diff --git a/pyproject.toml b/pyproject.toml
index b910b62..d89d360 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -5,11 +5,14 @@ description = "High-throughput telecom CDR ingestion and analytics pipeline"
 requires-python = ">=3.11"
 dependencies = [
     "phonenumbers>=8.13",
+    "fastapi>=0.115,<1.0",
+    "uvicorn[standard]>=0.30,<1.0",
 ]
 
 [project.optional-dependencies]
 dev = [
     "pytest>=8.0",
+    "httpx>=0.27,<1.0",
 ]
 
 [build-system]
diff --git a/src/core/api/__init__.py b/src/core/api/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/core/api/main.py b/src/core/api/main.py
new file mode 100644
index 0000000..4884f65
--- /dev/null
+++ b/src/core/api/main.py
@@ -0,0 +1,22 @@
+from fastapi import FastAPI
+
+from core.api.routes import router
+
+
+app = FastAPI(
+    title="Telecom CDR Ingestion API",
+    version="0.1.0",
+)
+
+
+app.include_router(
+    router,
+    prefix="/api/v1",
+)
+
+
+@app.get("/health")
+async def health() -> dict[str, str]:
+    return {
+        "status": "ok",
+    }
\ No newline at end of file
diff --git a/src/core/api/routes.py b/src/core/api/routes.py
new file mode 100644
index 0000000..6ec68ee
--- /dev/null
+++ b/src/core/api/routes.py
@@ -0,0 +1,58 @@
+import json
+
+from fastapi import APIRouter, Request, status
+from fastapi.responses import JSONResponse
+
+from core.domain.errors import CDRProcessingError
+from core.domain.validation import parse_raw_cdr
+
+
+router = APIRouter()
+
+
+@router.post(
+    "/cdr/raw",
+    status_code=status.HTTP_202_ACCEPTED,
+)
+async def ingest_raw_cdr(request: Request) -> JSONResponse:
+    try:
+        payload = await request.json()
+
+    except (json.JSONDecodeError, UnicodeDecodeError) as exc:
+        return JSONResponse(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            content={
+                "error": "invalid_json",
+                "detail": str(exc),
+            },
+        )
+
+    if not isinstance(payload, dict):
+        return JSONResponse(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            content={
+                "error": "invalid_payload",
+                "detail": "JSON payload must be an object.",
+            },
+        )
+
+    try:
+        raw_cdr = parse_raw_cdr(payload)
+
+    except CDRProcessingError as exc:
+        return JSONResponse(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            content={
+                "error": exc.reason.value,
+                "detail": exc.detail,
+                "failed_field": exc.failed_field,
+            },
+        )
+
+    return JSONResponse(
+        status_code=status.HTTP_202_ACCEPTED,
+        content={
+            "status": "accepted",
+            "raw_id": raw_cdr.raw_id,
+        },
+    )
diff --git a/tests/integration/test_ingestion_api.py b/tests/integration/test_ingestion_api.py
new file mode 100644
index 0000000..385c013
--- /dev/null
+++ b/tests/integration/test_ingestion_api.py
@@ -0,0 +1,131 @@
+from fastapi.testclient import TestClient
+
+from core.api.main import app
+
+
+client = TestClient(app)
+
+
+def valid_payload() -> dict:
+    return {
+        "raw_id": "raw-test-001",
+        "src_ip": "10.240.12.1",
+        "device_id": "310410998877665",
+        "caller_num": "0019875551234",
+        "svc": "4G_DATA",
+        "up_bytes": 1048576,
+        "down_bytes": 4194304,
+        "rat": 6,
+        "lac": "4021",
+        "ci": "8812",
+        "epoch_start": 1789900000,
+        "epoch_end": 1789900300,
+    }
+
+
+def test_health_endpoint() -> None:
+    response = client.get("/health")
+
+    assert response.status_code == 200
+    assert response.json() == {
+        "status": "ok",
+    }
+
+
+def test_valid_cdr_returns_202() -> None:
+    payload = valid_payload()
+
+    response = client.post(
+        "/api/v1/cdr/raw",
+        json=payload,
+    )
+
+    assert response.status_code == 202
+
+    assert response.json() == {
+        "status": "accepted",
+        "raw_id": "raw-test-001",
+    }
+
+
+def test_missing_required_field_returns_400() -> None:
+    payload = valid_payload()
+    del payload["caller_num"]
+
+    response = client.post(
+        "/api/v1/cdr/raw",
+        json=payload,
+    )
+
+    assert response.status_code == 400
+
+    body = response.json()
+
+    assert body["error"] == "missing_required_field"
+    assert body["failed_field"] == "caller_num"
+
+
+def test_invalid_rat_returns_400() -> None:
+    payload = valid_payload()
+    payload["rat"] = 99
+
+    response = client.post(
+        "/api/v1/cdr/raw",
+        json=payload,
+    )
+
+    assert response.status_code == 400
+
+    body = response.json()
+
+    assert body["error"] == "invalid_rat_value"
+    assert body["failed_field"] == "rat"
+
+
+def test_invalid_epoch_returns_400() -> None:
+    payload = valid_payload()
+
+    payload["epoch_start"] = 200
+    payload["epoch_end"] = 100
+
+    response = client.post(
+        "/api/v1/cdr/raw",
+        json=payload,
+    )
+
+    assert response.status_code == 400
+
+    body = response.json()
+
+    assert body["error"] == "invalid_epoch"
+
+def test_malformed_json_returns_400() -> None:
+    response = client.post(
+        "/api/v1/cdr/raw",
+        content='{"raw_id": invalid}',
+        headers={
+            "Content-Type": "application/json",
+        },
+    )
+
+    assert response.status_code == 400
+
+    body = response.json()
+
+    assert body["error"] == "invalid_json"
+
+def test_non_object_json_returns_400() -> None:
+    response = client.post(
+        "/api/v1/cdr/raw",
+        json=[
+            "not",
+            "a",
+            "cdr",
+        ],
+    )
+
+    assert response.status_code == 400
+
+    body = response.json()
+
+    assert body["error"] == "invalid_payload"