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William Lei
All work

FinFAST.ai: faster retrieval and cheaper AI for an economic research platform

A research platform where analysts query large economic datasets and read AI-written daily reports. I made it fast, made its AI answers more accurate, and cut what the AI cost to run.

Context
Built at Oxbridge Economics as main developer
Role
Main developer, full stack
When
2024 to 2026

Results

MeasureBeforeAfter
Typical data retrieval~10 s~1.5 s
Some queries~2 s0.5 s
Daily LLM token cost100%20%
RAG retrieval accuracybaseline+70%

The problem

Queries against large datasets took around 10 seconds, and some sources timed out entirely. The daily multi-agent report system was expensive to run, and the retrieval behind its answers often surfaced the wrong material.

What I did

  • Retrieval performance

    Consolidated chatty requests, indexed the MongoDB keys the queries actually filter on, optimized search, added caching, and paginated the APIs. Sources that used to time out now return in about 1.5 seconds.

  • Cheaper daily reports

    Owned the daily multi-agent economic-report system and restructured its data-collection prompts so the model provider's cache is reused, reducing daily token cost by 80%.

  • Better answers

    Redesigned the retrieval-augmented generation (RAG) algorithm behind research and discovery, improving retrieval accuracy by 70%.

  • Product and platform

    Built the FinAnalytics dataset-aware chat workspace, refined the DataHub dataset catalog, added Google sign-in, and deployed frontend and backend across AWS and Azure with CI/CD.

How it fits together

  1. 1

    Data sources

    Economic datasets, news, market feeds

  2. 2

    Pipelines

    Topic clouds, sentiment, scheduled collection

  3. 3

    Retrieval

    Indexed MongoDB, cache, paginated APIs: ~1.5 s

  4. 4

    AI layer

    RAG +70% accuracy, multi-agent reports −80% cost

  5. 5

    Web app

    Next.js workspace, Google OAuth, AWS + Azure

Stack

  • Next.js
  • React
  • TypeScript
  • Python
  • MongoDB
  • AWS Amplify, CloudFront, API Gateway, Lambda, EC2
  • DynamoDB / RDS
  • Azure AI Foundry, Cosmos DB

Have something similar in mind?

Book a 20-minute intro call, or write to william@wlei.org.

Book a 20-min intro call