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open-fintech-builders

open-fintech-builders
@openfi-builders • Created Sep 2025 • Open Source
38 posts • 148 reactions • 67 comments
Open-finance builders: fintech, DeFi, blockchain & crypto, cryptography, inclusive tools. Share code, research & launch.
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Posted in open-fintech-builders group
Pocket Portfolioverified • Apr 1 • in Articles • 2 min read
Sovereign Intelligence: The Complete 25,000 Word Blueprint (Download)
Sovereign Intelligence: The Complete 25,000 Word Blueprint Download This 12-part series has walked through the full architecture of Pocket Analyst—the local-first financial AI that keeps your data on your device and sends only a sanitized snapshot ...
post-cover-11982
4 Reactions 1 Comments
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Pocket Portfolioverified • Mar 30 • in Articles • 2 min read
Open Sourcing our Financial System Prompts (Code Dump)
Open Sourcing our Financial System Prompts Code Dump This post gives implementers a high-signal reference: system prompt structure, key functions, and file paths. The why matters as much as the what. System prompt outline minimal 1 Role: "You are...
post-cover-11981
0 Reactions 0 Comments
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Pocket Portfolioverified • Mar 25 • in Articles • 2 min read
The Roadmap: Moving from AI Chatbots to Autonomous Financial Agents
The Roadmap: Moving from AI Chatbots to Autonomous Financial Agents Today: user asks, model answers. Tomorrow: user asks, model proposes an action e.g. "Add AAPL to watchlist" and the user confirms. The roadmap: confirmation UI, audit log, no auton...
post-cover-11980
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Pocket Portfolioverified • Mar 24 • in Articles • 2 min read
The Future of Finance is Client-Side AI
The Future of Finance is Client-Side AI Many fintech products lock data in their own APIs and dashboards. Universal Import is a step toward user-owned data: the user exports, holds, and imports; the app is a tool that runs on their data. From SaaS...
post-cover-11444
3 Reactions 1 Comments
Posted in open-fintech-builders group
Pocket Portfolioverified • Mar 23 • in Articles • 1 min read
Flash vs. GPT-4o: Benchmarking latency for financial reasoning
Flash vs. GPT-4o: Benchmarking latency for financial reasoning We benchmarked Gemini Flash, Pro vs. OpenAI e.g. GPT-4o for financial Q&A. Criteria: latency, quality of financial reasoning, grounding support, cost, and privacy data handling. Gemini ...
post-cover-11979
6 Reactions 1 Comments
Posted in open-fintech-builders group
Pocket Portfolioverified • Mar 19 • in Articles • 1 min read
Beyond Finance: Use Cases for Client-Side ETL
Beyond Finance: Use Cases for Client-Side ETL Any source that can export CSV can be supported. The same pipeline applies; only the header vocabulary and locale may differ. Brokers, banks, crypto, tax tools Traditional brokers US/UK/EU, banks, cry...
post-cover-11443
7 Reactions 1 Comments
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Pocket Portfolioverified • Mar 18 • in Articles • 1 min read
Economic Modeling: Running a free AI tier without going bankrupt
Economic Modeling: Running a free AI tier without going bankrupt Gemini Flash free tier: low cost per token; suitable for most portfolio and market questions. Gemini Pro paid: higher capability and cost; for power users. We estimate cost per query ...
post-cover-11978
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Pocket Portfolioverified • Mar 17 • in Articles • 1 min read
Security & Threat Modeling for Local Apps
Security & Threat Modeling for Local Apps Full CSV never touches your server. Here's what the design guarantees—and how we mitigate the rest. What is never transmitted by design Full CSV: Never sent to the server. Only headers and a small sample ...
post-cover-11442
4 Reactions 2 Comments
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Pocket Portfolioverified • Mar 16 • in Articles • 2 min read
Building Tactile AI: Optimistic UI and the Vercel AI SDK
Building Tactile AI: Optimistic UI and the Vercel AI SDK The feeling of "someone is typing"—streaming tokens, optimistic UI updates, clear loading states—makes the assistant feel responsive. We use Vercel AI SDK streamText, useChat for consistent s...
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Pocket Portfolioverified • Mar 12 • in Articles • 1 min read
Comparison: Universal Import vs. Plaid/Yodlee
Comparison: Universal Import vs. Plaid/Yodlee Plaid and broker APIs give real-time data—and a long-term liability. Here's how Universal CSV import compares. | Dimension | Universal LLM Import CSV | Plaid / Broker APIs | |--...
post-cover-11441
2 Reactions 1 Comments
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Pocket Portfolioverified • Mar 11 • in Articles • 2 min read
Transient File I/O: Parsing massive CSVs in the browser without server storage
Transient File I/O: Parsing massive CSVs in the browser without server storage The user can drop a CSV or text file into the chat to ask "analyze this" or "what do you see?" We parse the file in the browser e.g. with PapaParse, extract text or a ta...
post-cover-11976
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Pocket Portfolioverified • Mar 10 • in Articles • 1 min read
The Interface of Uncertainty: Designing Human-in-the-Loop
The Interface of Uncertainty: Designing Human-in-the-Loop When the heuristic or LLM isn't confident, we don't guess. We show the mapping UI and let the user confirm or correct. That's REQUIRESMAPPING—the interface of uncertainty. Production touchp...
post-cover-11440
6 Reactions 2 Comments
Posted in open-fintech-builders group
Pocket Portfolioverified • Mar 9 • in Articles • 2 min read
Prompt Guardrails: Forcing an LLM to only talk about finance
Prompt Guardrails: Forcing an LLM to only talk about finance The system prompt defines who the assistant is and what it can do. We use a prompt that constrains the assistant to finance, investing, markets, and economic data. It states: "You are the...
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Pocket Portfolioverified • Mar 5 • in Articles • 1 min read
Google Drive as Dumb Storage
Google Drive as Dumb Storage Google Drive isn't your backend. We use it as file storage for a single export file. The app creates/updates that file and can read it back. Drive does not run business logic, validation, or schema—it's "a folder in the...
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Posted in open-fintech-builders group
Pocket Portfolioverified • Mar 5 • in Articles • 2 min read
AI Grounding: Connecting local data to live stock prices using Gemini 1.5
AI Grounding: Connecting local data to live stock prices using Gemini 1.5 Users ask "What's the current price of AAPL?" or "Any news on TSLA?" The model must not guess; it must use live, authoritative data. Gemini's native grounding e.g. Google Sea...
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Pocket Portfolioverified • Mar 3 • in Articles • 1 min read
Data Normalization: Solving the Date/Locale Nightmare
Data Normalization: Solving the Date/Locale Nightmare 03/04/2024 is March 4 in the US and April 3 in the UK. Get the locale wrong and you silently corrupt trade dates. We make locale explicit and use deterministic, locale-aware parsers for every va...
post-cover-11438
5 Reactions 1 Comments
Posted in open-fintech-builders group
Pocket Portfolioverified • Mar 2 • in Articles • 2 min read
The Context Engine: Squashing 10,000 trades into 4,000 tokens
The Context Engine: Squashing 10,000 trades into 4,000 tokens The context engine is the code that maps the user's portfolio state to a string the LLM can use. In our implementation it is a single function: buildPortfolioContexttrades, positions in ...
post-cover-11973
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Pocket Portfolioverified • Feb 26 • in Articles • 1 min read
The 3-Row Snapshot: Privacy-Preserving Inference
The 3-Row Snapshot: Privacy-Preserving Inference Sending the full CSV to an API would be a privacy and cost disaster. We send only headers and three sample rows. That's enough for the model to infer which column is date, ticker, quantity, price—wit...
post-cover-11437
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Posted in open-fintech-builders group
Pocket Portfolioverified • Feb 25 • in Articles • 3 min read
Architecting a Local-First Hybrid RAG for Finance
Architecting a Local-First Hybrid RAG for Finance Server: Next.js App Router, Vercel AI SDK streamText, useChat, Gemini 1.5 Flash default and optional Pro for paid tiers. The API route /api/ai/chat is the gatekeeper: it receives sanitized context,...
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Welcome to open-fintech-builders — by Pocket Portfolio


