Seamless.AI vs LeadIQ (2026): Data, Pricing and API Compared

Seamless.AI and LeadIQ both sell contact data on credits, and neither prints a price you can multiply out to 1M records. Seamless.AI claims the bigger database and documents its API limits. LeadIQ has the readable small-volume price and the Chrome extension.

Verdict

• Pick Seamless.AI if you want the larger claimed database, a documented API with 500-record batches and a 57-tool MCP server, and you can work through a sales quote (Seamless.AI API page and MCP docs, September 2026).
• Pick LeadIQ if reps prospect from LinkedIn, track job changes and push to Salesforce, and you want a price you can read for a few thousand credits a month (LeadIQ pricing, October 2026).
• Pick neither if you need volume through an API at a price you can read. Both have no public 1M price. LeadOcean is one option: Pro is $499 a month, flat.

Side by side

Data and coverage

Seamless.AI claims the larger database by a wide margin. It says 2.2B+ verified contacts, 1.6B+ verified business emails, 448M+ verified mobile numbers and 121M+ companies (Seamless.AI API page and homepage, September 2026). LeadIQ says 750M+ professional profiles, refreshed every month, with up to 200M re-verified as people change jobs (LeadIQ pricing FAQ, October 2026).

Every one of those is a vendor claim. Neither says how a "contact" is counted or how many rows are stale. A bigger number is not a better hit rate.

On phones, the two print different measures. Seamless.AI gives a count of verified mobiles. LeadIQ gives an 85% global match rate, 70% in EMEA, and over 90% accuracy on verified numbers. A count and a match rate cannot be compared.

LeadIQ prints no email count. It does bill only for data it returns: an email that fails verification is not returned and costs nothing (LeadIQ developer docs, October 2026). Seamless.AI's docs do not say whether a research request that finds nothing is charged.

Filters differ in depth. Seamless.AI contact search takes 39 filter parameters and company search 23 (Seamless.AI docs, September 2026). LeadIQ has 12 people filter fields and 13 company filter fields (LeadIQ developer docs, October 2026).

Run the same 100 people through both before you sign anything.

API and developer experience

Both have a hosted MCP server and an API, built differently. Seamless.AI is REST in three steps: search, research, poll. LeadIQ is one GraphQL endpoint with search and enrichment as queries.

Seamless.AI: search contacts, then research the results by searchResultId. The API key goes in a Token header. The reference lists a v2 base URL, https://api.seamless.ai/api/client/v2 (Seamless.AI docs, October 2026). The requests below use placeholders.

curl -X POST "https://api.seamless.ai/api/client/v2/search/contacts" \
  -H "Token: $SEAMLESS_API_KEY" \
  -H "content-type: application/json" \
  -d '{"limit":50,"jobTitle":["VP Sales"],"contactCountry":["United States"]}'

curl -X POST "https://api.seamless.ai/api/client/v2/contacts/research" \
  -H "Token: $SEAMLESS_API_KEY" \
  -H "content-type: application/json" \
  -d '{"contacts":[{"contactName":"Jane Doe","companyName":"Acme"}]}'

Research returns request IDs with a 202. You then poll GET /contacts/research/poll with requestIds, or use a webhook (Seamless.AI docs, October 2026). Plan for an async loop, not a single call.

LeadIQ: one POST to https://api.leadiq.com/graphql. Its docs show this paged people search.

query {
  flatAdvancedSearch(input: {
    companyFilter: {
      locations: [
        { country: "United States", areaLevel1: "California" }
      ]
    }
    limit: 50
  }) {
    totalPeople
    people { id name title }
    after { key value }
  }
}

Offset paging stops at 10,000 results. Past that you pass the after cursor back unchanged (LeadIQ developer docs, October 2026).

Rate limits are the clearest gap. Seamless.AI allows 60 requests a minute per endpoint, shared by every key in the organization, with separate windows for search, research and poll (Seamless.AI docs, September 2026). LeadIQ does not publish one in its developer docs, so ask for it before you plan a bulk job.

On MCP, the credit rules differ. Seamless.AI's search tools use no credits and its research tools do, across 57 tools in 13 domains. LeadIQ's 23 tools include list management and Salesforce export, and bill per data point on their own rates, separate from the GraphQL ratesheet. Its developer docs say a free account can connect, but its MCP page says a paid subscription is needed. Confirm with LeadIQ before you plan around a free connection (LeadIQ developer docs and MCP page, October 2026).

