Quartzite is an advanced chat interface unifying access to more than 10 language models including Claude Opus 4.5, GPT-5.1 and Gemini 3, built around serious prompt engineering: a Markdown prompt editor with draft saving, version history for prompt iterations, token usage and cost estimation before running a prompt, a custom template library, automated prompt optimization, and CSV variable import for batch runs.
Bring-your-own-API-key pricing, transparently stated ($3.99/month subscription plus typically $2-3/month in your own actual API usage, rather than a marked-up all-inclusive price), is unusually honest for this category – a lot of multi-model chat wrappers obscure the real underlying API cost behind credits. Version history on prompts specifically, treating prompt iteration like a real engineering artifact, also serves a genuine workflow need for anyone doing serious prompt development rather than casual chat.
Requiring your own API keys means real technical setup compared to a fully hosted alternative, and total cost still scales with actual model usage regardless of the low subscription price – heavy use of frontier models adds up quickly on the API side even with an honest pricing structure. Optional local-only storage supports users who want to keep prompts off Quartzite’s own servers entirely.
