diff --git a/rainfallwrangler/package-lock.json b/rainfallwrangler/package-lock.json
index 852b2d0..d937ded 100644
--- a/rainfallwrangler/package-lock.json
+++ b/rainfallwrangler/package-lock.json
@@ -13,6 +13,7 @@
         "applause-cli": "^1.8.1",
         "gunzip-maybe": "^1.4.2",
         "nexline": "^1.2.2",
+        "p-debounce": "^4.0.0",
         "p-map": "^5.5.0",
         "p-reflect": "^3.0.0",
         "pretty-ms": "^8.0.0",
@@ -1108,6 +1109,14 @@
         "wrappy": "1"
       }
     },
+    "node_modules/p-debounce": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/p-debounce/-/p-debounce-4.0.0.tgz",
+      "integrity": "sha512-4Ispi9I9qYGO4lueiLDhe4q4iK5ERK8reLsuzH6BPaXn53EGaua8H66PXIFGrW897hwjXp+pVLrm/DLxN0RF0A==",
+      "engines": {
+        "node": ">=12"
+      }
+    },
     "node_modules/p-map": {
       "version": "5.5.0",
       "resolved": "https://registry.npmjs.org/p-map/-/p-map-5.5.0.tgz",
@@ -2477,6 +2486,11 @@
         "wrappy": "1"
       }
     },
+    "p-debounce": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/p-debounce/-/p-debounce-4.0.0.tgz",
+      "integrity": "sha512-4Ispi9I9qYGO4lueiLDhe4q4iK5ERK8reLsuzH6BPaXn53EGaua8H66PXIFGrW897hwjXp+pVLrm/DLxN0RF0A=="
+    },
     "p-map": {
       "version": "5.5.0",
       "resolved": "https://registry.npmjs.org/p-map/-/p-map-5.5.0.tgz",
diff --git a/rainfallwrangler/package.json b/rainfallwrangler/package.json
index 0a5964a..dc68942 100644
--- a/rainfallwrangler/package.json
+++ b/rainfallwrangler/package.json
@@ -17,6 +17,7 @@
     "applause-cli": "^1.8.1",
     "gunzip-maybe": "^1.4.2",
     "nexline": "^1.2.2",
+    "p-debounce": "^4.0.0",
     "p-map": "^5.5.0",
     "p-reflect": "^3.0.0",
     "pretty-ms": "^8.0.0",
diff --git a/rainfallwrangler/src/lib/async/debounce.mjs b/rainfallwrangler/src/lib/async/debounce.mjs
new file mode 100644
index 0000000..a21f08c
--- /dev/null
+++ b/rainfallwrangler/src/lib/async/debounce.mjs
@@ -0,0 +1,20 @@
+"use strict";
+
+/**
+ * Returns a function that debounces the given function.
+ * The function will only be called every INTERVAL number of milliseconds - additional
+ * calls return immediately without calling the provided function.
+ * Useful e.g. debouncing the scroll event in a browser.
+ * Note that p-debounce throttles the function, whereas this debounce implementation CANCELS additional calls to it.
+ * @param	{function}	fn			The function to debounce.
+ * @param	{number}	interval	The interval - in milliseconds - that the function should be called at.
+ * @return	{function}	A debounced wrapper function around the specified function.
+ */
+export default function(fn, interval) {
+	const time_last = 0;
+	return (...args) => {
+		const now = new Date();
+		if(now - time_last > interval)
+			fn(...args);
+	}
+}
\ No newline at end of file
diff --git a/rainfallwrangler/src/lib/python/py_jsonl2tfrecord.mjs b/rainfallwrangler/src/lib/python/py_jsonl2tfrecord.mjs
new file mode 100644
index 0000000..ed310db
--- /dev/null
+++ b/rainfallwrangler/src/lib/python/py_jsonl2tfrecord.mjs
@@ -0,0 +1,47 @@
+"use strict";
+
+import fs from 'fs';
+import child_process from 'child_process';
+
+import nexline from nexline;
+
+import log from './NamespacedLog.mjs'; const l = log("gzipchildprocess");
+import { end_safe } from './StreamHelpers.mjs';
+import { fstat } from 'fs';
+
+
+const __dirname = import.meta.url.slice(7, import.meta.url.lastIndexOf("/"));
+
+async function* py_jsonl2tfrecord(filepath_source, filepath_target, filepath_meta=null) {
+	// get stdin() { return this.child_process.stdin; }
+	// get stdout() { return this.child_process.stdout; }
+	// get stderr() { return this.child_process.stderr; }
+	
+	
+	child_process = child_process.spawn(
+		"python3", [
+			path.join(__dirname, "json2tfrecord.py"),
+			"--input", filepath_source,
+			"--output", filepath_target
+		], { // TODO: detect binary - python3 vs python
+			// Pipe stdin + stdout; send error to the parent process
+			stdio: [ "ignore", "pipe", "inherit" ]
+		}
+	);
+	
+	const reader = nexline({ input: child_process.stdout });
+	
+	for await(const line of reader) {
+		if(line.startsWith("SHAPE") && filepath_meta !== null ) {
+			await fs.promises.writeFile(
+				filepath_meta,
+				line.split(/\t+/)[1]
+			);
+			continue;
+		}
+		
+		yield parseInt(line, 10);
+	}
+}
+
+export default py_jsonl2tfrecord;
diff --git a/rainfallwrangler/src/lib/record/jsonl_to_tf.mjs b/rainfallwrangler/src/lib/record/jsonl_to_tf.mjs
new file mode 100644
index 0000000..2228e3f
--- /dev/null
+++ b/rainfallwrangler/src/lib/record/jsonl_to_tf.mjs
@@ -0,0 +1,34 @@
+"use strict";
+
+import fs from 'fs';
+import path from 'path';
+import p_map from 'p-map';
+import pretty_ms from 'pretty-ms';
+
+import debounce from '../async/debounce.mjs';
+import py_jsonl2tfrecord from '../python/py_jsonl2tfrecord.mjs';
+import log from '../../lib/io/NamespacedLog.mjs'; const l = log("jsonl2tf");
+
+export default async function(dirpath_source, dirpath_target) {
+	const files = fs.promises.readdir(dirpath_source);
+	
+	let time_start = new Date(), lines_processed = 0, files_complete = 0;
+	
+	const update_progress = debounce(() => {
+		process.stdout.write(`${files_complete}/${lines_processed} files/lines complete | ${((new Date() - time_start) / lines_processed).toFixed(3)} lines/sec | ${((files_processed / files.length)*100).toFixed(2)}% complete\r`);
+	});
+	
+	p_map(files, async (filename, i) => {
+		const filepath_source = path.join(dirpath_source, filename);
+		const filepath_dest = path.join(dirpath_target, filename);
+		const filepath_meta = i === 0 ? path.join(dirpath_target, `metadata.json`) : null;
+		let time_start = new Date(), lines_done = 0;
+		for await (let line_number of py_jsonl2tfrecord(filepath_source, filepath_dest, filepath_meta)) {
+			lines_processed++;
+			lines_done = line_number;
+			update_progress();
+		}
+		files_complete++;
+		l.log(`converted ${filename}: ${lines_done} lines @ ${pretty_ms((new Date() - time_start) / lines_done)}`);
+	});
+}