feat: add Postgres/Supabase backend for memory store

CHANGELOG.md

@@ -2,6 +2,14 @@
 
 All notable changes to Distill are documented here.
 
+## [Unreleased]
+
+### Added
+
+- **PostgreSQL/Supabase memory backend** — Persistent memory storage using Postgres instead of ephemeral SQLite. New `--memory-backend postgres` and `--memory-dsn` flags on `api` and `mcp` commands. Implements the same `Store` interface as SQLiteStore. ([#40](https://github.com/Siddhant-K-code/distill/pull/40))
+
+---
+
 ## [v0.4.0] - 2026-02-24
 
 ### Added

FAQ.md

@@ -22,7 +22,7 @@ LLMs are non-deterministic. The same input can produce different compressed outp
 
 ### What is Context Memory?
 
-Persistent memory that accumulates knowledge across agent sessions. Store context once, recall it later by semantic similarity + recency. Memories are deduplicated on write and compressed over time through hierarchical decay (full text → summary → keywords → evicted). Enable with `--memory` on the `api` or `mcp` commands.
+Persistent memory that accumulates knowledge across agent sessions. Store context once, recall it later by semantic similarity + recency. Memories are deduplicated on write and compressed over time through hierarchical decay (full text → summary → keywords → evicted). Enable with `--memory` on the `api` or `mcp` commands. Supports SQLite (default, local) and PostgreSQL/Supabase (`--memory-backend postgres`) for persistent storage.
 
 ### What are Sessions?
 

README.md

@@ -212,7 +212,16 @@ See [mcp/README.md](mcp/README.md) for more configuration options.
 
 Persistent memory that accumulates knowledge across agent sessions. Memories are deduplicated on write, ranked by relevance + recency on recall, and compressed over time through hierarchical decay.
 
-Enable with the `--memory` flag on `api` or `mcp` commands.
+Enable with the `--memory` flag on `api` or `mcp` commands. Supports SQLite (default, local) and PostgreSQL (persistent, recommended for production).
+
+```bash
+# SQLite (default - local file, good for development)
+distill api --memory
+
+# PostgreSQL (persistent - recommended for production/Supabase)
+distill api --memory --memory-backend postgres \
+  --memory-dsn 'postgres://user:pass@host:5432/db?sslmode=require'
+```
 
 ### CLI
 
@@ -273,8 +282,13 @@ Accessing a memory resets its decay clock. Configure ages via `distill.yaml`:
 
 ```yaml
 memory:
+  # SQLite (default)
   db_path: distill-memory.db
   dedup_threshold: 0.15
+
+  # Or PostgreSQL/Supabase
+  # backend: postgres
+  # dsn: postgres://user:pass@host:5432/db?sslmode=require
 ```
 
 ## Session Management
@@ -431,7 +445,9 @@ auth:
     - ${DISTILL_API_KEY}
 
 memory:
-  db_path: distill-memory.db
+  db_path: distill-memory.db       # SQLite (default)
+  # backend: postgres              # Use 'postgres' for Supabase/PostgreSQL
+  # dsn: ${DATABASE_URL}           # Postgres connection string
   dedup_threshold: 0.15
 
