+	if got := urls(all); !slices.Equal(got, []string{"github.com/acme/gamma"}) {
+		t.Errorf("q=GAMMA -> %v, want the gamma url", got)
+	}
 
 	// LIKE metacharacters in q are literals, not wildcards.
 	all, _ = listAll(t, s, org, "%", 10)
@@ -664,6 +668,7 @@ func testListReposPrefixFilter(t *testing.T, s Backend) {
 		"Pierre/Upper-SDK",
 		"pierre/pierre-mirror",
 		"acme/pierre-tools",
+		"acme/pierre/inner", // holds the prefix 'pierre/', but not at the start
 		"50%/off",
 		"500/decoy", // matches prefix '50%' only if % is unescaped
 		"a_b/one",
@@ -722,6 +727,48 @@ func testListReposPrefixFilter(t *testing.T, s Backend) {
 	}
 }
 
+func TestListReposLongFilters(t *testing.T) { runBackends(t, testListReposLongFilters) }
+
+// testListReposLongFilters pins q and prefix of any length: SQLite refuses
+// a LIKE pattern over 50,000 bytes (SQLITE_MAX_LIKE_PATTERN_LENGTH), and
+// an escaped `%` takes two of them.
+func testListReposLongFilters(t *testing.T, s Backend) {
+	ctx := t.Context()
+	org := seedOrg(t, s)
+	percents := strings.Repeat("%", 30_000)
+	long := "acme/" + percents + "/end"
+	for _, url := range []string{"acme/alpha", long} {
+		if _, err := s.CreateRepo(ctx, org, url, "main"); err != nil {
+			t.Fatalf("create %.40s: %v", url, err)
+		}
+	}
+	for _, tc := range []struct {
+		name, prefix, q string
+		want            []string
+	}{
+		{"q of 200 KiB", "", strings.Repeat("a", 200<<10), nil},
+		{"prefix of 200 KiB", strings.Repeat("a", 200<<10), "", nil},
+		{"q of 30,000 percent signs", "", percents, []string{long}},
+		{"q one percent sign longer", "", percents + "%", nil},
+		{"prefix of 30,000 percent signs and q", "acme/" + percents, "END", []string{long}},
+		{"q inside a long prefix", "acme/" + percents, "%", nil},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			res, err := s.ListRepos(ctx, org, ListParams{Q: tc.q, Prefix: tc.prefix, Limit: 10})
+			if err != nil {
+				t.Fatalf("list: %.300v", err)
+			}
+			got := make([]string, 0, len(res.Repos))
+			for _, r := range res.Repos {
+				got = append(got, r.URL)
+			}
+			if !slices.Equal(got, tc.want) {
+				t.Errorf("prefix %d bytes, q %d bytes: got %d repos, want %d", len(tc.prefix), len(tc.q), len(got), len(tc.want))
+			}
+		})
+	}
+}
+
 func TestListReposErrors(t *testing.T) { runBackends(t, testListReposErrors) }
 
 func testListReposErrors(t *testing.T, s Backend) {
diff --git a/internal/meta/s3walmeta.go b/internal/meta/s3walmeta.go
index d7524695..dd732fc9 100644
--- a/internal/meta/s3walmeta.go
+++ b/internal/meta/s3walmeta.go
@@ -1415,8 +1415,7 @@ func (s *S3WAL) ListRepos(ctx context.Context, org string, params ListParams) (L
 		}
 		cursorNanos, cursorID = createdAt.UnixNano(), repoID
 	}
-	assertf(params.Q == strings.TrimSpace(params.Q) && params.Prefix == strings.TrimSpace(params.Prefix),
-		"ListRepos: untrimmed filters q=%q prefix=%q", params.Q, params.Prefix)
+	assertListFilters(params)
 	q, prefix := strings.ToLower(params.Q), strings.ToLower(params.Prefix)
 	rows := make([]Repo, 0, params.Limit+1)
 	for id, r := range doc.Repos {
diff --git a/internal/meta/s3walmeta_test.go b/internal/meta/s3walmeta_test.go
index c2270796..174fec5a 100644
--- a/internal/meta/s3walmeta_test.go
+++ b/internal/meta/s3walmeta_test.go
@@ -462,6 +462,7 @@ func TestS3WALMetaConformance(t *testing.T) {
 		{"ListReposPagination", testListReposPagination},
 		{"ListReposQFilter", testListReposQFilter},
 		{"ListReposPrefixFilter", testListReposPrefixFilter},
+		{"ListReposLongFilters", testListReposLongFilters},
 		{"ListReposErrors", testListReposErrors},
 		{"Webhooks", testWebhooks},
 		{"GitCredentials", testGitCredentials},
diff --git a/internal/meta/sqlite.go b/internal/meta/sqlite.go
index a9c93f8b..e85780fc 100644
--- a/internal/meta/sqlite.go
+++ b/internal/meta/sqlite.go
@@ -724,7 +724,9 @@ func (s *SQLite) RemoveSigningKey(ctx context.Context, org string, id int64) err
 // ListRepos pages live repos for the org, keyset-ordered by
 // (created_at DESC, repo_id DESC).
 //
-// PG's `url ILIKE ?` becomes `lower(url) LIKE lower(?) ESCAPE '\'`. SQLite's
+// PG's `url ILIKE ?` becomes a start and a substring test of lower(url),
+// not LIKE: SQLite refuses a LIKE pattern over 50,000 bytes
+// (SQLITE_MAX_LIKE_PATTERN_LENGTH), and q and prefix can be longer. SQLite's
 // lower() only folds ASCII, so non-ASCII urls match case-sensitively here
 // while PG ILIKE folds per locale — an accepted divergence for local mode.
 func (s *SQLite) ListRepos(ctx context.Context, org string, params ListParams) (ListResult, error) {
@@ -739,9 +741,15 @@ func (s *SQLite) ListRepos(ctx context.Context, org string, params ListParams) (
 
 	query := `SELECT ` + repoCols + ` FROM repos WHERE org_id = ? AND deleted_at IS NULL`
 	args := []any{orgID}
-	if pattern := listURLPattern(params); pattern != "" {
-		args = append(args, pattern)
-		query += ` AND lower(url) LIKE lower(?) ESCAPE '\'`
+	assertListFilters(params)
+	if params.Prefix != "" {
+		args = append(args, params.Prefix, params.Prefix)
+		query += ` AND substr(lower(url), 1, length(?)) = lower(?)`
+	}
+	if params.Q != "" {
+		// With a prefix, q matches only the rest of the url after it.
+		args = append(args, params.Prefix, params.Q)
+		query += ` AND instr(substr(lower(url), length(?) + 1), lower(?)) > 0`
 	}
 	if params.Cursor != "" {
 		createdAt, repoID, err := decodeCursor(params.Cursor)