Side by side

Hartigan RTI Pro vs Warp Tax Compliance

Both stand on payroll tax software. Which one you can start free with, which one lets you read the code, and what each costs once you pay.

Hartigan RTI Pro

Paid Windows

RTI Pro focuses on validating and filing pre-calculated payroll information through the Government Gateway. Confirm that your payroll system and employee band match its supported workflow and pricing.

Visit Hartigan RTI Pro

Warp Tax Compliance

Paid APIWeb

Warp Tax Compliance brings registrations, filings, payments, forms, and reconciliation into one service. Buyers should account for platform fees and choose a state-coverage tier that matches their payroll footprint.

Visit Warp Tax Compliance

The facts

	Hartigan RTI Pro	Warp Tax Compliance
Free plan	No	No
Open source	Not published	Not published
Runs on	Windows	API, Web
Lowest paid plan	RTI Pro — 1–10 employees: £230 a year	Starter: $35 a month
Plans published	10	3
Maker	Not published	Not published
Website	hartigansoftware.co.uk	warp.co
On payroll tax software	#22 of 31	#26 of 31

Hartigan RTI Pro: what it does well

Imports HMRC XML and Excel data
Validates records before filing
Direct Government Gateway connection
Supports several RTI submission types
NEST setup and submission guidance

What to know first

Windows only
No free plan
Does not calculate payroll
Prices exclude VAT

Warp Tax Compliance: what it does well

Automates registrations, filings, and notice resolution
Monitors over 10,000 jurisdictions
Handles federal, state, and local payroll taxes
Integrates with major accounting and HR tools
REST API, CLI, and MCP access

What to know first

No free plan
Starter covers only up to three states
Platform fees are added to plan prices

Alternatives to Hartigan RTI Pro Alternatives to Warp Tax Compliance The whole list