Prompt Studio
Fan a prompt across providers, see streamed outputs side by side.
System (optional)
applies to all providers
Prompt
use {{var}} for substitution, {{var?}} for optional
Eval Bench
Score a dataset across providers with assertions or LLM-as-judge.
Prompt template
use {{input}} and {{expected}} substitutions
Assertions
scored against each provider's output
Providers
pick in Prompt Studio's provider row, then come back
idle
RAG Lab
Chunk → embed → retrieve → build context. Hand off to Studio for inference.
① Documents & chunking
② Embeddingsnot loaded
③ Retriever
Dense (cosine)
BM25
Hybrid (RRF)
④ Context builder0 chunks · 0 chars
Run history
Last 0 runs · stored in OPFS.
Models & Keys
Keys stay in this browser's localStorage. Test buttons hit each provider's models endpoint.
Providers
Model matrix
Pricing per 1K tokens · last refreshed 2026-05-15.
Rate-limit calculator
Given an RPM and per-call token budget, estimate throughput.
Settings
JS API
window.mantra
Cross-tab postMessage
Storage
Runs in OPFS
… ·
Clear local data
About
Mantra is part of the NakliTechie single-file browser-native series. Source: github.com/NakliTechie/Mantra