We started Pocket Portfolio because a lot of finance UX felt like a locked room: opaque numbers, dead-ends, and “0.00” when you needed truth. We wanted the opposite—explainable systems you can model, test, and trust. This group is the workshop where we build that kind of internet finance together.


What this space is


A hands-on hub for engineers, designers, and researchers shipping at the edge of fintech, DeFi, cryptography, and open finance. Come here to sketch architectures, argue (kindly) about failure policies, and turn paper ideas into shipped slices.


Our design & tech north stars


  • Explainable > Magical — every number should say why it changed.

  • Keyboard-first = fast — a11y that doubles as speed (grids, shortcuts, roving tabindex).

  • Client → Edge Resilience — timeouts, retries, last-known-good; never show 0.00.

  • Local-first where it matters — scenarios and recent quotes cached on device; privacy by default.

  • Small Slices, Shipped Often — testable diffs beat perfect decks.


What to post (prefix with tags)


  • [DISCUSS] Architecture, DX, a11y patterns, edge/runtime trade-offs.

  • [RFD/RFC] Specs worth breaking: price fallbacks, wallet flows, import pipelines.

  • [LAUNCH] OSS releases, demos, playgrounds, design tokens, Figma kits.

  • [HELP] Debug threads with a minimal repro (gist/repo, redacted data).

  • [REVIEW] “Tear down my modal/interaction/state machine” — we give actionable notes.

  • [LEARN] Paper notes (ZK/Schnorr/MPC/AA), threat models, failure post-mortems.


Weekly rituals


  • Ship Friday — post one screenshot/GIF or diff you shipped this week.

  • Spec Clinic (Wed) — 30-min async review of a single RFD/RFC.

  • Paper Club (Sat) — one cryptography/DeFi paper; five bullets, one diagram.


Starter threads (jump in)


  1. Introductions — stack, timezone, what you’re building.

  2. Resilient Quotes — client→edge fallback designs that never show 0.00.

  3. Import Lab — broker CSV mappings (share one redacted row + expected schema).

  4. Mock-Trade UX — “are we sure?” layer patterns and keyboard accessibility.

  5. Wallet UX & Security — MPC/AA, seedless recovery, signing flows, threat models.


House rules (non-commercial)


  • OSS and learning first. No token pumps, price calls, or affiliate shills.

  • If you represent a company/protocol, disclose and keep it educational.

  • No investment advice. We ship software, research, and design.

  • Be kind; cite sources; prefer reproducible examples; celebrate small wins.


Pocket Portfolio (why we’re here)


We’re building an open-source, no-paywall investing dashboard: CSV → clean live P/L → Mock-Trade & Scenario Lab. We’ll share architecture notes, a11y patterns, and failure policies as we ship.


  • App: pocketportfolio.app/app

  • Repo: github.com/PocketPortfolio/Financialprofilenetwork

  • Build in public: dev.to/pocketportfolio


This is a forum, not a chat: keep updates in your thread (bump with progress), and help one another reach first useful insight in under a minute. Welcome aboard.