diff --git a/README.markdown b/README.markdown
new file mode 100644
index 0000000..33be88d
--- /dev/null
+++ b/README.markdown
@@ -0,0 +1,6 @@
+Codegen
+=======
+
+- Each input schema corresponds to a single `.d.ts` file
+- 100% structurally map to TypeScript. Additional constraints might belong to
+  validation
diff --git a/src/ir/include/sourcemeta/codegen/ir.h b/src/ir/include/sourcemeta/codegen/ir.h
index 8e0c7f1..ea8f49d 100644
--- a/src/ir/include/sourcemeta/codegen/ir.h
+++ b/src/ir/include/sourcemeta/codegen/ir.h
@@ -6,11 +6,58 @@
 #endif
 
 #include <sourcemeta/core/json.h>
+#include <sourcemeta/core/jsonpointer.h>
 #include <sourcemeta/core/jsonschema.h>
 
+#include <cstdint>       // std::uint8_t
+#include <optional>      // std::optional, std::nullopt
+#include <unordered_map> // std::unordered_map
+#include <variant>       // std::variant
+#include <vector>        // std::vector
+
 /// @defgroup ir IR
 /// @brief The codegen JSON Schema intermediary format
 
-namespace sourcemeta::codegen {} // namespace sourcemeta::codegen
+namespace sourcemeta::codegen {
+
+/// @ingroup ir
+enum class IRScalarType : std::uint8_t { String };
+
+/// @ingroup ir
+struct IRObjectValue {
+  bool required;
+  bool immutable;
+  sourcemeta::core::PointerTemplate pointer;
+};
+
+/// @ingroup ir
+struct IRScalar {
+  sourcemeta::core::PointerTemplate pointer;
+  IRScalarType value;
+};
+
+/// @ingroup ir
+struct IRObject {
+  sourcemeta::core::PointerTemplate pointer;
+  std::unordered_map<sourcemeta::core::JSON::String, IRObjectValue> members;
+};
+
+/// @ingroup ir
+using IREntity = std::variant<IRObject, IRScalar>;
+
+/// @ingroup ir
+using IRResult = std::vector<IREntity>;
+
+/// @ingroup ir
+SOURCEMETA_CODEGEN_IR_EXPORT
+auto compile(const sourcemeta::core::JSON &schema,
+             const sourcemeta::core::SchemaWalker &walker,
+             const sourcemeta::core::SchemaResolver &resolver,
+             const std::optional<sourcemeta::core::JSON::String>
+                 &default_dialect = std::nullopt,
+             const std::optional<sourcemeta::core::JSON::String> &default_id =
+                 std::nullopt) -> IRResult;
+
+} // namespace sourcemeta::codegen
 
 #endif
diff --git a/src/ir/ir.cc b/src/ir/ir.cc
index 44108e9..defe2c1 100644
--- a/src/ir/ir.cc
+++ b/src/ir/ir.cc
@@ -1,3 +1,140 @@
 #include <sourcemeta/codegen/ir.h>
 
