diff --git a/README.md b/README.md
index 8b38556..9d45729 100644
--- a/README.md
+++ b/README.md
@@ -1,40 +1,27 @@
 Cache Action
 ============
 
-A Gitea Action that caches build files under `~/.cache/` using a key file hash. This action uses `actions/cache@v5` under the hood and automatically saves the cache when the job completes successfully.
+A Gitea Action that caches build files under `~/.cache/` using a key file hash. Implements the Gitea artifact cache API directly with curl, tar, and zstd — no external actions required.
 
 ## Inputs
 
 | Input | Description | Required | Default |
 |-------|-------------|----------|---------|
 | `path` | Files/directories to cache | No | `~/.cache/` |
-| `key` | Explicit cache key | No | Auto-generated from hash |
-| `key-file` | File to hash for cache key generation | No | Auto-detects lockfiles |
-| `restore-keys` | Fallback prefix-matched keys | No | `{os}-cache-` |
+| `key-prefix` | Prefix for the cache key | Yes | — |
+| `key-file` | File to hash for the cache key | Yes | — |
+| `restore-keys` | Fallback prefix-matched keys | No | — |
 
 ## Outputs
 
 | Output | Description |
 |--------|-------------|
 | `cache-hit` | `true` if exact key match found, `false` otherwise |
+| `cache-primary-key` | The primary key used for cache lookup |
+| `cache-matched-key` | The key of the cache entry that was restored |
 
