diff --git a/.github/workflows/obitest.yml b/.github/workflows/obitest.yml
index b17be06..9d0f12a 100644
--- a/.github/workflows/obitest.yml
+++ b/.github/workflows/obitest.yml
@@ -10,10 +10,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Setup Go
-      uses: actions/setup-go@v2
+      uses: actions/setup-go@v5
       with:
         go-version: '1.23'
     - name: Checkout obitools4 project
-      uses: actions/checkout@v4
+      uses: actions/checkout@v5
     - name: Run tests
       run: make githubtests
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 6ffb05c..c8855d6 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -18,7 +18,7 @@ jobs:
         with:
           go-version: "1.26"
       - name: Checkout obitools4 project
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: Run tests
         run: make githubtests
 
@@ -49,7 +49,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
 
       - name: Setup Go
         uses: actions/setup-go@v5
@@ -107,7 +107,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           fetch-depth: 0
 
diff --git a/go.sum b/go.sum
index 43b4e10..f8938c3 100644
--- a/go.sum
+++ b/go.sum
@@ -6,8 +6,6 @@ github.com/PaesslerAG/jsonpath v0.1.0 h1:gADYeifvlqK3R3i2cR5B4DGgxLXIPb3TRTH1mGi
 github.com/PaesslerAG/jsonpath v0.1.0/go.mod h1:4BzmtoM/PI8fPO4aQGIusjGxGir2BzcV0grWtFzq1Y8=
 github.com/barkimedes/go-deepcopy v0.0.0-20220514131651-17c30cfc62df h1:GSoSVRLoBaFpOOds6QyY1L8AX7uoY+Ln3BHc22W40X0=
 github.com/barkimedes/go-deepcopy v0.0.0-20220514131651-17c30cfc62df/go.mod h1:hiVxq5OP2bUGBRNS3Z/bt/reCLFNbdcST6gISi1fiOM=
-github.com/buger/jsonparser v1.1.1 h1:2PnMjfWD7wBILjqQbt530v576A/cAbQvEW9gGIpYMUs=
-github.com/buger/jsonparser v1.1.1/go.mod h1:6RYKKt7H4d4+iWqouImQ9R2FZql3VbhNgx27UK13J/0=
 github.com/buger/jsonparser v1.1.2 h1:frqHqw7otoVbk5M8LlE/L7HTnIq2v9RX6EJ48i9AxJk=
 github.com/buger/jsonparser v1.1.2/go.mod h1:6RYKKt7H4d4+iWqouImQ9R2FZql3VbhNgx27UK13J/0=
 github.com/chen3feng/stl4go v0.1.1 h1:0L1+mDw7pomftKDruM23f1mA7miavOj6C6MZeadzN2Q=
diff --git a/pkg/obilua/luahttp.go b/pkg/obilua/luahttp.go
index 07d80e6..6120ae3 100644
--- a/pkg/obilua/luahttp.go
+++ b/pkg/obilua/luahttp.go
@@ -4,15 +4,33 @@ import (
 	"io"
 	"net/http"
 	"strings"
+	"sync"
 	"time"
 
+	"git.metabarcoding.org/obitools/obitools4/obitools4/pkg/obidefault"
 	lua "github.com/yuin/gopher-lua"
 )
 
 const httpClientTimeout = 30 * time.Second
 
-var _httpClient = &http.Client{
-	Timeout: httpClientTimeout,
+var (
+	_httpClient     *http.Client
+	_httpClientOnce sync.Once
+)
+
+func getHTTPClient() *http.Client {
+	_httpClientOnce.Do(func() {
+		conns := 2 * obidefault.ParallelWorkers()
+		_httpClient = &http.Client{
+			Transport: &http.Transport{
+				MaxIdleConnsPerHost: conns,
+				MaxConnsPerHost:     conns,
+				IdleConnTimeout:     90 * time.Second,
+			},
+			Timeout: httpClientTimeout,
+		}
+	})
+	return _httpClient
 }
 
 // RegisterHTTP registers the http module in the Lua state as a global,
@@ -46,7 +64,7 @@ func luaHTTPPost(L *lua.LState) int {
 	}
 	req.Header.Set("Content-Type", "application/json")
 
-	resp, err := _httpClient.Do(req)
+	resp, err := getHTTPClient().Do(req)
 	if err != nil {
 		L.Push(lua.LNil)
 		L.Push(lua.LString(err.Error()))
diff --git a/pkg/obioptions/version.go b/pkg/obioptions/version.go
index 31199eb..86e46da 100644
--- a/pkg/obioptions/version.go
+++ b/pkg/obioptions/version.go
@@ -3,7 +3,7 @@ package obioptions
 // Version is automatically updated by the Makefile from version.txt
 // The patch number (third digit) is incremented on each push to the repository
 
-var _Version = "Release 4.4.33"
+var _Version = "Release 4.4.34"
 
 // Version returns the version of the obitools package.
 //
diff --git a/version.txt b/version.txt
index 1cfc545..b3f8f6f 100644
--- a/version.txt
+++ b/version.txt
@@ -1 +1 @@
-4.4.33
+4.4.34