
ProjectionLab
Boldin
CoastFIRE Hub
fjordFIRE
Empower.me
Financial Toolbelt
FIRE Tracker
Calculate your path to financial independence

The modern platform for creating, sharing, and collaborating on AI prompts. Advanced version control and real-time testing.

Website, pricing, platforms and company facts side by side.
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| Website | firenum.com | diffyn.com |
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| Company | Startup from the United States · 1 - 9 employees · 2019 | — |
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In their own words, as submitted to SaaSHub.


Free FIRE calculator suite for planning early retirement. Calculate your FIRE number, Coast FIRE, Lean/Fat/Barista FIRE, project retirement dates, and track net worth with the Progress Tracker. Project your journey twoards FIRe on a dashboard. Model market crash scenarios and other events....
No description of Diffyn yet.
What each product offers, as listed by its team.


An editorial look at what each product does well and who it suits.


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The Ultimate Prompt Tool for Creators – Visualize & Organize with Diffyn
How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing Firenum and Diffyn.
Firenum's answer
Firenum plans your finances month by month and runs entirely in your browser, with no account and no signup. Your plan is stored on your own device, not on our servers. You get Monte Carlo simulation, historical backtesting against every period since 1871, and six stress scenarios (market crash, lower returns, job loss, expense spike, high inflation, retiring earlier or later), all for free. It supports 9 currencies with local number formatting, including lakh/crore for rupees and 万/億 for yen.
Diffyn's answer:
Addresses workflow and change management on LLM prompts, provide teams with traceability and visualization of tests across multiple models, provide deeper understading into efficiency of these prompts.
Firenum's answer
Paid planners like ProjectionLab and Boldin keep features such as saving your plan or advanced drawdown modelling behind a subscription. Firenum includes all of it free, with no account. Choose it if you want serious FIRE planning without handing your financial details to a company, or if you plan in a currency other than USD. If you need detailed US tax modelling or Roth conversion planning, a paid tool may still suit you better.
Diffyn's answer:
Diffyn is the platform that specializes on both change management and multi-model analysis.
Firenum's answer
Astro, Preact with Preact Signals, TypeScript, Chart.js, Web Workers (simulations run off the main thread), Cloudflare Workers for hosting, and Playwright for end-to-end tests. The backtesting uses Robert Shiller's historical S&P 500 data.
Diffyn's answer:
React, Next.js, POSTGRESQL
Firenum's answer
People working towards financial independence and early retirement (FIRE), from those who've just learned the 4% rule to those checking a drawdown plan before quitting. Many users are outside the US and want a planner that isn't built around US assumptions.
Diffyn's answer:
Professionals incorporating LLMs or AI tools in their workflow and wants to keep track of changes and test their prompts.
Firenum's answer
Firenum started as a single FIRE number calculator ("fire + num = your number") and grew into a full planner. The aim was to make FIRE planning free and private, and to say honestly when a fee-only advisor is worth paying for.
Diffyn's answer:
I started working on Diffyn when I notice that prompting has become an essential part of work across many industries. While there are version control platofrms like github, they are not designed for just prompt management are can be overkill such applications, it is also not integrated natively with various LLMs and relevant tools for users to validate ideas and visualise results properly.
Firenum's answer
Individual FIRE planners worldwide (no accounts, no data collected)
Share your experience with using Firenum and Diffyn. For example, how are they different and which one is better?
When comparing Firenum and Diffyn, you can also consider the following products.

The best retirement planning tool, FIRE calculator, and financial planning software built by, and for, the financial independence community.
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Short Description | Free FIRE calculator toolkit — Coast, Barista, Fat, and Lean FIRE numbers in seconds.
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Privacy-first FIRE planning for expats and money that crosses borders. Multi-currency by default, with FX attribution, per-member FI for couples, and relocation on real cost of living. No bank logins, no data sold. Made in Oslo, Norway. Free.
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