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

Seamless.AI is the bigger claimed database and a full rep workspace, so it fits sales teams that live in one app. Prospeo is the cheaper, clearer way to buy verified emails and mobiles by credit. Only Prospeo publishes a price you can multiply, and neither tool has a simple 1M plan.

Verdict

• Pick Seamless.AI if reps will prospect, call and email from one platform, and you want one credit to cover a contact's email and phone together (Seamless.AI API docs, September 2026).
• Pick Prospeo if you mainly need verified work emails and mobiles, by API, extension or CSV, and you want a public rate card with no charge for a miss (Prospeo help center, September 2026).
• Pick neither if you pull people and company data by API at volume. Seats, credits and quotes all get awkward there. LeadOcean is one option, covered below.

Side by side

Data and coverage

Seamless.AI claims far more than Prospeo, and neither tells you how many of those records match your list. Seamless.AI lists 2.2B+ contacts, 1.6B+ business emails and 448M+ mobile numbers (Seamless.AI, September 2026). Prospeo's API docs say 200M+ contacts, and its homepage says 143M verified emails (Prospeo, September 2026).

Size is not hit rate. These are vendor claims, not tests. Run the same 200 people through both before you trust either number.

The two tools start from different places. Seamless.AI is built around a rep searching an audience, then researching the contacts they want. Prospeo is built around a person you already know. You send a name and a company website, or a LinkedIn URL, and it returns a profile, an email and, if you ask, a mobile.

Phones are priced differently. Seamless.AI says one credit covers a contact's email and phone together, so a mobile costs the same as an email. Prospeo charges 10 credits per mobile, with the email included (Prospeo help center, September 2026). A phone-heavy pull is far cheaper per record on Seamless.AI, if you can get a price.

API and developer experience

Both tools have a REST API and a hosted MCP server. The shape of the call differs. Seamless.AI researches a contact, then you poll for the result. Prospeo answers in the same response. Placeholders below stand in for real people.

Seamless.AI, research a contact by name and company.

curl -X POST https://api.seamless.ai/api/client/v1/contacts/research \
  -H "Content-Type: application/json" \
  -H "Token: $SEAMLESS_API_KEY" \
  -d '{"contacts":[{"contactName":"Jane Doe","companyName":"Acme Corp"}]}'

The call returns request IDs. You then call GET /contacts/research/poll with those IDs, or take the result by webhook (Seamless.AI docs, September 2026). A record can come back missing, and the docs do not say whether a missing record is charged. One request takes up to 500 records.

Prospeo, enrich a person by name and company website.

curl -X POST "https://api.prospeo.io/enrich-person" \
  -H "X-KEY: $PROSPEO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"only_verified_email": true, "data": {"first_name": "Jane", "last_name": "Doe", "company_website": "acme.com"}}'

The response is synchronous. The flags only_verified_email and enrich_mobile control when credits are spent, and a miss costs nothing (Prospeo enrich docs, September 2026). Prospeo advises its bulk endpoint, up to 50 people per request, for speed.

Limits differ in kind. Seamless.AI allows 60 requests a minute per endpoint for the whole organization, but each research call can carry 500 records. At that size, 1,000,000 records is 2,000 research calls, about 34 minutes of request windows, plus 2,000 search calls in a separate window. The docs give no completion time for an asynchronous job (Seamless.AI docs, September 2026).

Prospeo's limits depend on the plan. Enrich allows 2,000 requests a day on Starter, 5,000 on Growth and 500,000 on Pro (Prospeo rate limits, September 2026). Free plan API access is the one place Prospeo's own pages disagree. The pricing table shows no access, while the help center lists 50 requests a day (Prospeo help center, September 2026). Test a free key before you plan around it.

Pricing

Seamless.AI publishes no dollar price. Prospeo publishes all of its plans. The worked example below uses one credit per record, every lookup a hit. Prices are monthly list first, billed-yearly after.

10,000 records a month

• Seamless.AI: 10,000 contacts is 10,000 credits, the monthly allowance of one Pro license. Add 1,000 credits if each record first comes from a search at 1 credit per 10 results. No public price: the pricing page is a quote form (Seamless.AI pricing, September 2026).
• Prospeo: one Growth seat gives 5,000 credits for $99, and the 5,000-credit add-on is $90. That is 10,000 credits for $189 a month. Billed yearly, 2 Growth seats at $74 give 10,000 credits a month for $148 (Prospeo pricing, September 2026).

1M records a month

• Seamless.AI: 1,000,000 records x 1 credit = 1,000,000 credits. With a search first, add 1,000,000 / 10 = 100,000 credits. A Pro license carries 10,000 credits a month, so that is 100 licenses. The only other route is a bulk credit pool, which is quote only. No public price at 1M (Seamless.AI credit docs, September 2026).
• Prospeo: (1,000,000 - 350,000 add-on credits) / 15,000 per Pro seat = 44 seats x $249 = $10,956, plus the 350,000-credit add-on at $3,500. That is 1,010,000 credits for $14,456 a month. Billed yearly, a steady 1M a month is 67 Pro seats at $2,241, which is $150,348 a year or $12,529 a month, with all credits upfront (Prospeo pricing, September 2026).

Those Prospeo figures are for emails. A mobile costs 10 credits, so 1M mobiles is 10M credits, and no public plan sells that. Prospeo publishes nothing above 350,000 add-on credits a month or 500,000 a year, and extended pricing is enabled on request (Prospeo help center, September 2026).

Credits do not roll over at Prospeo. Unused plan and add-on credits expire at the end of each cycle. Seamless.AI's docs say credits refresh on the contract date and are silent on rollover. Its subscriptions are annual, and cancelling needs 60 days' notice before renewal (Seamless.AI terms, September 2026).

The split is simple. Below about 20,000 records a month, Prospeo costs a few hundred dollars and you can see it before you buy. At 1M, Prospeo's list price is a real number and Seamless.AI's is a sales call. Seamless.AI may well be cheaper per record at that size, since one credit covers email and phone. Ask for the quote and compare.

Where Seamless.AI wins

Seamless.AI is a workspace for reps. It ships a Chrome extension, a dialer, emailing, buyer intent and job change tracking, and says it syncs with 6,000+ tools (Seamless.AI, September 2026). A rep can find a person on LinkedIn and call them from one screen.

It also has the larger claimed database and a cheaper phone model on paper. One credit covers a contact's email and phone, and it lists 448M+ mobile numbers. If your reps call people all day, Seamless.AI does more of the job than Prospeo does.

Where Prospeo wins

Prospeo wins on price clarity. Every plan, add-on and rate limit is public, a miss is free, and re-enriching the same record within 90 days is free (Prospeo help center, September 2026). A solo user pays $49 for 2,000 credits and knows it.

The API is also easier to use. A single synchronous call returns a person with an email, where Seamless.AI needs a research job and a poll. Prospeo has a Chrome extension on every plan and HubSpot and Salesforce sync on Growth and Pro (Prospeo pricing, September 2026). It is the narrower tool, and for finding contact details that is an advantage.

If you need volume through an API

LeadOcean is a people and company data API with a hosted MCP server, with no seats and no credits. Free gives 1,000 records one-off with no card, and Pro is $499 a month flat with the whole database over REST and MCP. Export up to 50,000 rows per request with POST /v1/exports, and call count_leads first because counts are free. It is only a data layer, with an export app but no rep workspace, sequencer or Chrome extension, so reps who prospect all day should still use Seamless.AI or Prospeo. See pricing.

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