5 tools, in alphabetical order (this isn't a ranking). Check each tool's commercial-use notes before you ship assets in a game.
| Tool | Free plan | Commercial use | API | MCP |
|---|---|---|---|---|
 Charisma.ai | Paid only | Commercial use allowed | Available | Unverified |
 Convai | Free plan | Commercial use allowed | Available | Connects to MCP servers |
 ElevenLabs | Free plan | Commercial on paid plans only | Available | Official MCP server |
 Gridly | Free trial or credits only | Commercial use unverified | Available | Community server only |
 Inworld AI | Free plan | Commercial use allowed | Available | Official MCP server |
Platform for building interactive stories and AI character conversations, with script flow tools and AI voices, published to web, VR or game engines via SDKs.
Verdict: For story-driven AI character conversations on pay-as-you-go credits; its terms assign input and output rights to the customer.
Conversational AI characters for games and virtual worlds: NPCs with voice, knowledge and actions.
Verdict: For conversational NPCs with a free tier to prototype on; its terms give you ownership of AI-generated content.
Text-to-speech, voices, sound effects and music generation; usable for NPC voice lines and SFX.
Verdict: For NPC voice lines and SFX; free-plan output is non-commercial, so a paid plan is required to ship.
Content and localisation platform with a game-localisation use case: spreadsheet-style grids for strings, AI translation with linguistic context, AI voiceover files and an API.
Verdict: For teams that want game strings, AI translation and voiceover files in one tool; there is no free plan, only a 14-day trial.
Realtime text-to-speech and LLM inference platform that can power voiced, interactive characters.
Verdict: For realtime TTS and LLM-driven characters on pay-as-you-go pricing; its terms assign outputs to you.