diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..485dee6
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+.idea
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..7d88c1b
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,9 @@
+test:
+	rm -rf kong
+	git clone https://github.com/Kong/kong.git
+	rm -f 1.0.0.md
+	echo "# 1.0.0" > 1.0.0.md
+	# use CHANGELOG/unreleased/kong to generate Kong system changelog
+	go build && ./changelog generate --repo Kong/kong --repo_path kong --changelog_path CHANGELOG/unreleased/kong --system Kong >> 1.0.0.md
+	# use CHANGELOG/unreleased/kong to generate Kong-enterprise system changelog
+	go build && ./changelog generate --repo Kong/kong --repo_path kong --changelog_path CHANGELOG/unreleased/kong --system Kong-enterprise >> 1.0.0.md
diff --git a/changelog-markdown.tmpl b/changelog-markdown.tmpl
new file mode 100644
index 0000000..3b8f04f
--- /dev/null
+++ b/changelog-markdown.tmpl
@@ -0,0 +1,28 @@
+{{- /* ===== entry template ==== */ -}}
+{{ define "entry" }}
+- {{ $.Message }}
+{{ range $i, $github := $.ParsedGithubs }} [{{ $github.Name }}]({{ $github.Link }}) {{ end }}
+{{ range $i, $jira := $.ParsedJiras }} [{{ $jira.ID }}]({{ $jira.Link }}) {{ end }}
+{{- end }}
+{{- /* ===== entry template ==== */ -}}
+{{- /* ==== section template ==== */ -}}
+{{ define "section"  }}
+{{- if .scopes }}
+{{- $length := len .scopes }}
+{{- if gt $length 0 }}
+### {{ .sectionName }}
+{{ range $i, $scope := .scopes }}
+#### {{ $scope.ScopeName }}
+{{ range $j, $entry := $scope.Entries }} {{ template "entry" $entry }} {{ end }}
+{{ end }}
+{{- end }}
+{{- end }}
+{{- end }}
+{{- /* ==== section template ==== */ -}}
+## {{ .System }}
+{{ template "section" (dict "sectionName" "Performance" "scopes" .Type.performance) }}
+{{ template "section" (dict "sectionName" "Breaking Changes" "scopes" .Type.breaking_change ) }}
+{{ template "section" (dict "sectionName" "Deprecations" "scopes" .Type.deprecation ) }}
+{{ template "section" (dict "sectionName" "Dependencies" "scopes" .Type.dependency ) }}
+{{ template "section" (dict "sectionName" "Features" "scopes" .Type.feature ) }}
+{{ template "section" (dict "sectionName" "Fixes" "scopes" .Type.bugfix ) }}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..5653d35
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,14 @@
+module konghq.com/changelog
+
+go 1.20
+
+require (
+	github.com/urfave/cli/v2 v2.25.7
+	gopkg.in/yaml.v3 v3.0.1
+)
+
+require (
+	github.com/cpuguy83/go-md2man/v2 v2.0.2 // indirect
+	github.com/russross/blackfriday/v2 v2.1.0 // indirect
+	github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 // indirect
+)
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..274e742
--- /dev/null
+++ b/main.go
@@ -0,0 +1,403 @@
+package main
+
+import (
+    "encoding/json"
+    "errors"
+    "fmt"
+    "github.com/urfave/cli/v2"
+    "gopkg.in/yaml.v3"
+    "io"
+    "log"
+    "net/http"
+    "os"
+    "path/filepath"
+    "regexp"
+    "sort"
+    "strings"
+    "text/template"
+)
+
+const (
+    JiraBaseUrl = "https://konghq.atlassian.net/browse/"
+)
+
+var (
+    ScopePriority = map[string]int{
+        "Performance":   10,
+        "Configuration": 20,
+        "Core":          30,
+        "PDK":           40,
+        "Plugin":        50,
+        "Admin API":     60,
+        "Clustering":    70,
+        "Default":       100, // default priority
+    }
+    repoPath      string
+    changelogPath string
+    system        string
+    repo          string
+    token         string
+)
+
+type CommitCtx struct {
+    SHA     string
+    Message string
+}
+
+type PullCtx struct {
+    Number int
+    Title  string
+    Body   string
+}
+
+type CommitContext struct {
+    Commit  CommitCtx
+    PullCtx PullCtx
+}
+
+func isYAML(filename string) bool {
+    return strings.HasSuffix(filename, ".yaml") || strings.HasSuffix(filename, ".yml")
+}
+
+func fetchCommitContext(filename string) (*CommitContext, error) {
+    ctx := &CommitContext{}
+    //if true {
+    //	return ctx, nil
+    //}
+    filename = filepath.Join(changelogPath, filename)
+
+    client := &http.Client{}
+
+    req, err := http.NewRequest("GET", fmt.Sprintf("https://api.github.com/repos/%s/commits?path=%s", repo, filename), nil)
+    if len(token) > 0 {
+        req.Header.Add("Authorization", fmt.Sprintf("Bearer %s", token))
+    }
+    response, err := client.Do(req)
+    if err != nil {
+        return nil, fmt.Errorf("failed to fetch commits: %v", err)
+    }
+    defer response.Body.Close()
+    if response.StatusCode != 200 {
+        return nil, fmt.Errorf("failed to fetch commits: %d %s", response.StatusCode, response.Status)
+    }
+
+    bytes, err := io.ReadAll(response.Body)
