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

Lusha and Seamless.AI both sell B2B contact data on credits, but they sell it differently. Lusha prints its prices and gives every plan an API key. Seamless.AI claims a database about four times larger, adds a dialer and emailing, and sells by quote.

Verdict

• Pick Lusha if you want to read the price before you talk to anyone, start on a free plan and pay month to month. It publishes its plans, its credit costs and its per-key API limits, and it has a Chrome extension.
• Pick Seamless.AI if reps prospect, call and email from one app, you want the largest claimed pool of mobile numbers, and you accept a quote and an annual contract.
• Pick neither if you need volume through an API at a price you can read. Lusha has no public price at 1M records, and Seamless.AI has no public dollar price at all. LeadOcean is one option: Pro is $499 a month, flat, with no credits.

Side by side

Data and coverage

Seamless.AI claims the bigger database by a wide margin. It states 2.2B+ verified contacts and 121M+ companies, against Lusha's 525M+ contacts and 29M+ companies (Seamless.AI API page, September 2026; Lusha homepage, September 2026). All of these are the vendors' own numbers, and neither publishes how it counts a contact.

Phones show the same gap. Seamless.AI claims 448M+ verified mobile numbers, about 20% of its contact count. Lusha claims 117M+ direct dials, about 22% of its own. So the share is similar, and the pool is not.

Emails are harder to compare. Lusha says 165M+ emails, about 31% of its contacts. Seamless.AI says 1.6B+ verified business emails on its homepage (Seamless.AI homepage, September 2026). That is a count of addresses, and Lusha's may count people, so do not read the ratio as a fact.

Depth differs too. Lusha says 78 fields per record and 26 buying signals refreshed weekly. Seamless.AI says 100+ data points per profile, plus buyer intent and job-change tracking (Lusha homepage, September 2026; Seamless.AI homepage, September 2026).

Size is not accuracy. Both vendors claim verified data, and neither claim can be audited from outside. Run the same 50 people through both and compare match rate and bounce rate.

API and developer experience

Both have a REST API and an official MCP server. Lusha gives every user an API key on every plan, Free included. Its pricing page lists API as a named feature from Pro and API Advanced on Premium, so check the plan you are buying (Lusha pricing, September 2026).

Seamless.AI ties API access to the license. It publishes no standalone API price, and says usage draws credits (Seamless.AI API page, September 2026).

Lusha's V3 API takes the key in an api_key header. Search finds contacts by name and domain, LinkedIn URL or email. Revealing the email or phone is a second call to enrich, and that step spends credits (Lusha API overview, September 2026). V2 stays live until November 18, 2026.

curl --request POST \
  --url https://api.lusha.com/v3/contacts/search \
  --header "api_key: $LUSHA_API_KEY" \
  --header "Content-Type: application/json" \
  --data '{
    "contacts": [
      { "clientReferenceId": "my-ref-1", "firstName": "Jane", "lastName": "Doe", "companyDomain": "acme.com" }
    ],
    "options": { "includePartialProfiles": true }
  }'

Lusha's docs disagree on a miss. The API guide says a request costs at least 1 credit even with no data (Lusha API guide, September 2026). The V3 billing FAQ says no credit is deducted for a no-match request (Lusha billing FAQ, September 2026).

Seamless.AI uses a three-step flow: search, research, then poll. The Token header carries the key. Search returns a searchResultId for each match (Seamless.AI first-request guide, September 2026).

curl -X POST https://api.seamless.ai/api/client/v1/search/contacts \
  -H "Content-Type: application/json" \
  -H "Token: $SEAMLESS_API_KEY" \
  -d '{
    "jobTitle": ["Chief Technology Officer"],
    "companyName": ["Acme Corp"],
    "limit": 5
  }'

You then send those IDs to POST /contacts/research, which returns a requestId per record. Results come back by polling GET /contacts/research/poll, or by webhook. The docs suggest a 2 to 5 second gap between polls. Research is asynchronous, so one lookup is never a single round trip (Seamless.AI rate limits, September 2026).

Its docs do not say whether a research request that finds nothing is charged, so ask before you budget for misses.

Rate limits favor Seamless.AI at the low end and Lusha's top plans at the high end. Seamless.AI allows 60 requests a minute per endpoint, shared across the organization, with separate windows for search, research and poll. Lusha sets limits per key by plan. Free and Starter get 100 requests a day, Pro gets 1,500 a day, and Premium gets 300 a minute and 18,000 a day. Lusha's V3 page also sets a ceiling of 25 requests a second per account (Lusha rate limits, September 2026).

