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Sidr Tax
by Sidr Tax
What Sidr Tax is
Sidr Tax is an API-based sales tax service from Sidr Tax, headquartered in Dover, Delaware. It supports sales tax registration and automated return filing, but the listed service does not provide sales tax calculation on its own. The free plan has no monthly subscription fee and includes nexus monitoring across all states, detailed reporting and analytics, CSV transaction imports, historical liabilities analysis, comprehensive risk assessment, and address validation. The Plus plan is listed at $60 a month, with billing described as 60 USD per filing and 150 USD per state registration. Plus adds automated filing and remittance, registration and deregistration, a virtual mailbox for state notices, rooftop-accurate calculations, automatic tax-code classification, and enhanced filing autopilot. Premium has no listed price and adds advanced API access, dedicated account management, expert access, volume discounts, Voluntary Disclosure Agreements, and error insurance coverage.
Who it suits
It suits businesses needing nexus monitoring, state registration, and automated sales tax return filing through an API. The free tier fits monitoring and analysis, while paid plans add filing and registration services.
What it does well
- Free nexus monitoring across all states
- Automated sales tax return filing
- Registration and deregistration support
- CSV imports and liability analysis
- API access is available
What to know first
- Does not provide sales tax calculation
- Plus billing includes per-filing charges
- Only sales tax is supported
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Free | Zero monthly subscription fees; free nexus monitoring · Nexus monitoring across all states · Detailed reporting and analytics · CSV transaction imports · Historical liabilities analysis · Comprehensive risk assessment · Address validation | Free |
| Plus | $60 per filing; $150 per state registration · Automated filing and remittance · Registration and deregistration · Virtual mailbox for state notices · Rooftop-accurate tax calculations · Automatic tax code classification · Enhanced filing autopilot | $60 a month |
| Premium | Advanced API access · Dedicated account management · Priority access to sales tax experts · Volume-based discount · Voluntary Disclosure Agreements · Error insurance coverage | On request |
As sidr.io lists them, read 22 Sept 2026. The maker's own page has the final word.
Verdict
Sidr Tax covers monitoring, registration, and filing, with a free analysis tier and paid automation. Confirm the Plus billing details and whether its API scope matches your tax workflow.
Facts from Sidr Tax's own pages
- API access
- Yes · sidr.io, 22 Sept 2026
- Filing support level
- automated · sidr.io, 22 Sept 2026
- Free plan
- Yes · sidr.io, 22 Sept 2026
- Headquarters
- Dover, Delaware, United States · sidr.io, 28 Sept 2026
- Return filing
- Yes · sidr.io, 22 Sept 2026
- Sales tax calculation
- No · sidr.io, 22 Sept 2026
- Supported tax types
- sales tax · sidr.io, 22 Sept 2026
- Tax registration
- Yes · sidr.io, 22 Sept 2026
Where Sidr Tax stands on Freedom251
- Tax Compliance Software#19 of 105