-namespace sourcemeta::codegen {} // namespace sourcemeta::codegen
+#include <algorithm>  // std::ranges::sort
+#include <functional> // std::reference_wrapper
+#include <map>        // std::map
+#include <vector>     // std::vector
+
+namespace sourcemeta::codegen {
+
+auto compile(
+    const sourcemeta::core::JSON &schema,
+    const sourcemeta::core::SchemaWalker &walker,
+    const sourcemeta::core::SchemaResolver &resolver,
+    const std::optional<sourcemeta::core::JSON::String> &default_dialect,
+    const std::optional<sourcemeta::core::JSON::String> &default_id)
+    -> IRResult {
+  sourcemeta::core::SchemaFrame frame{
+      sourcemeta::core::SchemaFrame::Mode::Instances};
+  frame.analyse(schema, walker, resolver, default_dialect, default_id);
+  std::map<sourcemeta::core::PointerTemplate,
+           std::vector<std::reference_wrapper<
+               const sourcemeta::core::SchemaFrame::Location>>>
+      instance_to_locations;
+  for (const auto &[key, location] : frame.locations()) {
+    if (location.type ==
+            sourcemeta::core::SchemaFrame::LocationType::Resource ||
+        location.type ==
+            sourcemeta::core::SchemaFrame::LocationType::Subschema) {
+      for (const auto &instance_location : frame.instance_locations(location)) {
+        instance_to_locations[instance_location].emplace_back(
+            std::cref(location));
+      }
+    }
+  }
+
+  IRResult result;
+
+  // Process each instance location group
+  for (const auto &[instance_location, locations] : instance_to_locations) {
+    for (const auto &location_ref : locations) {
+      const auto &location{location_ref.get()};
+      const auto &subschema{sourcemeta::core::get(schema, location.pointer)};
+      if (!subschema.is_object()) {
+        continue;
+      }
+
+      const auto vocabularies{frame.vocabularies(location, resolver)};
+
+      if (subschema.defines("type")) {
+        const auto &type_result{walker("type", vocabularies)};
+        if (type_result.type !=
+            sourcemeta::core::SchemaKeywordType::Assertion) {
+          continue;
+        }
+
+        const auto &type_value{subschema.at("type")};
+        if (!type_value.is_string()) {
+          continue;
+        }
+
+        const auto &type_string{type_value.to_string()};
+
+        if (type_string == "string") {
+          result.emplace_back(IRScalar{.pointer = instance_location,
+                                       .value = IRScalarType::String});
+        } else if (type_string == "object") {
+          IRObject object;
+          object.pointer = instance_location;
+
+          // Find child instance locations (one property token deeper)
+          for (const auto &[child_instance, child_locations] :
+               instance_to_locations) {
+            if (!child_instance.trivial() || child_instance.empty()) {
+              continue;
+            }
+
+            // Check if child is exactly one property token deeper
+            auto child_size{
+                std::distance(child_instance.begin(), child_instance.end())};
+            auto parent_size{std::distance(instance_location.begin(),
+                                           instance_location.end())};
+            if (child_size != parent_size + 1) {
+              continue;
+            }
+
+            // Verify parent prefix matches
+            auto matches{true};
+            auto child_iter{child_instance.begin()};
+            for (const auto &parent_token : instance_location) {
+              if (*child_iter != parent_token) {
+                matches = false;
+                break;
+              }
+              ++child_iter;
+            }
+
+            if (!matches) {
+              continue;
+            }
+
+            // Get the property name from the last token
+            const auto &last_token{*child_instance.rbegin()};
+            if (!std::holds_alternative<sourcemeta::core::Pointer::Token>(
+                    last_token)) {
+              continue;
+            }
+
+            const auto &property_token{
+                std::get<sourcemeta::core::Pointer::Token>(last_token)};
+            if (!property_token.is_property()) {
+              continue;
+            }
+
+            object.members.emplace(property_token.to_property(),
+                                   IRObjectValue{.required = false,
+                                                 .immutable = false,
+                                                 .pointer = child_instance});
+          }
+
+          result.emplace_back(std::move(object));
+        }
+      }
+    }
+  }
+
+  // Sort by pointer template (longer paths come first, so dependencies
+  // appear before their parents)
+  const auto get_pointer{
+      [](const auto &entry) -> const sourcemeta::core::PointerTemplate & {
+        return entry.pointer;
+      }};
+  std::ranges::sort(
+      result, [&get_pointer](const IREntity &a, const IREntity &b) -> bool {
+        return std::visit(get_pointer, b) < std::visit(get_pointer, a);
+      });
+
+  return result;
+}
+
+} // namespace sourcemeta::codegen
diff --git a/test/ir/ir_test.cc b/test/ir/ir_test.cc
index ede5198..ce2d7c0 100644
--- a/test/ir/ir_test.cc
+++ b/test/ir/ir_test.cc
@@ -2,4 +2,57 @@
 
 #include <sourcemeta/codegen/ir.h>
 
-TEST(IR, test_1) { EXPECT_TRUE(true); }
+TEST(IR, test_1) {
+  const sourcemeta::core::JSON schema{sourcemeta::core::parse_json(R"JSON({
+    "$schema": "https://json-schema.org/draft/2020-12/schema",
+    "type": "string"
+  })JSON")};
+
+  const auto result{
+      sourcemeta::codegen::compile(schema, sourcemeta::core::schema_walker,
+                                   sourcemeta::core::schema_resolver)};
+
+  using namespace sourcemeta::codegen;
+
+  EXPECT_EQ(result.size(), 1);
+
+  EXPECT_TRUE(std::holds_alternative<IRScalar>(result.at(0)));
+  EXPECT_TRUE(std::get<IRScalar>(result.at(0)).pointer.empty());
+  EXPECT_EQ(std::get<IRScalar>(result.at(0)).value, IRScalarType::String);
+}
+
+TEST(IR, test_2) {
+  const sourcemeta::core::JSON schema{sourcemeta::core::parse_json(R"JSON({
+    "$schema": "https://json-schema.org/draft/2020-12/schema",
+    "type": "object",
+    "properties": {
+      "foo": {
+        "type": "string"
+      }
+    }
+  })JSON")};
+
+  const auto result{
+      sourcemeta::codegen::compile(schema, sourcemeta::core::schema_walker,
+                                   sourcemeta::core::schema_resolver)};
+
+  using namespace sourcemeta::codegen;
+
+  EXPECT_EQ(result.size(), 2);
+
+  EXPECT_TRUE(std::holds_alternative<IRScalar>(result.at(0)));
+  EXPECT_EQ(
+      std::get<IRScalar>(result.at(0)).pointer,
+      sourcemeta::core::PointerTemplate{sourcemeta::core::Pointer{"foo"}});
+  EXPECT_EQ(std::get<IRScalar>(result.at(0)).value, IRScalarType::String);
+
+  EXPECT_TRUE(std::holds_alternative<IRObject>(result.at(1)));
+  EXPECT_TRUE(std::get<IRObject>(result.at(1)).pointer.empty());
+  EXPECT_EQ(std::get<IRObject>(result.at(1)).members.size(), 1);
+  EXPECT_TRUE(std::get<IRObject>(result.at(1)).members.contains("foo"));
+  EXPECT_FALSE(std::get<IRObject>(result.at(1)).members.at("foo").required);
+  EXPECT_FALSE(std::get<IRObject>(result.at(1)).members.at("foo").immutable);
+  EXPECT_EQ(
+      std::get<IRObject>(result.at(1)).members.at("foo").pointer,
+      sourcemeta::core::PointerTemplate{sourcemeta::core::Pointer{"foo"}});
+}