Bring your NPCs to life.
A Rust runtime for game NPCs — conversations, quests, inventory, and beliefs — exposed through a stable C ABI that works with any engine.
Freeform dialogue
Replace rigid dialogue trees with real back-and-forth. Players drive the topic; NPCs stay consistent with lore and personality instead of offering three canned replies.
Quests
Write quests as step graphs. NPCs drop the right hints at the right time, and steps advance on what's said in conversation or on items changing hands — no dialogue parsing in your game.
Inventory
NPCs know what they carry and what you're visibly holding. They offer and ask for items in their own words; your game decides what changes hands, and they remember every trade.
Beliefs
NPCs believe things about players and each other — who carries what, who they owe, what faith a stranger keeps. Seed their assumptions, and let them be wrong.
Universal C ABI
One shared library. Unity, Unreal, Godot, custom engines — if it can call C functions, it can use Animist.
Memory Safe
Built in Rust with panic catching at the FFI boundary. No undefined behavior leaking into your game.
Zero Dependencies
Link a single static or dynamic library. No runtime to install, no package manager, no framework lock-in. On Linux the library uses the system's OpenSSL 3 (libssl.so.3), which most current distributions already include.
Clean Handle API
Opaque handles with status codes. Familiar patterns for anyone who's integrated a C library before.
NPC memory
Rolling summarization keeps long conversations coherent, and export/import lets you persist and restore dialogue with your saves.
A conversation in a few lines of C
const char* config = "{ \"license_token\": \"…\", \"api_key\": \"…\" }";
AnimistRuntimeHandle* runtime = NULL;
animist_runtime_create(config, &runtime);
uint64_t player_id = 1, char_id = 100;
animist_character_register(runtime, char_id, "{ \"name\": \"Merchant\" }", false);
uint64_t conv_id;
animist_conversation_begin(runtime, player_id, char_id, &conv_id);
AnimistResponseHandle* response = NULL;
animist_conversation_send_message(
runtime, conv_id, char_id, "Merchant",
player_id, "Do you sell potions?", &response);
char* text = NULL;
animist_response_get_text(response, &text);
printf("%s\n", text);
animist_string_free(text);
animist_response_destroy(response);
animist_runtime_destroy(runtime);Config JSON carries your developer license token and your LLM provider's API key (OpenAI by default; leave the key out and the NPC gives placeholder replies while you wire things up). Create a runtime, register a character, start a conversation, send messages, read responses. Same pattern in C#, C++, Python, or any FFI-capable language — see the full C ABI docs for status codes, JSON payloads, and memory rules.
See it running right now
This site is itself a consumer of the Animist C ABI, loaded via Node.js FFI.
The demo page talks to a real AnimistRuntime through the same
shared library your game would link—try freeform NPC chat there, not just preset dialogue lines.
Integrating the C ABI in your game? Request a free developer license (email in, signed token out, verified offline; games you ship never expire). Questions? Reach us at support@animistnpc.com.
Open the Demo