API & MCP

Grant data for AI agents and apps.

Semantic grant search, funder profiles, and award history over a corpus of 5,000+ verified-open opportunities — not an inflated catalog of duplicates and expired listings. A REST API plus a Model Context Protocol server for Claude, Cursor, and any MCP client.

Add to Claude or Cursor See pricing

Five lines, then your AI can find grants

Add the MCP server to your client config and restart. Your assistant can now search the open-grant corpus, pull funder profiles, and check eligibility — in the flow of a normal conversation. The free tier needs no key.

Works with Claude Desktop, Cursor, and any MCP client
Streamable HTTP — no local install
Read-only and idempotent: safe for autonomous agents

mcp.json

{
  "mcpServers": {
    "grantsonar": {
      "url": "https://grantsonar.com/api/mcp"
    }
  }
}

Higher limits? Add "headers": { "Authorization": "Bearer gsk_…" } with a key from Settings → API & MCP.

Add it to your client

The free tier needs no key. For higher limits, add an Authorization: Bearer header with a key from Settings → API & MCP.

Claude Code (CLI)

One command in your terminal

claude mcp add --transport http grantsonar https://grantsonar.com/api/mcp

Claude Desktop

Settings → Connectors → Add custom connector, then paste the URL

https://grantsonar.com/api/mcp

Cursor

~/.cursor/mcp.json

{
  "mcpServers": {
    "grantsonar": { "url": "https://grantsonar.com/api/mcp" }
  }
}

Windsurf

~/.codeium/windsurf/mcp_config.json

{
  "mcpServers": {
    "grantsonar": { "serverUrl": "https://grantsonar.com/api/mcp" }
  }
}

Codex CLI

~/.codex/config.toml

[mcp_servers.grantsonar]
url = "https://grantsonar.com/api/mcp"

The tools

Read-only tools your agent can call directly. More of the graph is rolling out.

search_grantsLive

Semantic + keyword search over the catchable grant corpus. Filter by state, source, funder, eligibility. Returns deadlines, award amounts, and a GrantSonar link.

get_grantLive

Full detail for one opportunity by id — synopsis, eligibility, deadlines, award floor/ceiling, application URL.

search_funders / get_funderSoon

230K+ foundation profiles — giving focus, recent grants, financials, and leadership. The funder side of the graph.

get_past_winnersSoon

Federal award history — who actually won, how much, and where. Competitive intelligence on every program.

match_grants_to_orgSoon

Score and rank opportunities against an organization profile (mission, focus, geography, eligibility). Our matching engine, not just keyword search — most grant APIs do not have this.

Why build on GrantSonar

Honest, verified-open data

We return 5,000+ grants that are actually open right now — not an inflated catalog of duplicates and expired listings. Eligibility-aware and freshness-checked against the source.

Matching, not just search

match_grants_to_org scores opportunities against a real org profile. Hand your agent a mission and get ranked, eligible results — the thing keyword APIs can’t do.

Read-only and fast

Every tool is read-only and idempotent. No write access, no surprises — safe to hand to an autonomous agent. Semantic search returns in tens of milliseconds.

Simple, metered pricing

Start free, no signup. Pay only when you scale — and the per-call rate drops as you grow.

Free

$0no signup

200 calls / day

For evaluation and AI-assistant use. Anti-abuse daily cap, shared fair-use.

Add to Claude

Hobby

$29/mo

10K calls / mo

$2.90 / 1K

Your own key + burst capacity for side projects and batch pulls.

Start checkout

Best value

Developer

$99/mo

40K calls / mo

$2.48 / 1K

Production apps. 60% more volume than the next platform at a third less.

Start checkout

Growth

$339/mo

150K calls / mo

$2.26 / 1K

Scaled usage with the best per-call rate. Priority support.

Start checkout

Enterprise

Custom

Unlimited

Volume pricing

Bulk exports, custom datasets, SLA. Still far below legacy data vendors.

The free tier is live now, no signup. Paid plans use hard monthly caps today; the $/1K figures are effective-rate comparisons, not metered overage charges. Every tier undercuts other grant APIs on price and volume, and runs far below opaque enterprise data vendors. Metered overages and AI-heavy operations, if added, are future options.

Developer FAQ

Do I need a GrantSonar account to use the MCP?

No. The free tier is unauthenticated — drop the endpoint into your MCP client and start searching. Create a free account and generate a key only when you want higher limits.

What is the data, exactly?

Federal, state, and foundation grant opportunities that are currently open, plus 230K+ funder profiles and federal award history. We verify open status against the source rather than padding the count with closed listings.

How do rate limits work?

Free is a per-day cap for evaluation. Paid plans are monthly query quotas with burst capacity. AI-heavy operations (if added later) are metered separately so a runaway agent can’t blow through your plan.

Can my agent write or change anything?

No. Every tool is read-only and idempotent. It is safe to expose to an autonomous agent — the worst it can do is search.

How does this compare to legacy nonprofit-data APIs?

Self-serve, transparent pricing, and a verified-open corpus — at a fraction of the cost of opaque enterprise data vendors, and undercutting other grant APIs on both price and volume.

Point your agent at the real open-grant graph.

Free to start, no signup. Five lines of config and your assistant can find grants that are actually open.

Get started