 ## Quick Start
 
-### Basic Usage
-
-```yaml
-name: Build with Cache
-on: push
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: Actions/Cache@main
-      - run: echo "Cache restored, proceeding with build..."
-```
-
 ### Rust Example
 
 ```yaml
@@ -52,6 +39,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: Actions/Cache@main
         with:
+          key-prefix: 'rust'
           key-file: 'Cargo.lock'
           path: |
             ~/.cache/
@@ -77,6 +65,7 @@ jobs:
       - uses: Actions/Cache@main
         id: cache
         with:
+          key-prefix: 'rust'
           key-file: 'Cargo.lock'
       - name: Install dependencies
         if: steps.cache.outputs.cache-hit != 'true'
@@ -87,14 +76,11 @@ jobs:
 
 ## How It Works
 
-1. **Cache Key Generation**: If no explicit `key` is provided, the action auto-generates one by:
-   - Hashing the specified `key-file` if provided
-   - Otherwise, hashing all detected lockfiles (package-lock.json, Cargo.lock, go.mod, etc.)
-   - Falls back to hashing all non-git files if no lockfiles found
+1. **Cache Key Generation**: Combines `key-prefix` with the SHA-256 hash of `key-file` (e.g. `rust-<hash>`).
 
-2. **Cache Restore**: Uses `actions/cache@v5` to restore the cache from `~/.cache/`
+2. **Cache Restore**: Calls the Gitea artifact cache API (`/_apis/artifactcache/cache`) to find a matching entry, downloads the archive, and extracts it.
 
-3. **Cache Save**: Automatically saves the cache when the job completes successfully (handled by `actions/cache@v5`)
+3. **Cache Save**: Runs on job completion (`if: always()`), creates a zstd-compressed tar archive, reserves a cache entry via the API, uploads it, and commits it. Skipped if there was a cache hit on the primary key.
 
 ## Cache Scope
 
@@ -102,6 +88,6 @@ The cache is scoped to the key, version, and branch. The default branch cache is
 
 ## Remarks
 
-- Requires Gitea Actions runner version >= 2.327.1 for `actions/cache@v5`
 - The cache server must be enabled on your Gitea instance
+- Requires `curl`, `tar`, and `sha256sum` on the runner (zstd is optional, falls back to gzip)
 - Maximum cache size per repository is 10GB
diff --git a/action.yaml b/action.yaml
index 0416098..b003e6c 100644
--- a/action.yaml
+++ b/action.yaml
@@ -5,13 +5,12 @@ inputs:
     description: 'A list of files, directories, or wildcard patterns to cache. Defaults to ~/.cache/'
     required: false
     default: '~/.cache/'
-  key:
-    description: 'An explicit key for a cache entry. Defaults to runner.os-cache-{hash}'
-    required: false
+  key-prefix:
+    description: 'Prefix for the cache key, combined with key-file hash'
+    required: true
   key-file:
-    description: 'The file to hash for generating the cache key. Used if key is not provided.'
-    required: false
-    default: ''
+    description: 'The file to hash for generating the cache key'
+    required: true
   restore-keys:
     description: 'An ordered list of prefix-matched keys for restoring stale cache'
     required: false
@@ -20,29 +19,227 @@ outputs:
   cache-hit:
     description: 'A boolean value to indicate an exact match was found for the key'
     value: ${{ steps.restore-cache.outputs.cache-hit }}
+  cache-primary-key:
+    description: 'The primary key used for cache lookup'
+    value: ${{ steps.restore-cache.outputs.cache-primary-key }}
+  cache-matched-key:
+    description: 'The key of the cache entry that was restored'
+    value: ${{ steps.restore-cache.outputs.cache-matched-key }}
 runs:
   using: "composite"
   steps:
     - name: Generate cache key
       id: gen-key
-      if: inputs.key == ''
       shell: bash
       run: |
-        if [ -n "${{ inputs.key-file }}" ]; then
-          KEY_HASH=$(sha256sum "${{ inputs.key-file }}" | awk '{print $1}')
-        else
-          KEY_HASH=$(find . -type f \( -name "*.csproj" -o -name "*.sln" -o -name "package.json" -o -name "package-lock.json" -o -name "yarn.lock" -o -name "pnpm-lock.yaml" -o -name "Cargo.lock" -o -name "requirements.txt" -o -name "Pipfile.lock" -o -name "go.mod" -o -name "go.sum" -o -name "pom.xml" -o -name "build.gradle*" -o -name "Gemfile.lock" -o -name "composer.lock" \) -exec sha256sum {} + 2>/dev/null | sha256sum | awk '{print $1}')
