TelosTax

TelosTax is a browser-based tax preparation app for the 2025 tax year, built on an open-source tax engine. It lists AI tax guidance, document import and deduction finding, and supports federal and state filing. The project reports more than 90 tax features intended to address about 85–90% of individual filers. Federal support includes Form 1040 with Schedules A–H, SE and D, plus more than 30 supplemental forms; state calculations are listed for all 50 states and Washington, DC. It also lists 41 IRS and 43 state PDF templates with mapped fields. Private Mode is described as fully offline. Optional AI tools use a user-supplied Anthropic API key, with personally identifiable information removed before transmission. Tax data is described as encrypted at rest with AES-256-GCM, and the calculation layer is described as having no database access or network calls. The project is free and open source; the maker does not publish plan prices.

TelosTax combines federal and state preparation with document tools and an offline mode. Its stated coverage is for tax year 2025, so confirm that scope fits your filing needs.

TelosTax is aimed at individual filers preparing 2025 federal and state returns. Its optional AI features suit users who can supply their own Anthropic API key.

TelosTax is a browser-based tax-preparation app for individual filers who want open-source software and an offline option. Its breadth of forms, state calculations and document tools make it worth considering for a 2025 return, but the year-specific scope is a firm boundary.

Overview

TelosTax is built around Form 1040, Schedules A–H, SE and D, and more than 30 supplemental forms. The project reports calculations for all 50 states and Washington, DC, and says its 90-plus tax features are intended to cover about 85–90% of individual filers. That is a substantial intended range, but it does not ensure that an unusual return or every filer’s circumstances are supported.

The published federal scope is tax year 2025. Filers preparing a return for a different year should choose another service rather than assume the same coverage applies. TelosTax is powered by an open-source tax engine from Telos News and is released under an MIT license, which will appeal to users who value inspectable, reusable software.

Key features

Forms and calculation traceability

TelosTax lists 41 IRS PDF templates and 43 state templates with field mapping that can populate forms. It also says calculations are traceable to authorities such as the Internal Revenue Code, Treasury Regulations, Revenue Procedures and IRS form instructions. That combination is useful for filers who want to follow how a result connects to tax rules; it is not a substitute for confirming that a particular return falls within the supported scope.

The maker describes the calculation layer as a standalone pure-function library without database access or network calls. It reports more than 6,100 tests across 139 test files. Those design and testing details suggest an emphasis on a bounded calculation engine, though they do not establish that every possible tax situation is covered.

AI and document tools

AI tax guidance, document import and deduction finding address common preparation tasks: getting help with tax questions, bringing in paperwork and identifying possible deductions. They are useful additions for filers who want those tasks in one app, but the AI features are optional rather than a requirement for using the tax engine.

Privacy and offline use

Private Mode is described as fully offline, and the app is described as installable and offline-capable on desktop and mobile. Users who prioritize keeping preparation work off a network may find that a meaningful advantage. Optional BYOK Mode uses the taxpayer’s own Anthropic API key for AI chat, expense scanning and document extraction; TelosTax says it strips personally identifiable information before transmission. Tax data is stated to be encrypted at rest with AES-256-GCM. Users should weigh the online AI workflow against the offline mode and their comfort with supplying an API key.

Pricing

TelosTax’s Free plan costs nothing and is a free, open-source tax-preparation app for tax year 2025. It includes AI tax guidance and deduction finding, with optional AI features requiring the user’s Anthropic API key. The free offering is a strong fit for individual filers whose return fits the 2025 scope and who are comfortable with an open-source app. The maker publishes no paid plan prices, so readers seeking a priced upgrade or a different level of service should compare other options.

Platforms

TelosTax supports Android, iOS, Linux, macOS, web and Windows. The browser-based app and installable desktop and mobile availability give users several ways to access it, including an offline-capable setup.

Who it's for

TelosTax is best suited to individual taxpayers filing for 2025 who want federal and state preparation, document tools and the option to work offline. It is a weaker fit for anyone filing for another tax year, or whose circumstances fall outside the project’s intended coverage. Filers who prefer not to use an open-source project or supply their own API key for AI tools may also prefer a different service.

Pros and cons

• Pros: Broad stated form and state-calculation coverage gives many individual filers a potentially useful starting point.
• Pros: Offline Private Mode and an offline-capable app suit users who want to prepare without relying on a network connection.
• Pros: Form templates and legal traceability can help users connect calculations to tax forms and authorities.
• Cons: Federal support is specified for 2025, which rules it out for returns from other tax years.
• Cons: Optional AI tools depend on the user providing an Anthropic API key, adding setup and a third-party service to those workflows.
• Cons: The stated coverage target is not a guarantee that an individual return’s full circumstances are supported.

Alternatives

AI Tax Software is a useful place to compare other AI-focused tax tools. Choose H&R Block Online instead if a simple tax situation fits its free online plan; it supports Form 1040 and charges per state filed. Taxfix is another option for individual filers, with an annual Basic plan priced at €39.99 a year and a return that is free until submission. For a free basic tier capped at ₹12 lakh total income and one app connection, consider Quicko.

EZTax offers a self-service ITR filing plan priced at ₹249 a month. TaxTim is an alternative tax-preparation service. Keeper may suit users seeking expense discovery, deduction summaries and an AI tax assistant; its Standard plan is $199 a year. Bart is another alternative. FlyFin offers a Premium plan at $29 a year, billed annually, for personal taxes.

Verdict

Choose TelosTax if you are an individual filing for tax year 2025 and value open-source software, broad stated federal and state coverage, and an offline preparation mode. Its strongest reason to choose it is the combination of form support, traceable calculations and flexible privacy modes in a free app. Look elsewhere if you need another tax year, need assurance that a specialized return is supported, or would rather use AI tools without bringing your own API key.