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

Apollo.io and Seamless.AI both sell B2B contact data inside a sales platform, but they price it in opposite ways. Apollo publishes a price per seat and grants credits with each seat. Seamless.AI publishes credits but no dollar price.

Verdict

• Pick Apollo if you want a price you can read, a free plan you can test on, and an API with published limits. It also runs sequences and a dialer next to the data, and its MCP server works on any plan.
• Pick Seamless.AI if mobile numbers matter most. One credit returns a contact's email and phone together, and it claims 448M+ verified mobiles. You will get the price from sales, not from a page.
• Pick neither if you need volume through an API at a price you can read. Apollo at 1M records is 250 to 400 seats, and Seamless.AI has no public 1M price. LeadOcean is one option: Pro is $499 a month, flat.

Side by side

Data and coverage

Seamless.AI claims far more data. It lists 2.2B+ verified contacts and 121M+ companies, against Apollo's 240M contacts and 30M companies. Both are the vendors' own numbers, and a bigger claim is not a better match rate on your list.

Only Seamless.AI publishes email and phone counts. It claims 1.6B+ verified business emails and 448M+ verified mobiles (Seamless.AI API page, September 2026). Apollo prints neither, so you cannot compare coverage on paper.

Phones are where the products differ most. At Apollo, a phone number is 8 credits and an email is 1. A person with both costs up to 9 credits (Apollo API pricing, September 2026). At Seamless.AI, one credit covers the contact's email and phone together (Seamless.AI docs, September 2026).

The products also differ beyond the data. Apollo is a workspace with sequences, a dialer and pipeline tools. Seamless.AI sells prospecting, bulk credits, job changes and buyer intent, and prices them by inquiry (Seamless.AI pricing, September 2026).

Test on your own list before you buy. Apollo Free gives 75 credits a month and Seamless.AI Free gives 50 credits once. Run the same 30 people through each and compare the match rate and the email status.

API and developer experience

Both are REST APIs with an official MCP server. The difference is the flow. Apollo answers an enrichment call in the response. Seamless.AI makes you submit a job and poll for it.

Apollo takes the key in an x-api-key header. The enrichment call is POST /api/v1/people/match:

curl --request POST \
  --url "https://api.apollo.io/api/v1/people/match?linkedin_url=https://www.linkedin.com/in/jane-doe" \
  --header "x-api-key: $APOLLO_API_KEY" \
  --header "Content-Type: application/json"

The call costs 1 to 9 credits: 1 for an email, plus 8 if a mobile comes back. A request that finds nothing credit-consuming costs 0. Phones are off by default. You set reveal_phone_number and give a webhook URL, and the phone arrives there later (Apollo docs, September 2026).

Seamless.AI takes the key in a Token header. You start a research job. It returns an HTTP 202 with requestIds (Seamless.AI docs, September 2026):

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", "title": "CTO" }
    ]
  }'

Next, call GET /contacts/research/poll with those requestIds. Or take the result by webhook. A poll ends in done, error, missing or duplicate. The docs do not say whether a missing record is charged, and they do not say how long a job takes (Seamless.AI docs, September 2026).

Rate limits scale in different ways. Apollo's are per team and per endpoint, across three windows at once. Paid plans get 1,000 enrichment requests a minute with no hourly or daily cap, and 200 search requests a minute (Apollo rate limits, September 2026).

Seamless.AI's default is 60 requests a minute per endpoint, shared by every key and user in the organization. Search, research and poll each get their own window (Seamless.AI docs, September 2026). Batches are larger, though: 500 records per research request against Apollo's 10 per bulk call.

On credits, a Seamless.AI search costs 1 credit per 10 results returned, and research costs 1 credit per record. Polling and reading org data cost nothing. Apollo's credits attach to enrichment, at 1 to 9 per person (Seamless.AI docs; Apollo API pricing, September 2026).

On MCP, both run hosted servers with OAuth. Apollo's works on any plan, and enrichment through it spends the same credits. Seamless.AI's has 57 tools. Its search tools use no credits, its research tools do, and MCP access must be enabled on the account (Apollo docs; Seamless.AI MCP docs, September 2026).

Pricing

Apollo charges per seat, and each seat carries a fixed monthly credit grant. Seamless.AI charges in credits, and sells them by quote. Credits are the only unit you can compare across the two.

At 10,000 records a month

Take 10,000 work emails from Apollo. That is 10,000 credits at 1 credit each. On monthly billing, Basic gives 2,500 credits per seat at $65, so 4 seats x $65 = $260 a month. Professional needs 3 seats for 12,000 credits: 3 x $99 = $297 (Apollo pricing, September 2026).

On yearly billing, Basic is $49 a seat. So 4 seats x $49 = $196 a month, or $2,352 a year. Apollo credits expire at the end of each billing cycle.

Add phones and the sum moves. If all 10,000 contacts return a mobile, that is 9 credits each, or 90,000 credits. Then 90,000 / 4,000 = 22.5, so 23 Professional seats x $99 = $2,277 a month.

For Seamless.AI, 10,000 contacts is 10,000 credits, with email and phone included. A Pro license carries 10,000 credits a month, so that is one Pro license. If every record first comes from a search at 1 credit per 10 results, add 1,000 credits and you need two licenses (Seamless.AI credit docs, September 2026). Seamless.AI publishes no price for a Pro license, so there is no dollar figure here.

At 1M records a month

For Apollo, 1,000,000 work emails is 1,000,000 credits. On monthly billing, Professional gives 4,000 credits per seat, so 1,000,000 / 4,000 = 250 seats x $99 = $24,750 a month. On yearly billing, Basic gives 2,500 a month, so 400 seats x $49 = $19,600 a month, or $235,200 a year (Apollo pricing, September 2026).

Two caveats apply. Apollo prints no price for add-on credits, so a cheaper seats-plus-add-ons path cannot be priced. Whether Apollo allows 250 to 400 self-serve seats is also not stated.

For Seamless.AI: no public 1M price. The same pull is 1,000,000 research credits, or 1,100,000 with a 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). We do not multiply a rate out to 1M and call it a price.

Time is the other cost. At 500 records a call and 60 calls a minute, 1M records is 2,000 research calls, about 34 minutes of request windows, plus the search pages. Job completion time is not documented.

Where Apollo.io wins

• A price you can read. It is a large number at 1M, but it is published. Seamless.AI's is not.
• A real free plan. 75 credits every month, against 50 credits once.
• Faster enrichment limits. 1,000 enrichment requests a minute on paid plans, against 60 a minute at Seamless.AI.
• Synchronous enrichment. One call, one answer, with phones by webhook. No job to poll for an email.
• MCP on every plan. The server works on Free, and API access comes with every plan.

Where Seamless.AI wins

• Phones. One credit covers email and phone together, against up to 9 credits at Apollo.
• A bigger claimed dataset. 2.2B+ contacts and 448M+ mobiles, against Apollo's 240M contacts.
• Published coverage counts. It states email and mobile totals. Apollo does not.
• Bigger batches. 500 records per research request against Apollo's 10.
• More API keys. An organization can hold 25 persistent keys and 25 OAuth connections (Seamless.AI docs, September 2026).

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 and a limit of 100 requests per second per key (LeadOcean pricing, September 2026).

For bulk work, POST /v1/exports returns up to 50,000 rows per request. The app also has an Exports page with a filter builder and CSV download (LeadOcean exports docs, September 2026). There is no sequencer, dialer or Chrome extension. If your reps live in Apollo or Seamless.AI, keep it for that. See the Apollo alternative page for a line-by-line version.

FAQ