On MCP, Lusha has 50 tools and Seamless.AI has 57. Lusha's server shares the REST credit pool. Seamless.AI says its search tools use no credits and its research tools do, and an admin must switch MCP on first.

Pricing

Lusha prints its prices. Seamless.AI does not. That decides which one you can budget before a sales call.

Lusha's public plans, in USD (Lusha pricing, September 2026):

An email costs 1 credit, a phone number 5 and company info 1. A bulk request adds 1 credit per 25 results, up to 100 per request (Lusha API guide, September 2026; Lusha credits, September 2026). Scale is custom, with no published rate.

Seamless.AI publishes no dollar price. Its pricing page is a quote form (Seamless.AI pricing, September 2026). It does publish credits. A Free license has 50 with no refill, Basic has 250 a month and Pro has 10,000 a month per license (Seamless.AI credit docs, September 2026). Research costs 1 credit per record, and one credit covers the email and the phone together. Search costs 1 credit per 10 results returned (Seamless.AI rate limits, September 2026).

The contract differs as well. Seamless.AI subscriptions are annual, with monthly or annual billing. Sales are final, and cancelling needs 60 days' notice before renewal or it renews for 12 months (Seamless.AI terms, September 2026). Lusha sells monthly plans, and yearly billing is 25% off.

10,000 records a month

• Lusha, work emails by bulk API: 10,000 email credits + 10,000 / 25 = 400 request credits = 10,400 credits. The largest monthly step on Premium is 10,000 credits for $977.40. The other 400 credits have no published price.
• Lusha, email and phone: 10,000 x (1 + 5) + 400 = 60,400 credits. That is about six times the largest monthly step.
• Seamless.AI: 10,000 credits, which is one Pro license for a month. If each record first comes from a search, add 10,000 / 10 = 1,000 credits, so 11,000. No dollar price is published.

1M records a month

• Lusha: No public 1M price. 1,000,000 work emails by bulk API need 1,000,000 + 1,000,000 / 25 = 1,040,000 credits. The top public step is 10,000 credits a month, so that is 104 times larger. Scale is a custom quote.
• Seamless.AI: No public 1M price. 1,000,000 researches are 1,000,000 credits, or 1,100,000 with a search first. At 10,000 credits per Pro license, that is 100 licenses, or a bulk credit pool bought by quote.

On throughput, Seamless.AI at 500 records a call and 60 calls a minute needs 2,000 search calls and 2,000 research calls, about 34 minutes each. That counts request windows only, because the docs give no time for async completion. Lusha at 100 per request needs 10,000 calls, about 5.6 hours at Premium's 1,800 an hour.

Get a written quote from each at your volume. Ask both what a miss costs, and whether API and MCP calls draw on the same pool as the app.

Where Lusha wins

• A price you can read. You can size a 10,000-record month from a public page, and there is a free plan with 40 credits a month.
• Month-to-month billing. Monthly plans, with 25% off for paying yearly, and no 60-day notice window.
• An API key on every plan. The Free plan included, with a 50-tool MCP server on the same credit pool.
• Published API limits. Per-key limits by plan, so you can plan a job before you buy.
• A smaller, lighter tool. A Chrome extension and CRM apps, with no dialer or emailing suite to buy (Lusha homepage, September 2026).

Where Seamless.AI wins

• A bigger claimed database. 2.2B+ contacts and 448M+ mobile numbers, against Lusha's 525M+ and 117M+. If you need mobile numbers at scale, it claims more of them.
• A full sales app. A Chrome extension, a dialer, emailing, buyer intent and job-change tracking in one place (Seamless.AI homepage, September 2026).
• One credit for email and phone. Researching a contact costs 1 credit and returns both. On Lusha, a phone costs 5 credits.
• Larger batches. Up to 500 records per research request, against 100 per request on Lusha.
• More keys. Up to 25 persistent API keys and 25 OAuth connections per organization.

If you need volume through an API

Neither tool prints a price at 1M records, and both bill by credit. LeadOcean is a data API and MCP server with a flat price. The Free plan gives 1,000 records, one-off, with no card, and Pro is $499 a month with no credits and no per-record price.

It is REST and MCP on every plan, with 100 requests per second per key. POST /v1/exports returns up to 50,000 rows per request, so a 1M-row pull is 20 calls over two days (LeadOcean exports docs, September 2026). Past the fair-usage line a very large month is paced down, not cut off.

LeadOcean holds 693M people and 63M companies. That is a smaller database than Seamless.AI claims. It has no Chrome extension, dialer or sequencer, so it is a data source for code and agents, not a rep tool. Compare plans on the pricing page, or read the Lusha alternatives and LeadOcean as a Lusha alternative.

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