diff --git a/BENCHMARK.md b/BENCHMARK.md
index 24f1ccb..2b8d05e 100644
--- a/BENCHMARK.md
+++ b/BENCHMARK.md
@@ -1,25 +1,25 @@
-v1.12.2
+v1.13.0 stream mode: disabled
 
 ```planetext
- ✓ tests/test.benchmark.ts (10) 16034ms
-   ✓ warmup (1) 729ms
+ ✓ tests/test.benchmark.ts (10) 15606ms
+   ✓ warmup (1) 623ms
      name                  hz     min      max    mean     p75      p99     p995     p999     rme  samples
-   · warmup chiitiler  118.70  7.5679  11.9859  8.4244  8.6950  11.9859  11.9859  11.9859  ±2.49%       60
-   ✓ render (3) 5875ms
+   · warmup chiitiler  121.48  7.3079  11.4564  8.2318  8.4843  11.4564  11.4564  11.4564  ±2.95%       61
+   ✓ render (3) 5785ms
      name                hz     min     max    mean     p75     p99    p995    p999     rme  samples
-   · render as png   7.8713  119.50  134.62  127.04  129.59  134.62  134.62  134.62  ±2.59%       10
-   · render as webp  7.3926  125.52  152.92  135.27  137.71  152.92  152.92  152.92  ±5.29%       10   slowest
-   · render as jpeg  8.3924  112.76  122.70  119.16  121.61  122.70  122.70  122.70  ±1.69%       10   fastest
-   ✓ render with margin (3) 4541ms
-     name                             hz      min     max     mean     p75     p99    p995    p999      rme  samples
-   · render as png with margin   10.1103  88.4602  115.17  98.9094  108.64  115.17  115.17  115.17   ±7.21%       10   fastest
-   · render as webp with margin   9.3138  97.1585  117.95   107.37  113.95  117.95  117.95  117.95   ±4.84%       10   slowest
-   · render as jpeg with margin   9.8386  85.4708  146.32   101.64  106.88  146.32  146.32  146.32  ±12.84%       10
-   ✓ render tileSize=2048 (3) 4888ms
+   · render as png   7.6663  120.66  142.94  130.44  133.33  142.94  142.94  142.94  ±3.70%       10   slowest
+   · render as webp  7.8825  120.75  136.90  126.86  128.98  136.90  136.90  136.90  ±3.12%       10
+   · render as jpeg  8.3103  116.32  126.72  120.33  122.50  126.72  126.72  126.72  ±1.90%       10   fastest
+   ✓ render with margin (3) 4292ms
+     name                             hz      min     max     mean      p75     p99    p995    p999     rme  samples
+   · render as png with margin   10.1489  90.6246  121.02  98.5326   102.42  121.02  121.02  121.02  ±6.68%       10
+   · render as webp with margin   9.9230  91.8121  117.60   100.78   106.96  117.60  117.60  117.60  ±5.89%       10   slowest
+   · render as jpeg with margin  11.1188  82.7890  116.44  89.9379  89.0628  116.44  116.44  116.44  ±7.68%       10   fastest
+   ✓ render tileSize=2048 (3) 4904ms
      name                         hz      min      max     mean      p75      p99     p995     p999     rme  samples
-   · render as png: 2048px   13.0710  69.0875  83.4170  76.5054  78.3272  83.4170  83.4170  83.4170  ±3.65%       10
-   · render as webp: 2048px   5.1159   186.24   224.75   195.47   193.55   224.75   224.75   224.75  ±4.07%       10   slowest
-   · render as jpeg: 2048px  33.7627  26.7925  34.6572  29.6185  29.8150  34.6572  34.6572  34.6572  ±3.51%       17   fastest
+   · render as png: 2048px   12.3602  70.9358  96.1278  80.9046  88.8528  96.1278  96.1278  96.1278  ±7.47%       10
+   · render as webp: 2048px   5.0496   187.04   233.38   198.04   197.61   233.38   233.38   233.38  ±4.74%       10   slowest
+   · render as jpeg: 2048px  29.6039  28.5111  46.9135  33.7793  37.3103  46.9135  46.9135  46.9135  ±8.23%       15   fastest
 
 
  BENCH  Summary
@@ -27,14 +27,14 @@ v1.12.2
   warmup chiitiler - tests/test.benchmark.ts > warmup
 
   render as jpeg - tests/test.benchmark.ts > render
-    1.07x faster than render as png
-    1.14x faster than render as webp
+    1.05x faster than render as webp
+    1.08x faster than render as png
 
-  render as png with margin - tests/test.benchmark.ts > render with margin
-    1.03x faster than render as jpeg with margin
-    1.09x faster than render as webp with margin
+  render as jpeg with margin - tests/test.benchmark.ts > render with margin
+    1.10x faster than render as png with margin
+    1.12x faster than render as webp with margin
 
   render as jpeg: 2048px - tests/test.benchmark.ts > render tileSize=2048
-    2.58x faster than render as png: 2048px
-    6.60x faster than render as webp: 2048px
+    2.40x faster than render as png: 2048px
+    5.86x faster than render as webp: 2048px
 ```
diff --git a/README.md b/README.md
index bf8d70e..c54a6e4 100644
--- a/README.md
+++ b/README.md
@@ -95,6 +95,7 @@ you can pass server options via environment variables
 | CHIITILER_PORT                     | 3000     | port number                                    |
 | CHIITILER_PROCESSES                | 1        | num of chiitiler processes. 0 means all-CPUs   |
 | CHIITILER_DEBUG                    | false    | debug mode                                     |
+| CHIITILER_STREAM_MODE              | false    | stream mode                                    |
 | CHIITILER_CACHE_METHOD             | none     | cache method, `none`, `memory`, `file` or `s3` |
 | CHIITILER_CACHE_TTL_SEC            | 3600     | cache ttl, effect to `memory` and `file`       |
 | CHIITILER_MEMORYCACHE_MAXITEMCOUNT | 1000     | max items for memorycache                      |