+    if err != nil {
+        return nil, err
+    }
+
+    var res []map[string]interface{}
+    err = json.Unmarshal(bytes, &res)
+    if err != nil {
+        return nil, fmt.Errorf("failed unmarshal: %v", err)
+    }
+
+    ctx.Commit = CommitCtx{
+        SHA:     res[0]["sha"].(string),
+        Message: res[0]["commit"].(map[string]interface{})["message"].(string),
+    }
+
+    req, err = http.NewRequest("GET", fmt.Sprintf("https://api.github.com/repos/%s/commits/%s/pulls", repo, ctx.Commit.SHA), nil)
+    if len(token) > 0 {
+        req.Header.Add("Authorization", fmt.Sprintf("Bearer %s", token))
+    }
+    response, err = client.Do(req)
+    if err != nil {
+        return nil, fmt.Errorf("failed to fetch pulls: %v", err)
+    }
+    defer response.Body.Close()
+
+    if response.StatusCode != 200 {
+        return nil, fmt.Errorf("failed to fetch pulls: %d %s", response.StatusCode, response.Status)
+    }
+
+    bytes, err = io.ReadAll(response.Body)
+    if err != nil {
+        return nil, err
+    }
+    err = json.Unmarshal(bytes, &res)
+    if err != nil {
+        return nil, fmt.Errorf("failed unmarshal: %v", err)
+    }
+    ctx.PullCtx = PullCtx{
+        Number: int(res[len(res)-1]["number"].(float64)),
+        Title:  res[len(res)-1]["title"].(string),
+        Body:   res[len(res)-1]["body"].(string),
+    }
+
+    return ctx, nil
+}
+
+func matchPattern(text, pattern string, t *[]string) {
+    re := regexp.MustCompile(pattern)
+    matches := re.FindAllString(text, -1)
+    *t = append(*t, matches...)
+}
+
+type ScopeEntries struct {
+    ScopeName string
+    Entries   []*ChangelogEntry
+}
+
+type Data struct {
+    System string
+    Type   map[string][]ScopeEntries
+}
+
+type Jira struct {
+    ID   string
+    Link string
+}
+
+type Github struct {
+    Name string
+    Link string
+}
+
+type ChangelogEntry struct {
+    Message       string   `yaml:"message"`
+    Type          string   `yaml:"type"`
+    Scope         string   `yaml:"scope"`
+    Prs           []int    `yaml:"prs"`
+    Githubs       []int    `yaml:"githubs"`
+    Jiras         []string `yaml:"jiras"`
+    ParsedJiras   []*Jira
+    ParsedGithubs []*Github
+}
+
+func parseGithub(githubNos []int) []*Github {
+    list := make([]*Github, 0)
+    for _, no := range githubNos {
+        github := &Github{
+            Name: fmt.Sprintf("#%d", no),
+            Link: fmt.Sprintf("https://github.com/%s/issues/%d", repo, no),
+        }
+        list = append(list, github)
+    }
+    return list
+}
+
+func processEntry(filename string, entry *ChangelogEntry) error {
+    if entry.Scope == "" {
+        entry.Scope = "Default"
+    }
+
+    ctx, err := fetchCommitContext(filename)
+    if err != nil {
+        return fmt.Errorf("faield to fetch commit ctx: %v", err)
+    }
+
+    // jiras
+    if len(entry.Jiras) == 0 {
+        jiraMap := make(map[string]bool)
+        r := regexp.MustCompile(`[a-zA-Z]+-\d+`)
+        jiras := r.FindAllString(ctx.PullCtx.Body, -1)
+        for _, jira := range jiras {
+            if !jiraMap[jira] {
+                entry.Jiras = append(entry.Jiras, jira)
+                jiraMap[jira] = true
+            }
+        }
+    }
+    for _, jiraId := range entry.Jiras {
+        jira := Jira{
+            ID:   jiraId,
+            Link: JiraBaseUrl + jiraId,
+        }
+        entry.ParsedJiras = append(entry.ParsedJiras, &jira)
+    }
+
+    // githubs
+    if len(entry.Githubs) == 0 {
+        entry.Githubs = entry.Prs
+    }
+    if len(entry.Githubs) == 0 {
+        entry.Githubs = append(entry.Githubs, ctx.PullCtx.Number)
+    }
+
+    entry.ParsedGithubs = parseGithub(entry.Githubs)
+
+    return nil
+}
+
+func mapKeys(m map[string][]*ChangelogEntry) []string {
+    keys := make([]string, 0)
+    for k := range m {
+        keys = append(keys, k)
+    }
+    return keys
+}
+
+func collect() (*Data, error) {
+    path := filepath.Join(repoPath, changelogPath)
+    files, err := os.ReadDir(path)
+    if err != nil {
+        return nil, err
+    }
+
+    data := &Data{
+        System: system,
+        Type:   make(map[string][]ScopeEntries),
+    }
+
+    maps := make(map[string]map[string][]*ChangelogEntry)
+
+    for _, file := range files {
+        if file.IsDir() || !isYAML(file.Name()) {
+            continue
+        }
+        content, err := os.ReadFile(filepath.Join(path, file.Name()))
+        if err != nil {
+            return nil, err
+        }
+
+        // parse entry
+        entry := &ChangelogEntry{}
+        err = yaml.Unmarshal(content, entry)
+
+        if err != nil {
+            return nil, fmt.Errorf("failed to unmarshal YAML from %s: %v", file.Name(), err)
