diff --git a/ingestion/internal/api/handler.go b/ingestion/internal/api/handler.go
new file mode 100644
index 0000000..631710c
--- /dev/null
+++ b/ingestion/internal/api/handler.go
@@ -0,0 +1,96 @@
+// ingestion/internal/api/handler.go
+package api
+
+import (
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/search"
+)
+
+// Handler serves the ingestion HTTP API.
+type Handler struct {
+	brainDir string
+	logger   *slog.Logger
+}
+
+// NewHandler constructs a Handler. brainDir is the absolute path to brain/.
+func NewHandler(brainDir string, logger *slog.Logger) *Handler {
+	return &Handler{brainDir: brainDir, logger: logger}
+}
+
+type queryRequest struct {
+	Query  string `json:"query"`
+	Domain string `json:"domain,omitempty"`
+	Limit  int    `json:"limit,omitempty"`
+}
+
+type writeRequest struct {
+	Content  string `json:"content"`
+	Filename string `json:"filename,omitempty"`
+}
+
+// Query handles POST /query — full-text search across the brain wiki.
+func (h *Handler) Query(w http.ResponseWriter, r *http.Request) {
+	var req queryRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, "invalid JSON", http.StatusBadRequest)
+		return
+	}
+	if req.Limit == 0 {
+		req.Limit = 5
+	}
+
+	results, err := search.Query(h.brainDir, req.Query, req.Limit)
+	if err != nil {
+		h.logger.Error("query failed", "err", err)
+		http.Error(w, "search error", http.StatusInternalServerError)
+		return
+	}
+
+	writeJSON(w, map[string]any{"results": results})
+}
+
+// Write handles POST /write — write raw content to brain/raw/.
+func (h *Handler) Write(w http.ResponseWriter, r *http.Request) {
+	var req writeRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, "invalid JSON", http.StatusBadRequest)
+		return
+	}
+	if req.Content == "" {
+		http.Error(w, "content is required", http.StatusBadRequest)
+		return
+	}
+
+	filename := req.Filename
+	if filename == "" {
+		filename = fmt.Sprintf("%s-auto.md", time.Now().UTC().Format("2006-01-02-150405"))
+	}
+
+	rawDir := filepath.Join(h.brainDir, "raw")
+	if err := os.MkdirAll(rawDir, 0o755); err != nil {
+		http.Error(w, "failed to create raw dir", http.StatusInternalServerError)
+		return
+	}
+
+	dest := filepath.Join(rawDir, filepath.Base(filename))
+	if err := os.WriteFile(dest, []byte(req.Content), 0o644); err != nil {
+		h.logger.Error("write failed", "err", err)
+		http.Error(w, "write error", http.StatusInternalServerError)
+		return
+	}
+
+	rel, _ := filepath.Rel(h.brainDir, dest)
+	writeJSON(w, map[string]string{"path": filepath.ToSlash(rel)})
+}
+
+func writeJSON(w http.ResponseWriter, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(v) //nolint:errcheck
+}
diff --git a/ingestion/internal/api/handler_test.go b/ingestion/internal/api/handler_test.go
new file mode 100644
index 0000000..e153c0a
--- /dev/null
+++ b/ingestion/internal/api/handler_test.go
@@ -0,0 +1,83 @@
+// ingestion/internal/api/handler_test.go
+package api_test
+
+import (
+	"bytes"
+	"encoding/json"
+	"log/slog"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func setup(t *testing.T) (string, *api.Handler) {
+	t.Helper()
+	dir := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki", "concepts"), 0o755))
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw"), 0o755))
+	require.NoError(t, os.WriteFile(
+		filepath.Join(dir, "wiki", "concepts", "tdd.md"),
+		[]byte("---\ntitle: TDD\ndomain: software\n---\n\nTest-driven development is a discipline.\n"),
+		0o644,
+	))
+	logger := slog.New(slog.NewTextHandler(os.Stderr, nil))
+	return dir, api.NewHandler(dir, logger)
+}
+
+func TestQuery_ReturnsResults(t *testing.T) {
+	_, h := setup(t)
+	body, _ := json.Marshal(map[string]any{"query": "test driven", "limit": 5})
+	req := httptest.NewRequest(http.MethodPost, "/query", bytes.NewReader(body))
+	rec := httptest.NewRecorder()
+
+	h.Query(rec, req)
+
+	assert.Equal(t, http.StatusOK, rec.Code)
+	var resp map[string]any
+	require.NoError(t, json.Unmarshal(rec.Body.Bytes(), &resp))
+	results := resp["results"].([]any)
+	assert.NotEmpty(t, results)
+}
+
+func TestWrite_CreatesRawFile(t *testing.T) {
+	dir, h := setup(t)
+	body, _ := json.Marshal(map[string]any{
+		"content":  "# Test note\n\nSome content.",
+		"filename": "test-note.md",
+	})
+	req := httptest.NewRequest(http.MethodPost, "/write", bytes.NewReader(body))
+	rec := httptest.NewRecorder()
+
+	h.Write(rec, req)
+
+	assert.Equal(t, http.StatusOK, rec.Code)
+	var resp map[string]string
+	require.NoError(t, json.Unmarshal(rec.Body.Bytes(), &resp))
+	assert.NotEmpty(t, resp["path"])
+
+	written := filepath.Join(dir, "raw", "test-note.md")
+	content, err := os.ReadFile(written)
+	require.NoError(t, err)
+	assert.Contains(t, string(content), "Some content.")
+}
+
+func TestWrite_GeneratesFilenameIfAbsent(t *testing.T) {
+	dir, h := setup(t)
+	body, _ := json.Marshal(map[string]any{"content": "auto name"})
+	req := httptest.NewRequest(http.MethodPost, "/write", bytes.NewReader(body))
+	rec := httptest.NewRecorder()
+
+	h.Write(rec, req)
+
+	assert.Equal(t, http.StatusOK, rec.Code)
+	entries, _ := os.ReadDir(filepath.Join(dir, "raw"))
+	assert.Len(t, entries, 1)
+	assert.True(t, strings.HasSuffix(entries[0].Name(), ".md"))
+}