 session:
@@ -448,6 +464,7 @@ Environment variables can be referenced using `${VAR}` or `${VAR:-default}` synt
 OPENAI_API_KEY      # For text → embedding conversion (see note below)
 PINECONE_API_KEY    # For Pinecone backend
 QDRANT_URL          # For Qdrant backend (default: localhost:6334)
+DATABASE_URL        # For Postgres memory backend (Supabase connection string)
 DISTILL_API_KEYS    # Optional: protect your self-hosted instance (see below)
 ```
 

cmd/api.go

@@ -46,6 +46,8 @@ func init() {
 	apiCmd.Flags().String("embedding-model", "text-embedding-3-small", "OpenAI embedding model")
 	apiCmd.Flags().String("api-keys", "", "Comma-separated list of valid API keys (or use DISTILL_API_KEYS)")
 	apiCmd.Flags().Bool("memory", false, "Enable persistent memory store")
+	apiCmd.Flags().String("memory-backend", "sqlite", "Memory store backend: sqlite or postgres")
+	apiCmd.Flags().String("memory-dsn", "", "Memory store DSN (file path for sqlite, connection string for postgres)")
 	apiCmd.Flags().Bool("session", false, "Enable session management")
 	apiCmd.Flags().String("session-db", "distill-sessions.db", "SQLite database path for session store")
 
@@ -184,15 +186,23 @@ func runAPI(cmd *cobra.Command, args []string) error {
 	// Setup memory store (opt-in)
 	enableMemory, _ := cmd.Flags().GetBool("memory")
 	if enableMemory {
-		memDBPath := viper.GetString("memory.db_path")
-		if memDBPath == "" {
-			memDBPath = "distill-memory.db"
+		memBackend, _ := cmd.Flags().GetString("memory-backend")
+		memDSN, _ := cmd.Flags().GetString("memory-dsn")
+		// Fall back to config file values
+		if memDSN == "" {
+			memDSN = viper.GetString("memory.dsn")
+		}
+		if memDSN == "" {
+			memDSN = viper.GetString("memory.db_path")
+		}
+		if memBackend == "sqlite" && memDSN == "" {
+			memDSN = "distill-memory.db"
 		}
 		memThreshold := viper.GetFloat64("memory.dedup_threshold")
 		if memThreshold == 0 {
 			memThreshold = 0.15
 		}
-		memStore, err := memoryStoreFromConfig(memDBPath, memThreshold)
+		memStore, err := memoryStoreFromConfig(memBackend, memDSN, memThreshold)
 		if err != nil {
 			return fmt.Errorf("failed to create memory store: %w", err)
 		}

cmd/api_memory.go

@@ -13,7 +13,7 @@ import (
 
 // MemoryAPI handles memory-related HTTP endpoints.
 type MemoryAPI struct {
-	store    *memory.SQLiteStore
+	store    memory.Store
 	embedder retriever.EmbeddingProvider
 }
 

cmd/mcp.go

@@ -92,7 +92,9 @@ func init() {
 
 	// Memory store
 	mcpCmd.Flags().Bool("memory", false, "Enable persistent memory store")
-	mcpCmd.Flags().String("memory-db", "distill-memory.db", "SQLite database path for memory store")
+	mcpCmd.Flags().String("memory-backend", "sqlite", "Memory store backend: sqlite or postgres")
+	mcpCmd.Flags().String("memory-dsn", "", "Memory store DSN (file path for sqlite, connection string for postgres")
+	mcpCmd.Flags().String("memory-db", "distill-memory.db", "SQLite database path for memory store (deprecated, use --memory-dsn)")
 	mcpCmd.Flags().Bool("session", false, "Enable session management")
 	mcpCmd.Flags().String("session-db", "distill-sessions.db", "SQLite database path for session store")
 
@@ -108,7 +110,7 @@ type MCPServer struct {
 	broker    *contextlab.Broker
 	embedder  retriever.EmbeddingProvider
 	cfg       contextlab.BrokerConfig
-	memStore  *memory.SQLiteStore
+	memStore  memory.Store
 	sessStore *session.SQLiteStore
 }
 
@@ -159,10 +161,12 @@ func runMCP(cmd *cobra.Command, args []string) error {
 	// Create memory store (opt-in)
 	enableMemory, _ := cmd.Flags().GetBool("memory")
 	if enableMemory {
-		memDBPath, _ := cmd.Flags().GetString("memory-db")
-		memCfg := memory.DefaultConfig()
-		memCfg.DedupThreshold = threshold
-		memStore, err := memory.NewSQLiteStore(memDBPath, memCfg)
+		memBackend, _ := cmd.Flags().GetString("memory-backend")
+		memDSN, _ := cmd.Flags().GetString("memory-dsn")
+		if memDSN == "" {
