OpenTax by Invaro

Web · Windows · Mac · Linux · Self-hosted · API

Freedom report

Three barsScore 6.5

Free tierA free tier is on its own pricing page
Open codeNo open-source code on record
Runs widely4 of 6 device platforms
DocumentedPlans, terms and facts published

OpenTax by Invaro is ranked #3 of 33 in AI tax software on Freedom251. It runs on API, Linux, macOS, Self-hosted, Web, Windows. There is a free plan.

OpenTax by Invaro plans and pricing

All plans

Evaluation Free No expiry · 600 requests/hour anonymous or 6,000/hour with a key opentax.invaro.ai · 8 Oct 2026

Compared on AI tax software

Free plan: Yes
Taxpayer types: both
AI tax guidance: Yes
Document import: Yes
Filing support: both

Best OpenTax by Invaro alternatives

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The record

Purpose: OpenTax is a deterministic tax computation engine designed to work beneath AI agents.
Tax forms: It supports complete line sets for individual Form 1040, corporate Form 1120, and fiduciary Form 1041 returns.
State coverage: The maker says state coverage spans 29 states and is growing.
Citations and proofs: Tax rules include statutory citations and effective dates, and computations can return a Merkle-rooted proof for offline verification.
Document processing: A deterministic compiler converts W-2 and 1099 boxes and birth dates into engine facts.
Out-of-scope cases: When the corpus cannot answer, the engine refuses with a reason instead of estimating.
Integrations: The hosted MCP connector is presented for assistants, IDEs, agents, and automation platforms; named examples include Claude, ChatGPT, Cursor, n8n, Zapier, and Make.
Interfaces: The maker documents REST, MCP, and OpenAPI interfaces for the hosted service.
Local use: The maker offers an installable package combining an MCP server, CLI, and HTTP host, and says the HTTP server can be self-hosted.
Free evaluation: The evaluation plan is free with no expiry; anonymous calls are limited to 600 requests an hour and a key raises the allowance to 6,000.
Data handling: The docs say request facts are computed in memory and not stored; usage records retain limited metadata rather than request arguments.
Privacy telemetry: The privacy page says the hosted MCP endpoint does not store or log tax facts, while the CLI and MCP package send an anonymous usage ping that can be disabled.
License: The engine is offered under AGPL-3.0 with a commercial license also available.
Intended users: The maker describes use cases for tax and accounting firms, freelancers and S-corp clients, advisory engagements, and financial planners.
Price from: Free

Where it ranks on Freedom251

Best AI Tax Software in 2026#3 of 33

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Sources

opentax.invaro.ai· checked 8 Oct 2026
opentax.invaro.ai/docs· checked 8 Oct 2026
opentax.invaro.ai/privacy· checked 8 Oct 2026