diff --git a/.builds/c-enabled.yml b/.builds/c-enabled.yml
index b314a022cbdf4e6f1294f3fd698f197ff0e348c2..6f03b0564c3a1103959b6566f59e667367981034 100644
--- a/.builds/c-enabled.yml
+++ b/.builds/c-enabled.yml
@@ -6,6 +6,10 @@   - gnupg
   - protobuf-compiler
   - cmake
   - build-essential
+  - unzip
+secrets:
+  - 7dde4219-0783-4581-a67d-c94749de3600   # ~/.s3-cache-key-id
+  - 0e5b3530-6f19-4f30-9b73-9339dd382e46   # ~/.s3-cache-key-secret
 sources:
   - https://git.srht.bigb.es/~bigbes/tarantool-protobuf
 environment:
@@ -14,6 +18,9 @@   GOROOT: /home/build/.local/go
   GO_VERSION: "1.26.3"
   PATH: /home/build/.local/go/bin:/home/build/.local/bin:/home/build/go/bin:/usr/local/bin:/usr/bin:/bin
   PB_ENABLE_C: "1"
+  AWS_DEFAULT_REGION: garage
+  AWS_ENDPOINT_URL: https://s3.bigb.es
+  S3_BUCKET: docker-cache
 submitter:
   git.sr.ht:
     enabled: true
@@ -21,10 +28,50 @@     allow-refs:
       - refs/heads/master
       - "refs/tags/*"
 tasks:
+  - install_awscli: |
+      curl -sSL "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" \
+        -o /tmp/awscliv2.zip
+      unzip -q /tmp/awscliv2.zip -d /tmp
+      sudo /tmp/aws/install
+      aws --version
+  - aws_credentials: |
+      mkdir -p ~/.aws
+      cat > ~/.aws/config <<EOF
+      [default]
+      region = $AWS_DEFAULT_REGION
+      s3 =
+          addressing_style = path
+          signature_version = s3v4
+      EOF
+      echo 'export AWS_REQUEST_CHECKSUM_CALCULATION=when_required'  >> ~/.buildenv
+      echo 'export AWS_RESPONSE_CHECKSUM_VALIDATION=when_required' >> ~/.buildenv
+      set +x
+      export AWS_ACCESS_KEY_ID=$(tr -d '[:space:]' < ~/.s3-cache-key-id)
+      export AWS_SECRET_ACCESS_KEY=$(tr -d '[:space:]' < ~/.s3-cache-key-secret)
+      {
+        printf 'export AWS_ACCESS_KEY_ID=%q\n'     "$AWS_ACCESS_KEY_ID"
+        printf 'export AWS_SECRET_ACCESS_KEY=%q\n' "$AWS_SECRET_ACCESS_KEY"
+      } >> ~/.buildenv
+      set -x
+      aws --endpoint-url="$AWS_ENDPOINT_URL" s3 ls "s3://$S3_BUCKET/" >/dev/null
   - install_go: |
+      GO_TARBALL="go${GO_VERSION}.linux-amd64.tar.gz"
+      GO_KEY="golang/$GO_TARBALL"
+      GO_URI="s3://$S3_BUCKET/$GO_KEY"
       mkdir -p ~/.local
-      curl -sSL "https://go.dev/dl/go${GO_VERSION}.linux-amd64.tar.gz" \
-        | tar -xz -C ~/.local
+      if aws --endpoint-url="$AWS_ENDPOINT_URL" s3api head-object \
+           --bucket "$S3_BUCKET" --key "$GO_KEY" >/dev/null 2>&1; then
+        echo "Cache HIT — pulling Go from S3"
+        aws --endpoint-url="$AWS_ENDPOINT_URL" s3 cp "$GO_URI" - \
+          | tar -xz -C ~/.local
+      else
+        echo "Cache MISS — downloading from go.dev and caching"
+        curl -sSL --retry 3 --retry-delay 5 --max-time 300 \
+          "https://go.dev/dl/$GO_TARBALL" -o "/tmp/$GO_TARBALL"
+        tar -xz -C ~/.local -f "/tmp/$GO_TARBALL"
+        aws --endpoint-url="$AWS_ENDPOINT_URL" s3 cp "/tmp/$GO_TARBALL" "$GO_URI"
+        rm "/tmp/$GO_TARBALL"
+      fi
       go version
   - install_tarantool: |
       curl -L https://tarantool.io/release/3/installer.sh | sudo bash
diff --git a/.builds/conformance.yml b/.builds/conformance.yml
index d53942bccf3918aac24631363338edc4d8417587..983c60d42909bce1b92fae2bd9b5ca24f55eed87 100644
--- a/.builds/conformance.yml
+++ b/.builds/conformance.yml
@@ -69,9 +69,23 @@       echo "secret_len=${#AWS_SECRET_ACCESS_KEY}"
       set -x
       aws --endpoint-url="$AWS_ENDPOINT_URL" s3 ls "s3://$S3_BUCKET/" >/dev/null
   - install_go: |
+      GO_TARBALL="go${GO_VERSION}.linux-amd64.tar.gz"
+      GO_KEY="golang/$GO_TARBALL"
+      GO_URI="s3://$S3_BUCKET/$GO_KEY"
       mkdir -p ~/.local
-      curl -sSL "https://go.dev/dl/go${GO_VERSION}.linux-amd64.tar.gz" \
-        | tar -xz -C ~/.local
+      if aws --endpoint-url="$AWS_ENDPOINT_URL" s3api head-object \