+			memDSN, _ = cmd.Flags().GetString("memory-db")
+		}
+		memStore, err := memoryStoreFromConfig(memBackend, memDSN, threshold)
 		if err != nil {
 			return fmt.Errorf("failed to create memory store: %w", err)
 		}

cmd/memory.go

@@ -250,11 +250,22 @@ func runMemoryStats(cmd *cobra.Command, args []string) error {
 
 // memoryStoreFromConfig creates a memory store from the API server config.
 // Used by the API server and MCP server.
-func memoryStoreFromConfig(dbPath string, threshold float64) (*memory.SQLiteStore, error) {
-	if dbPath == "" {
-		dbPath = "distill-memory.db"
-	}
+// backend: "sqlite" (default) or "postgres"
+// dsn: database path (sqlite) or connection string (postgres)
+func memoryStoreFromConfig(backend, dsn string, threshold float64) (memory.Store, error) {
 	cfg := memory.DefaultConfig()
 	cfg.DedupThreshold = threshold
-	return memory.NewSQLiteStore(dbPath, cfg)
+
+	switch backend {
+	case "postgres":
+		if dsn == "" {
+			return nil, fmt.Errorf("--memory-dsn is required for postgres backend")
+		}
+		return memory.NewPostgresStore(dsn, cfg)
+	default:
+		if dsn == "" {
+			dsn = "distill-memory.db"
+		}
+		return memory.NewSQLiteStore(dsn, cfg)
+	}
 }

go.mod

@@ -39,6 +39,10 @@ require (
 	github.com/hashicorp/hcl v1.0.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/invopop/jsonschema v0.13.0 // indirect
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
+	github.com/jackc/pgx/v5 v5.8.0 // indirect
+	github.com/jackc/puddle/v2 v2.2.2 // indirect
 	github.com/magiconair/properties v1.8.10 // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
@@ -72,6 +76,7 @@ require (
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 // indirect
 	golang.org/x/net v0.49.0 // indirect
+	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/sys v0.40.0 // indirect
 	golang.org/x/term v0.39.0 // indirect
 	golang.org/x/text v0.33.0 // indirect

go.sum

@@ -42,6 +42,14 @@ github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/invopop/jsonschema v0.13.0 h1:KvpoAJWEjR3uD9Kbm2HWJmqsEaHt8lBUpd0qHcIi21E=
 github.com/invopop/jsonschema v0.13.0/go.mod h1:ffZ5Km5SWWRAIN6wbDXItl95euhFz2uON45H2qjYt+0=
+github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
+github.com/jackc/pgpassfile v1.0.0/go.mod h1:CEx0iS5ambNFdcRtxPj5JhEz+xB6uRky5eyVu/W2HEg=
+github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 h1:iCEnooe7UlwOQYpKFhBabPMi4aNAfoODPEFNiAnClxo=
+github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761/go.mod h1:5TJZWKEWniPve33vlWYSoGYefn3gLQRzjfDlhSJ9ZKM=
+github.com/jackc/pgx/v5 v5.8.0 h1:TYPDoleBBme0xGSAX3/+NujXXtpZn9HBONkQC7IEZSo=
+github.com/jackc/pgx/v5 v5.8.0/go.mod h1:QVeDInX2m9VyzvNeiCJVjCkNFqzsNb43204HshNSZKw=
+github.com/jackc/puddle/v2 v2.2.2 h1:PR8nw+E/1w0GLuRFSmiioY6UooMp6KJv0/61nB7icHo=
+github.com/jackc/puddle/v2 v2.2.2/go.mod h1:vriiEXHvEE654aYKXXjOvZM39qJ0q+azkZFrfEOc3H4=
 github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
 github.com/juju/gnuflag v0.0.0-20171113085948-2ce1bb71843d/go.mod h1:2PavIy+JPciBPrBUjwbNvtwB6RQlve+hkpll6QSNmOE=
 github.com/k0kubun/go-ansi v0.0.0-20180517002512-3bf9e2903213/go.mod h1:vNUNkEQ1e29fT/6vq2aBdFsgNPmy8qMdSay1npru+Sw=
@@ -119,6 +127,7 @@ github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSS
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/8L+MA=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
@@ -165,6 +174,8 @@ golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 h1:mgKeJMpvi0yx/sU5GsxQ7p6s2
 golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546/go.mod h1:j/pmGrbnkbPtQfxEe5D0VQhZC6qKbfKifgD0oM7sR70=
 golang.org/x/net v0.49.0 h1:eeHFmOGUTtaaPSGNmjBKpbng9MulQsJURQUAfUwY++o=
 golang.org/x/net v0.49.0/go.mod h1:/ysNB2EvaqvesRkuLAyjI1ycPZlQHM3q01F02UY/MV8=
+golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
+golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.40.0 h1:DBZZqJ2Rkml6QMQsZywtnjnnGvHza6BTfYFWY9kjEWQ=