-          if [ "$KEY_HASH" = "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855" ]; then
-            KEY_HASH=$(find . -type f -not -path './.git/*' -not -path './.cache/*' | sort | xargs sha256sum 2>/dev/null | sha256sum | awk '{print $1}')
-          fi
-        fi
-        echo "cache-key=${{ runner.os }}-cache-${KEY_HASH}" >> $GITHUB_OUTPUT
+        KEY_HASH=$(sha256sum "${{ inputs.key-file }}" | awk '{print $1}')
+        echo "cache-key=${{ inputs.key-prefix }}-${KEY_HASH}" >> $GITHUB_OUTPUT
 
     - name: Restore cache
       id: restore-cache
-      uses: actions/cache@v5
-      with:
-        path: ${{ inputs.path }}
-        key: ${{ inputs.key != '' && inputs.key || steps.gen-key.outputs.cache-key }}
-        restore-keys: ${{ inputs.restore-keys != '' && inputs.restore-keys || format('{0}-cache-', runner.os) }}
+      shell: bash
+      env:
+        CACHE_KEY: ${{ steps.gen-key.outputs.cache-key }}
+        RESTORE_KEYS: ${{ inputs.restore-keys }}
+        CACHE_PATH: ${{ inputs.path }}
+      run: |
+        CACHE_URL="${ACTIONS_CACHE_URL:-${ACTIONS_RUNTIME_URL:-}}"
+        TOKEN="${ACTIONS_RUNTIME_TOKEN:-}"
 
+        if [ -z "$CACHE_URL" ] || [ -z "$TOKEN" ]; then
+          echo "::warning::Cache environment variables not set. Skipping cache restore."
+          echo "cache-hit=false" >> $GITHUB_OUTPUT
+          echo "cache-primary-key=${CACHE_KEY}" >> $GITHUB_OUTPUT
+          echo "cache-matched-key=" >> $GITHUB_OUTPUT
+          exit 0
+        fi
+
+        CACHE_URL="${CACHE_URL%/}/"
+        API_BASE="${CACHE_URL}_apis/artifactcache/"
+
+        EXPANDED_PATH=$(eval echo "$CACHE_PATH")
+        PATHS_HASH=$(echo "$EXPANDED_PATH" | sha256sum | awk '{print $1}')
+        CACHE_VERSION="zstd-${PATHS_HASH}"
+
+        PRIMARY_KEY="${CACHE_KEY}"
+
+        KEYS="$PRIMARY_KEY"
+        if [ -n "$RESTORE_KEYS" ]; then
+          while IFS= read -r rk; do
+            if [ -n "$rk" ]; then
+              KEYS="${KEYS},${rk}"
+            fi
+          done <<< "$RESTORE_KEYS"
+        fi
+
+        ENCODED_KEYS=$(echo "$KEYS" | sed 's/,/%2C/g')
+
+        echo "Looking up cache with keys: ${KEYS}"
+
+        HTTP_CODE=$(mktemp)
+        CACHE_ENTRY=$(mktemp)
+        curl -sL -w "%{http_code}" -o "$CACHE_ENTRY" \
+          -H "Authorization: Bearer ${TOKEN}" \
+          "${API_BASE}cache?keys=${ENCODED_KEYS}&version=${CACHE_VERSION}" \
+          2>/dev/null > "$HTTP_CODE" || true
+
+        STATUS=$(cat "$HTTP_CODE")
+        rm -f "$HTTP_CODE"
+
+        if [ "$STATUS" = "204" ] || [ "$STATUS" = "404" ] || [ ! -s "$CACHE_ENTRY" ]; then
+          echo "Cache not found for keys: ${KEYS}"
+          rm -f "$CACHE_ENTRY"
+          echo "cache-hit=false" >> $GITHUB_OUTPUT
+          echo "cache-primary-key=${PRIMARY_KEY}" >> $GITHUB_OUTPUT
+          echo "cache-matched-key=" >> $GITHUB_OUTPUT
+          exit 0
+        fi
+
+        ARCHIVE_LOCATION=$(grep -o '"archiveLocation":"[^"]*"' "$CACHE_ENTRY" | head -1 | cut -d'"' -f4)
+        MATCHED_KEY=$(grep -o '"cacheKey":"[^"]*"' "$CACHE_ENTRY" | head -1 | cut -d'"' -f4)
+        rm -f "$CACHE_ENTRY"
+
+        if [ -z "$ARCHIVE_LOCATION" ]; then
+          echo "Cache not found (no archive location)"
+          echo "cache-hit=false" >> $GITHUB_OUTPUT
+          echo "cache-primary-key=${PRIMARY_KEY}" >> $GITHUB_OUTPUT
+          echo "cache-matched-key=" >> $GITHUB_OUTPUT
+          exit 0
+        fi
+
+        echo "Cache found with key: ${MATCHED_KEY}"
+
+        EXACT_HIT="false"
+        if [ "$PRIMARY_KEY" = "$MATCHED_KEY" ]; then
+          EXACT_HIT="true"
+        fi
+
+        TMPDIR=$(mktemp -d)
+        ARCHIVE_PATH="${TMPDIR}/cache.tar.zst"
+
+        echo "Downloading cache archive..."
+        curl -sL -o "$ARCHIVE_PATH" "$ARCHIVE_LOCATION"
+
+        echo "Extracting cache..."
+        mkdir -p "$EXPANDED_PATH"
+
+        if command -v zstd &>/dev/null; then
+          tar -I zstd -xf "$ARCHIVE_PATH" -C "/" 2>/dev/null || true
+        else
+          tar -xf "$ARCHIVE_PATH" -C "/" 2>/dev/null || true
+        fi
+
