diff --git a/deno/logging.ts b/deno/logging.ts
new file mode 100644
index 0000000..6e629f8
--- /dev/null
+++ b/deno/logging.ts
@@ -0,0 +1,44 @@
+// internal-logging.ts
+
+// FIXME: Move this to somewhere more appropriate
+type AtLeastOne<T> = [T, ...T[]];
+
+type MessageSource = "logging" | "diagnostic" | "user";
+
+type Message = {
+    // FIXME: number probably isn't what we want here
+    timestamp: number;
+    source: MessageSource;
+
+    text: AtLeastOne<string>;
+};
+
+const m1: Message = { timestamp: 123, source: "logging", text: ["foo"] };
+const m2: Message = {
+    timestamp: 321,
+    source: "diagnostic",
+    text: ["ok", "whatever"],
+};
+
+type FilterArgument = {
+    limit?: number;
+    before?: number;
+    after?: number;
+
+    // FIXME: add offsets to use instead of or in addition to before/after
+
+    match?: (string | RegExp)[];
+};
+
+const log = (_message: Message) => {
+    // WRITEME
+};
+
+const getLogs = (filter: FilterArgument) => {
+    // WRITEME
+};
+
+// FIXME: there's scope for more specialized functions although they
+// probably should be defined in terms of the basic ones here.
+
+export { getLogs, log };