+           --bucket "$S3_BUCKET" --key "$GO_KEY" >/dev/null 2>&1; then
+        echo "Cache HIT — pulling Go from S3"
+        aws --endpoint-url="$AWS_ENDPOINT_URL" s3 cp "$GO_URI" - \
+          | tar -xz -C ~/.local
+      else
+        echo "Cache MISS — downloading from go.dev and caching"
+        curl -sSL --retry 3 --retry-delay 5 --max-time 300 \
+          "https://go.dev/dl/$GO_TARBALL" -o "/tmp/$GO_TARBALL"
+        tar -xz -C ~/.local -f "/tmp/$GO_TARBALL"
+        aws --endpoint-url="$AWS_ENDPOINT_URL" s3 cp "/tmp/$GO_TARBALL" "$GO_URI"
+        rm "/tmp/$GO_TARBALL"
+      fi
       go version
   - install_tarantool: |
       curl -L https://tarantool.io/release/3/installer.sh | sudo bash
diff --git a/.builds/pure-lua.yml b/.builds/pure-lua.yml
index e3746f4f81cea3709b1113a63ab1f2f1776aec63..1413d9146091cc3a3c4b5455f356fe9bf742f1fd 100644
--- a/.builds/pure-lua.yml
+++ b/.builds/pure-lua.yml
@@ -6,6 +6,10 @@   - gnupg
   - protobuf-compiler
   - cmake
   - build-essential
+  - unzip
+secrets:
+  - 7dde4219-0783-4581-a67d-c94749de3600   # ~/.s3-cache-key-id
+  - 0e5b3530-6f19-4f30-9b73-9339dd382e46   # ~/.s3-cache-key-secret
 sources:
   - https://git.srht.bigb.es/~bigbes/tarantool-protobuf
 environment:
@@ -13,6 +17,9 @@   GOPATH: /home/build/go
   GOROOT: /home/build/.local/go
   GO_VERSION: "1.26.3"
   PATH: /home/build/.local/go/bin:/home/build/.local/bin:/home/build/go/bin:/usr/local/bin:/usr/bin:/bin
+  AWS_DEFAULT_REGION: garage
+  AWS_ENDPOINT_URL: https://s3.bigb.es
+  S3_BUCKET: docker-cache
 submitter:
   git.sr.ht:
     enabled: true
@@ -20,10 +27,50 @@     allow-refs:
       - refs/heads/master
       - "refs/tags/*"
 tasks:
+  - install_awscli: |
+      curl -sSL "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" \
+        -o /tmp/awscliv2.zip
+      unzip -q /tmp/awscliv2.zip -d /tmp
+      sudo /tmp/aws/install
+      aws --version
+  - aws_credentials: |
+      mkdir -p ~/.aws
+      cat > ~/.aws/config <<EOF
+      [default]
+      region = $AWS_DEFAULT_REGION
+      s3 =
+          addressing_style = path
+          signature_version = s3v4
+      EOF
+      echo 'export AWS_REQUEST_CHECKSUM_CALCULATION=when_required'  >> ~/.buildenv
+      echo 'export AWS_RESPONSE_CHECKSUM_VALIDATION=when_required' >> ~/.buildenv
+      set +x
+      export AWS_ACCESS_KEY_ID=$(tr -d '[:space:]' < ~/.s3-cache-key-id)
+      export AWS_SECRET_ACCESS_KEY=$(tr -d '[:space:]' < ~/.s3-cache-key-secret)
+      {
+        printf 'export AWS_ACCESS_KEY_ID=%q\n'     "$AWS_ACCESS_KEY_ID"
+        printf 'export AWS_SECRET_ACCESS_KEY=%q\n' "$AWS_SECRET_ACCESS_KEY"
+      } >> ~/.buildenv
+      set -x
+      aws --endpoint-url="$AWS_ENDPOINT_URL" s3 ls "s3://$S3_BUCKET/" >/dev/null
   - install_go: |
+      GO_TARBALL="go${GO_VERSION}.linux-amd64.tar.gz"
+      GO_KEY="golang/$GO_TARBALL"
+      GO_URI="s3://$S3_BUCKET/$GO_KEY"
       mkdir -p ~/.local
-      curl -sSL "https://go.dev/dl/go${GO_VERSION}.linux-amd64.tar.gz" \
-        | tar -xz -C ~/.local
+      if aws --endpoint-url="$AWS_ENDPOINT_URL" s3api head-object \
+           --bucket "$S3_BUCKET" --key "$GO_KEY" >/dev/null 2>&1; then
+        echo "Cache HIT — pulling Go from S3"
+        aws --endpoint-url="$AWS_ENDPOINT_URL" s3 cp "$GO_URI" - \
+          | tar -xz -C ~/.local
+      else
+        echo "Cache MISS — downloading from go.dev and caching"
+        curl -sSL --retry 3 --retry-delay 5 --max-time 300 \
+          "https://go.dev/dl/$GO_TARBALL" -o "/tmp/$GO_TARBALL"
+        tar -xz -C ~/.local -f "/tmp/$GO_TARBALL"
+        aws --endpoint-url="$AWS_ENDPOINT_URL" s3 cp "/tmp/$GO_TARBALL" "$GO_URI"
+        rm "/tmp/$GO_TARBALL"
+      fi
       go version
   - install_tarantool: |
       curl -L https://tarantool.io/release/3/installer.sh | sudo bash