diff --git a/go.mod b/go.mod
index 39b2212..81d7a8c 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,21 @@
 module gitea/json-adapter
 
 go 1.22.3
+
+require github.com/glebarez/sqlite v1.11.0
+
+require (
+	github.com/dustin/go-humanize v1.0.1 // indirect
+	github.com/glebarez/go-sqlite v1.21.2 // indirect
+	github.com/google/uuid v1.3.0 // indirect
+	github.com/jinzhu/inflection v1.0.0 // indirect
+	github.com/jinzhu/now v1.1.5 // indirect
+	github.com/mattn/go-isatty v0.0.17 // indirect
+	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
+	golang.org/x/sys v0.7.0 // indirect
+	gorm.io/gorm v1.25.7 // indirect
+	modernc.org/libc v1.22.5 // indirect
+	modernc.org/mathutil v1.5.0 // indirect
+	modernc.org/memory v1.5.0 // indirect
+	modernc.org/sqlite v1.23.1 // indirect
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..062a22e
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,32 @@
+github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
+github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
+github.com/glebarez/go-sqlite v1.21.2 h1:3a6LFC4sKahUunAmynQKLZceZCOzUthkRkEAl9gAXWo=
+github.com/glebarez/go-sqlite v1.21.2/go.mod h1:sfxdZyhQjTM2Wry3gVYWaW072Ri1WMdWJi0k6+3382k=
+github.com/glebarez/sqlite v1.11.0 h1:wSG0irqzP6VurnMEpFGer5Li19RpIRi2qvQz++w0GMw=
+github.com/glebarez/sqlite v1.11.0/go.mod h1:h8/o8j5wiAsqSPoWELDUdJXhjAhsVliSn7bWZjOhrgQ=
+github.com/google/pprof v0.0.0-20221118152302-e6195bd50e26 h1:Xim43kblpZXfIBQsbuBVKCudVG457BR2GZFIz3uw3hQ=
+github.com/google/pprof v0.0.0-20221118152302-e6195bd50e26/go.mod h1:dDKJzRmX4S37WGHujM7tX//fmj1uioxKzKxz3lo4HJo=
+github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/jinzhu/inflection v1.0.0 h1:K317FqzuhWc8YvSVlFMCCUb36O/S9MCKRDI7QkRKD/E=
+github.com/jinzhu/inflection v1.0.0/go.mod h1:h+uFLlag+Qp1Va5pdKtLDYj+kHp5pxUVkryuEj+Srlc=
+github.com/jinzhu/now v1.1.5 h1:/o9tlHleP7gOFmsnYNz3RGnqzefHA47wQpKrrdTIwXQ=
+github.com/jinzhu/now v1.1.5/go.mod h1:d3SSVoowX0Lcu0IBviAWJpolVfI5UJVZZ7cO71lE/z8=
+github.com/mattn/go-isatty v0.0.17 h1:BTarxUcIeDqL27Mc+vyvdWYSL28zpIhv3RoTdsLMPng=
+github.com/mattn/go-isatty v0.0.17/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+github.com/remyoudompheng/bigfft v0.0.0-20200410134404-eec4a21b6bb0/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
+github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
+github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
+golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.7.0 h1:3jlCCIQZPdOYu1h8BkNvLz8Kgwtae2cagcG/VamtZRU=
+golang.org/x/sys v0.7.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+gorm.io/gorm v1.25.7 h1:VsD6acwRjz2zFxGO50gPO6AkNs7KKnvfzUjHQhZDz/A=
+gorm.io/gorm v1.25.7/go.mod h1:hbnx/Oo0ChWMn1BIhpy1oYozzpM15i4YPuHDmfYtwg8=
+modernc.org/libc v1.22.5 h1:91BNch/e5B0uPbJFgqbxXuOnxBQjlS//icfQEGmvyjE=
+modernc.org/libc v1.22.5/go.mod h1:jj+Z7dTNX8fBScMVNRAYZ/jF91K8fdT2hYMThc3YjBY=
+modernc.org/mathutil v1.5.0 h1:rV0Ko/6SfM+8G+yKiyI830l3Wuz1zRutdslNoQ0kfiQ=
+modernc.org/mathutil v1.5.0/go.mod h1:mZW8CKdRPY1v87qxC/wUdX5O1qDzXMP5TH3wjfpga6E=
+modernc.org/memory v1.5.0 h1:N+/8c5rE6EqugZwHii4IFsaJ7MUhoWX07J5tC/iI5Ds=
+modernc.org/memory v1.5.0/go.mod h1:PkUhL0Mugw21sHPeskwZW4D6VscE/GQJOnIpCnW6pSU=
+modernc.org/sqlite v1.23.1 h1:nrSBg4aRQQwq59JpvGEQ15tNxoO5pX/kUjcRNwSAGQM=
+modernc.org/sqlite v1.23.1/go.mod h1:OrDj17Mggn6MhE+iPbBNf7RGKODDE9NFT0f3EwDzJqk=
diff --git a/main.go b/main.go
index 96d3fe0..6fb2972 100644
--- a/main.go
+++ b/main.go
@@ -2,6 +2,8 @@ package main
 
 import (
 	"bytes"
+	"context"
+	"database/sql"
 	"encoding/json"
 	"flag"
 	"io"
@@ -13,6 +15,8 @@ import (
 	"strings"
 	"text/template"
 	"time"
+
+	_ "github.com/glebarez/sqlite"
 )
 
 var httpc = &http.Client{
@@ -23,8 +27,9 @@ var httpc = &http.Client{
 }
 
 type Handler struct {
-	tmpl   *template.Template
-	target *url.URL
+	tmpl        *template.Template
+	target      *url.URL
+	idempotency *sql.DB
 }
 
 func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
@@ -54,10 +59,20 @@ func main() {
 	p := fs.Int("p", 28080, "port")
 	t := fs.String("t", "{{ . }}", "template")
 	y := fs.String("y", "http://localhost:41912", "target")
+	db := fs.String("db", "/tmp/json-adapter.db", "sqlite db for idempotency")
 	if err := fs.Parse(os.Args[1:]); err != nil {
 		panic(err)
 	}
 
+	db, err := sql.Open("sqlite", *db)
+	if err != nil {
+		panic(err)
+	}
+	defer db.Close()
+	if err := db.PingContext(context.Background()); err != nil {
+		panic(err)
+	}
+
 	tmpl, err := template.New("").Parse(*t)
 	if err != nil {
 		panic(err)
@@ -68,7 +83,7 @@ func main() {
 		panic(err)
 	}
 
-	h := Handler{tmpl: tmpl, target: u}
+	h := Handler{tmpl: tmpl, target: u, idempotency: db}
 	log.Println("listening on", *p)
 	if err := http.ListenAndServe(":"+strconv.Itoa(*p), h); err != nil {
 		panic(err)