+        }
+
+        err = processEntry(file.Name(), entry)
+        if err != nil {
+            return nil, fmt.Errorf("fialed to process entry: %v", err)
+        }
+
+        if maps[entry.Type] == nil {
+            maps[entry.Type] = make(map[string][]*ChangelogEntry)
+        }
+        maps[entry.Type][entry.Scope] = append(maps[entry.Type][entry.Scope], entry)
+    }
+
+    data.Type = make(map[string][]ScopeEntries)
+    for t, scopeEntries := range maps {
+        scopes := mapKeys(scopeEntries)
+        sort.Slice(scopes, func(i, j int) bool {
+            scopei := scopes[i]
+            scopej := scopes[j]
+            return ScopePriority[scopei] < ScopePriority[scopej]
+        })
+
+        list := make([]ScopeEntries, 0)
+        for _, scope := range scopes {
+            entries := ScopeEntries{
+                ScopeName: scope,
+                Entries:   scopeEntries[scope],
+            }
+            list = append(list, entries)
+        }
+        data.Type[t] = list
+    }
+
+    //bytes, _ := json.Marshal(data)
+    //fmt.Println(string(bytes))
+
+    return data, nil
+}
+
+func generate(data *Data) (string, error) {
+    tmpl, err := template.New("changelog-markdown.tmpl").Funcs(template.FuncMap{
+        "arr": func(values ...any) []any { return values },
+        "dict": func(values ...any) (map[string]any, error) {
+            if len(values)%2 != 0 {
+                return nil, errors.New("invalid dictionary call")
+            }
+
+            root := make(map[string]any)
+
+            for i := 0; i < len(values); i += 2 {
+                dict := root
+                var key string
+                switch v := values[i].(type) {
+                case string:
+                    key = v
+                case []string:
+                    for i := 0; i < len(v)-1; i++ {
+                        key = v[i]
+                        var m map[string]any
+                        v, found := dict[key]
+                        if found {
+                            m = v.(map[string]any)
+                        } else {
+                            m = make(map[string]any)
+                            dict[key] = m
+                        }
+                        dict = m
+                    }
+                    key = v[len(v)-1]
+                default:
+                    return nil, errors.New("invalid dictionary key")
+                }
+                dict[key] = values[i+1]
+            }
+
+            return root, nil
+        },
+    }).ParseFiles("changelog-markdown.tmpl")
+    if err != nil {
+        panic(err)
+    }
+    err = tmpl.Execute(os.Stdout, data)
+    if err != nil {
+        panic(err)
+    }
+
+    return "", nil
+}
+
+func main() {
+    token = os.Getenv("GITHUB_TOKEN")
+
+    var app = cli.App{
+        Name:    "changelog",
+        Version: "1.0.0",
+        Commands: []*cli.Command{
+            // generate command
+            {
+                Name:  "generate",
+                Usage: "Generate changelog",
+                Flags: []cli.Flag{
+                    &cli.StringFlag{
+                        Name:     "changelog_path",
+                        Usage:    "The changelog path. (e.g. CHANGELOG/unreleased)",
+                        Required: true,
+                    },
+                    &cli.StringFlag{
+                        Name:     "system",
+                        Usage:    "The system name. (e.g. Kong)",
+                        Required: true,
+                    },
+                    &cli.StringFlag{
+                        Name:     "repo_path",
+                        Usage:    "The repository path. (e.g. /path/to/your/repository)",
+                        Required: true,
+                    },
+                    &cli.StringFlag{
+                        Name:     "repo",
+                        Usage:    "The repository name. (e.g. Kong/kong)",
+                        Required: true,
+                    },
+                },
+                Action: func(c *cli.Context) error {
+                    repoPath = c.String("repo_path")
+                    changelogPath = c.String("changelog_path")
+                    system = c.String("system")
+                    repo = c.String("repo")
+
+                    data, err := collect()
+                    if err != nil {
+                        return err
+                    }
+                    data.System = system
+                    changelog, err := generate(data)
+                    _ = changelog
+                    return err
+                },
+            },
+        },
+    }
+    if err := app.Run(os.Args); err != nil {
+        log.Fatal(err)
+    }
+}