990.tax Nonprofit Lookup
Check whether a US charity is still tax-exempt and see its IRS Form 990 financials and officers.
Searches IRS records for US nonprofits by name, EIN or state. Shows exempt status, revocations, 501(c) type, deductibility, filing history, and up to five years of e-filed financials and officer pay. Also finds which Form 990 a group must file, its due dates, and explains IRS e-file reject codes. Read-only public data, no sign-in required.
Try asking Muse: "Check whether the charity I plan to donate to is still tax-exempt and show me its latest financial summary."
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Source: Found in the official MCP Registry (tax.990/nonprofit-lookup) · First listed November 3, 2026
Last 24 hours
Each bar is one check, every 15 minutes. Green means it answered. Last checked 49 min ago.
Is it safe to connect?
What Muse can see: It does not ask you to sign in, so it cannot see your accounts. It only sees what Muse sends it from your request.
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How to add it to Muse
Not in Muse's Connectors list yet, but Muse can still use it. Copy the request below and paste it into Muse. Muse asks before it shares anything with the app's site. Meta does not review apps used this way, so only use ones you trust. We tested this in the Muse app on September 24, 2026: Muse used an app's link directly this way and returned a live answer.
https://990.tax/mcpNot in Muse's Connectors list yet. Muse can still use it: its page gives you a request to paste into Muse.
Also use it in ChatGPT or Claude
990.tax Nonprofit Lookup is a remote MCP server, so any assistant that can add a custom connector by link can use it. Same link, same tools.
Add it to ChatGPT
- 1
Open ChatGPT settings
In ChatGPT, open Settings, then Connectors (called Apps & Connectors on some accounts).
- 2
Turn on developer mode
Under Advanced settings, switch on Developer mode. That is what lets you add a connector by link.
- 3
Create the connector
Choose Create, give it a name, paste the link as the MCP server URL, and save. If it needs a sign-in, ChatGPT asks for it here.
- 4
Use it in a chat
Start a chat, open the tools menu, pick the connector, and ask. ChatGPT asks before it runs a tool the first time.
Custom connectors need a paid ChatGPT plan, and on Team, Enterprise and Edu accounts only an admin can add them. Our "Working" label means the server answered us; it cannot tell whether your plan lets you add it. All connectors that work in ChatGPT
Add it to Claude
- 1
Open Claude settings
In Claude, open Settings, then Connectors.
- 2
Add a custom connector
Choose Add custom connector, give it a name, and paste the link.
- 3
Connect and use it
If it needs a sign-in, Claude sends you to it. Then turn the connector on in a chat from the tools menu and ask.
Custom connectors are available on paid Claude plans; on Team and Enterprise accounts an admin may need to add them. Our "Working" label means the server answered us; it cannot tell whether your plan lets you add it. All connectors that work in Claude
https://990.tax/mcpWhat people ask Muse to do
Technical details: safety screening, tools, response time and recent checks
Response time at the last check: 580ms. Worked in n/a of checks over 30 days.
Screening · November 3, 2026
Screened, no issues found
Screening looks for known threats and hidden instructions at the time of the check, and runs again weekly and whenever the tool list changes. It cannot see the server's code, so only connect what you need and review what Muse asks to do. How screening works.
Tools · 8
search_nonprofitsFind US tax-exempt organizations by name or EIN in IRS records. Returns up to 10 matches with EIN, city, state, exempt status (active, revoked, reinstated, terminated) and the latest form filed. Use the EIN with the other tools.get_nonprofit_profileOne organization's IRS record: exempt status, 501(c) subsection, NTEE category, ruling year, deductibility (Publication 78), fiscal year end, which return it files, last filing, and the latest e-filed financial summary. Optional sections: financials (up to 5 years of revenue, expcheck_exempt_statusWhether the IRS automatically revoked an organization's tax exemption (revocation, posting and reinstatement dates), and which of its last three ended accounting years have no return on the IRS public files. Three consecutive missing years revoke the exemption (IRC 6033(j)).which_990_formWhich annual return applies under the IRS thresholds: 990-N (gross receipts normally $50,000 or less), 990-EZ (under $200,000 and assets under $500,000), 990, 990-PF, or none (churches, group-return members). With an EIN, missing amounts come from the IRS Business Master File. Ciget_filing_due_dateDue date of a Form 990-N, 990-EZ, 990 or 990-PF for a fiscal year end and tax year, moved off weekends and legal holidays, the Form 8868 extended due date (none for the 990-N), days remaining, and late-filing consequences. Give the fiscal year end month or an EIN. Tax year = the get_nonprofit_statsCounts and totals for US tax-exempt organizations from IRS public data: national, one state, or one NTEE major category (A-Z). Active organizations, 990-N filers, revocations, and revenue, assets, employees and pay from e-filed returns; national adds e-Postcard filers by year, reget_top_nonprofitsRanked lists from e-filed Form 990 returns, national (25) or per state (10): highest-paid executives, largest by revenue, most money raised, richest by net assets, biggest employers.explain_irs_reject_codePlain-English meaning of an IRS Modernized e-File business rule reject code for Forms 990-N, 990-EZ, 990 and 8868 (e.g. R0000-922-01), the IRS rule text, and how to fix it.Link
https://990.tax/mcpQuestions about 990.tax Nonprofit Lookup in Muse
How do I connect 990.tax Nonprofit Lookup to Muse?
Not in Muse's Connectors list yet, but Muse can still use it. Paste this into Muse: "Use 990.tax Nonprofit Lookup to help me. It is a free service with an MCP server at https://990.tax/mcp. It does not need an API key. Ask me before you share anything with it." Muse asks before it shares anything with the app's site. Meta does not review apps used this way, so only use ones you trust. We tested this in the Muse app on September 24, 2026: Muse used an app's link directly this way and returned a live answer.
Is 990.tax Nonprofit Lookup working right now?
At the last check (November 3, 2026, 18:21 UTC) the endpoint was working, answering in 580ms. It is checked every 15 minutes.
Is 990.tax Nonprofit Lookup safe to connect to Muse?
It was screened on November 3, 2026 with the result "screened, no issues found". Screening checks the domain against threat feeds and reads the tools for hidden instructions and requests for passwords or card numbers. It cannot see the server's code, so grant only the access you need.
What can 990.tax Nonprofit Lookup do in Muse?
It exposes 8 tools, including search_nonprofits, get_nonprofit_profile, check_exempt_status, which_990_form. For example, you could ask Muse: "Check whether the charity I plan to donate to is still tax-exempt and show me its latest financial summary."
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