+        rm -rf "$TMPDIR"
+
+        echo "cache-hit=${EXACT_HIT}" >> $GITHUB_OUTPUT
+        echo "cache-primary-key=${PRIMARY_KEY}" >> $GITHUB_OUTPUT
+        echo "cache-matched-key=${MATCHED_KEY}" >> $GITHUB_OUTPUT
+
+    - name: Save cache
+      if: always()
+      shell: bash
+      env:
+        CACHE_KEY: ${{ steps.gen-key.outputs.cache-key }}
+        CACHE_PATH: ${{ inputs.path }}
+        CACHE_HIT: ${{ steps.restore-cache.outputs.cache-hit }}
+      run: |
+        CACHE_URL="${ACTIONS_CACHE_URL:-${ACTIONS_RUNTIME_URL:-}}"
+        TOKEN="${ACTIONS_RUNTIME_TOKEN:-}"
+
+        if [ -z "$CACHE_URL" ] || [ -z "$TOKEN" ]; then
+          echo "::warning::Cache environment variables not set. Skipping cache save."
+          exit 0
+        fi
+
+        CACHE_URL="${CACHE_URL%/}/"
+        API_BASE="${CACHE_URL}_apis/artifactcache/"
+
+        EXPANDED_PATH=$(eval echo "$CACHE_PATH")
+        PATHS_HASH=$(echo "$EXPANDED_PATH" | sha256sum | awk '{print $1}')
+        CACHE_VERSION="zstd-${PATHS_HASH}"
+
+        PRIMARY_KEY="${CACHE_KEY}"
+
+        if [ "$CACHE_HIT" = "true" ]; then
+          echo "Cache hit on primary key, skipping save."
+          exit 0
+        fi
+
+        echo "Checking if cache directory has content..."
+        if [ ! -d "$EXPANDED_PATH" ] || [ -z "$(ls -A "$EXPANDED_PATH" 2>/dev/null)" ]; then
+          echo "Cache directory is empty, skipping save."
+          exit 0
+        fi
+
+        TMPDIR=$(mktemp -d)
+        REL_PATH="$(echo "$EXPANDED_PATH" | sed 's|^/||')"
+
+        ARCHIVE_PATH="${TMPDIR}/cache.tar.zst"
+        COMPRESS_METHOD="zstd"
+
+        if command -v zstd &>/dev/null; then
+          tar -I zstd -cf "$ARCHIVE_PATH" -C "/" "$REL_PATH" 2>/dev/null || COMPRESS_METHOD="none"
+        else
+          COMPRESS_METHOD="none"
+        fi
+
+        if [ "$COMPRESS_METHOD" = "none" ]; then
+          echo "zstd not available, trying gzip..."
+          ARCHIVE_PATH="${TMPDIR}/cache.tar.gz"
+          tar -czf "$ARCHIVE_PATH" -C "/" "$REL_PATH" 2>/dev/null || {
+            echo "Failed to create archive"
+            rm -rf "$TMPDIR"
+            exit 0
+          }
+        fi
+
+        ARCHIVE_SIZE=$(stat -c%s "$ARCHIVE_PATH" 2>/dev/null || stat -f%z "$ARCHIVE_PATH" 2>/dev/null || echo "0")
+
+        echo "Reserving cache with key: ${PRIMARY_KEY} (size: ${ARCHIVE_SIZE} bytes)"
+
+        RESERVE_RESPONSE=$(mktemp)
+        curl -sL -o "$RESERVE_RESPONSE" -w "%{http_code}" \
+          -X POST \
+          -H "Authorization: Bearer ${TOKEN}" \
+          -H "Content-Type: application/json" \
+          -d "{\"key\":\"${PRIMARY_KEY}\",\"version\":\"${CACHE_VERSION}\",\"cacheSize\":${ARCHIVE_SIZE}}" \
+          "${API_BASE}caches" 2>/dev/null > /dev/null || echo "000"
+
+        CACHE_ID=$(grep -o '"cacheId":[0-9]*' "$RESERVE_RESPONSE" | head -1 | cut -d':' -f2)
+        rm -f "$RESERVE_RESPONSE"
+
+        if [ -z "$CACHE_ID" ]; then
+          echo "No cache ID returned, cache may already exist or reservation failed"
+          rm -rf "$TMPDIR"
+          exit 0
+        fi
+
+        echo "Uploading cache (ID: ${CACHE_ID})..."
+        UPLOAD_STATUS=$(curl -sL -o /dev/null -w "%{http_code}" \
+          -X PATCH \
+          -H "Authorization: Bearer ${TOKEN}" \
+          -H "Content-Type: application/octet-stream" \
+          --data-binary "@${ARCHIVE_PATH}" \
+          "${API_BASE}caches/${CACHE_ID}" 2>/dev/null || echo "000")
+
+        if [ "$UPLOAD_STATUS" != "200" ]; then
+          echo "Upload failed with status: ${UPLOAD_STATUS}"
+          rm -rf "$TMPDIR"
+          exit 0
+        fi
+
+        echo "Committing cache..."
+        COMMIT_STATUS=$(curl -sL -o /dev/null -w "%{http_code}" \
+          -X POST \
+          -H "Authorization: Bearer ${TOKEN}" \
+          -H "Content-Type: application/json" \
+          -d "{\"size\":${ARCHIVE_SIZE}}" \
+          "${API_BASE}caches/${CACHE_ID}" 2>/dev/null || echo "000")
+
+        rm -rf "$TMPDIR"
+
+        if [ "$COMMIT_STATUS" = "200" ]; then
+          echo "Cache saved successfully"
+        else
+          echo "Commit failed with status: ${COMMIT_STATUS}"
+        fi