Pricing

Neither tool prints a price at volume, so the examples below count credits and, where a price exists, show it. Seamless.AI publishes no dollar price for any license (Seamless.AI pricing, September 2026). LeadIQ publishes a slider up to 6,750 credits a month, then says Enterprise. Monthly list price comes first, then the billed-yearly figure.

At 10,000 records a month

Take 10,000 people with a work email.

• Seamless.AI: 10,000 contact researches is 10,000 credits. A Pro license carries 10,000 credits a month, so one license covers it only if you skip search (Seamless.AI credit docs, September 2026). Search first at 1 credit per 10 results and you add 1,000 credits, 11,000 in all. No dollar price is published for a license.
• LeadIQ: at the MCP rate, 10,000 emails x 1 credit = 10,000 credits, which is above the slider. The largest step is 81,000 credits a year (6,750 a month), and annual billing is 25% off (LeadIQ pricing, October 2026). So there is no public price at 10,000.

LeadIQ's top step buys 6,750 work emails a month. With a phone too, a person is 11 credits over MCP, so 6,750 / 11 = 613 people. Seamless.AI has no rate to compare, because one credit covers a contact's email and phone together (Seamless.AI docs, September 2026).

At 1M records a month

• Seamless.AI: no public 1M price. 1,000,000 researches is 1,000,000 credits, or 1,100,000 with search first. At 10,000 credits per Pro license that is 100 licenses, or a bulk pool, and both are quote only (Seamless.AI docs, September 2026).
• LeadIQ: no public 1M price. At MCP rates, emails alone are 1,000,000 credits and email plus phone is 11,000,000, against a slider that stops at 6,750 a month. Enterprise is a quote (LeadIQ pricing, October 2026). We do not multiply the slider rate out to 1M and call it a price.

Seamless.AI's throughput is knowable. At 500 records a call and 60 requests a minute, 1M records is 2,000 search calls and 2,000 research calls. Each set takes about 34 minutes, in separate windows, plus polling (Seamless.AI docs, September 2026). Async completion time is not documented. LeadIQ's throughput is unknown without its rate limit.

Contract terms matter at that scale. Seamless.AI subscriptions are annual, sales are final, and cancelling needs 60 days' notice before renewal or it renews for 12 months (Seamless.AI terms of use, September 2026). Ask both vendors for a written quote at your volume.

Where Seamless.AI wins

• A much larger claimed database. 2.2B+ contacts and 121M+ companies against 750M+ profiles and no company count.
• A documented API contract. The limits, batch sizes, credit rules and poll flow are in the docs.
• One credit for email and phone. A contact researched is one credit, where LeadIQ charges 11 for both over MCP.
• A bigger MCP server. 57 tools against 23, with free search tools.
• More search filters. 39 on contacts and 23 on companies, against 12 and 13.

Where LeadIQ wins

• A price you can read at small volume. Pro starts at $20 a month for 200 credits, with up to 5 users, and Free costs nothing (LeadIQ pricing, October 2026).
• The LinkedIn workflow. A Chrome extension, job-change tracking and CRM sync, aimed at reps who prospect one person at a time.
• Billing on what comes back. Failed email verifications are not returned and cost nothing.
• Salesforce export from MCP. Its connector saves to lists and exports to Salesforce.
• Deep paging. Cursor paging reads result sets past 10,000.
• A short contract path. Plans go through a slider, with no quote needed up to 6,750 credits a month.

If you need volume through an API

We build LeadOcean, so weigh this section accordingly. LeadOcean holds 693M people and 63M companies, reachable over REST and an MCP server with 12 tools. Free is 1,000 records, one-off, with no card. Pro is $499 a month, flat, with no credits, no per-record price and no overage invoice (LeadOcean pricing, September 2026).

For bulk work, POST /v1/exports returns up to 50,000 rows per request. The app has an Exports page with a filter builder, a column picker, a price preview and CSV download (LeadOcean exports docs, September 2026). There is no sequencer, dialer or Chrome extension. If your reps live in Seamless.AI or LeadIQ, keep it for that.

FAQ