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

Seamless.AI is a credit-metered sales platform with a large claimed dataset and no public price. ContactOut is a LinkedIn-first finder with public seat prices and an API you get through a meeting. Pick by who will use it: reps, recruiters or code.

Verdict

• Pick Seamless.AI if reps want prospecting, mobile numbers and outreach in one app, and you are happy to buy through sales. It claims the bigger dataset, and one credit covers a contact's email and phone together.
• Pick ContactOut if recruiters or reps work from LinkedIn in a browser and want a price they can read. Email is $49 a month on monthly billing, and Email + Phone is $99.
• Pick neither if you pull data in code or through an agent at volume. Both hide the API price behind a quote or a meeting, so LeadOcean is the third option: Free, then Pro at $499 a month flat.

Side by side

Every figure below is a vendor claim from the linked page, checked September 2026.

Data and coverage

Seamless.AI claims the larger dataset on every line: 2.2B+ contacts, 1.6B+ business emails and 448M+ mobile numbers. ContactOut claims 800M profiles, 200M work emails and 100M direct dials. Both are the vendors' own numbers, and neither is audited.

ContactOut's own pages disagree (ContactOut data page, September 2026). The homepage headline says 350M professionals, the data page says 800M, and the MCP page says 600M+. Ask which number your plan reaches.

ContactOut is stronger on personal email, which it counts separately at 150M. Seamless.AI does not break out personal email on the pages we checked. It leads on mobile numbers.

Seamless.AI search is wider on the API side. Contact search takes 39 filter and modifier parameters and company search takes 23 (Seamless.AI docs, September 2026). ContactOut lists 20+ searchable fields on its homepage.

Email quality is claimed on both sides and proven on neither. Seamless.AI says it verifies emails and credits back invalid ones (Seamless.AI, September 2026). ContactOut says its data is triple-verified with 99% confidence, and sells verifier endpoints separately.

Run the same 100 names through both before you trust any headline number. Match rate on your own list is the only figure that counts.

API and developer experience

Both have a REST API and a hosted MCP server. They differ in how you get a key and how a lookup returns.

Seamless.AI is asynchronous. You search, then submit a research job, then poll for the result or take a webhook. The key comes from account settings, and API access must be enabled on the account (Seamless.AI docs, September 2026).

  # step 1, search. Costs 1 credit per 10 results returned.
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":["Chief Technology Officer"],"companyName":["Acme"]}'

  # step 2, research. Costs 1 credit per contact. Returns request IDs to poll.
curl -X POST "https://api.seamless.ai/api/client/v2/contacts/research" \
  -H "Token: $SEAMLESS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"searchResultIds":["searchResultId1","searchResultId2"]}'

ContactOut returns in one call, but you must ask for contact details. By default the enrich endpoint returns the profile without emails or phones, so you pass an include list (ContactOut API docs, September 2026). A found email costs one email credit and a found phone costs one phone credit.

curl -X POST "https://api.contactout.com/v1/people/enrich" \
  --header "Content-Type: application/json" \
  --header "token: $CONTACTOUT_API_TOKEN" \
  --data '{"linkedin_url":"https://linkedin.com/in/jane-doe","include":["work_email","phone"]}'

On limits, ContactOut is the faster of the two for plain lookups: 1,000 requests a minute on most endpoints against 60 on every Seamless.AI endpoint. On People Search both sit at 60 a minute. Seamless.AI moves more per call, with up to 500 records in a research request.

Pricing

Seamless.AI publishes no dollar price. Its pricing page is a quote form, and the API page says keys are bundled with plans or sold as an add-on (Seamless.AI pricing, September 2026). Licenses carry credits: Basic 250 a month, Pro 10,000 a month, Free 50 once (credit docs, September 2026).

Contracts are annual, sales are final, and cancelling needs 60 days' notice before renewal or it renews for 12 months (Seamless.AI terms, September 2026).

ContactOut publishes seat prices. Email is $49 a month on monthly billing or $39 billed yearly, with unlimited emails and 300 exports a month. Email + Phone is $99 monthly or $79 yearly, with 600 exports (ContactOut pricing, September 2026). Every self-serve plan is one user per company.

"Unlimited" has a ceiling. Fair use is 2,000 email credits and 1,000 phone credits per account per month (ContactOut terms, September 2026). The API plan shows Contact Us with no price.

Hidden costs

• Seamless.AI misses. The docs mark a record with no result as missing when you poll, but do not say whether it is charged (Seamless.AI docs, September 2026).
• Seamless.AI refills. Credits refresh monthly on the contract date, and the docs state no rollover of unused credits. Bulk pool credits do not replenish.
• ContactOut credits. The API charges per email or phone found, with no dollar price per credit published.
• ContactOut terms. Refund, renewal and credit expiry sit in a Subscription Agreement that is not public (ContactOut terms, September 2026).
• ContactOut seats. Self-serve plans are one user per company, so a team cannot split a plan.

Worked example: 10,000 records a month

The Seamless.AI line is 10,000 researches at 1 credit each, plus 10,000 / 10 = 1,000 credits of search (credit docs, September 2026). That fits one Pro license at 10,000 credits for researches alone, and two once search is counted. The ContactOut line ignores the 300 exports a month the plan also lists, and the one-user rule means a real 10,000-a-month buyer needs the quote-only API plan.

Worked example: 1M records a month

Seamless.AI at 1M is 1,000,000 / 10,000 = 100 Pro licenses, or a bulk credit pool, and both are quote only. The price per credit is not published. At 60 requests a minute and 500 records a call, 1M records is 2,000 search calls and 2,000 research calls. That is about 34 minutes of request windows each, plus polling (Seamless.AI docs, September 2026).

ContactOut at 1M is 500 account-months at the fair-use ceiling. Self-serve allows one user per company, so adding accounts is not a public path (ContactOut terms, September 2026). Volume means the API plan, which is quote only. We do not multiply a seat price out to 1M.

Where Seamless.AI wins

• Bigger claimed dataset. 2.2B+ contacts and 448M+ mobile numbers against ContactOut's 800M profiles and 100M direct dials.
• One credit for email and phone. A single credit covers a contact's email and phone together, so a mobile number costs nothing extra.
• A fuller sales app. It ships a Chrome extension, a dialer, emailing and buyer intent (Seamless.AI, September 2026).
• A larger MCP surface. 57 tools across 13 domains against ContactOut's 15.

Where ContactOut wins

• A price you can read. Plans start at $49 a month and the free tier gives 5 emails, 5 phones and 5 exports a day. Seamless.AI sends you to a quote form.
• Personal email. 150M personal emails, counted on their own line, which recruiters often need.
• Faster plain lookups. 1,000 requests a minute on most endpoints against 60.
• Lighter commitment. Monthly billing is listed. Seamless.AI contracts are annual with a 60-day notice window.
• LinkedIn workflow. The extension and its free daily allowance suit one-off lookups by recruiters.

If you need volume through an API

If neither price fits a pipeline, LeadOcean is a data API with a hosted MCP server and two plans. Free is 1,000 records, one-off, no card, with the same API and MCP server as Pro. Pro is $499 a month flat, with no credits and no per-record price.

It has 693M people and 63M companies over REST and MCP, with a limit of 100 requests per second per key. Export up to 50,000 rows per request with POST /v1/exports. It has no Chrome extension, dialer or sequencer, so reps who live in a browser should stay with the tools above (LeadOcean exports docs, September 2026).

FAQ