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

BlitzAPI is the better buy if you work in code and want a published plan list. Seamless.AI is the better buy if reps need a sales app and a large pool of mobile numbers. The two tools sell different things. BlitzAPI sells API calls on a flat monthly plan. Seamless.AI sells credits inside seat licenses.

All figures below were checked in September 2026, each with its source link. Where a vendor publishes nothing, the page says so.

Verdict

• Pick BlitzAPI if you call an API from code and want a flat monthly fee. Plus is $499 a month for verified work emails on accounts opened by September 30, 2026, and the docs are public. Prices for newer accounts are not published yet (BlitzAPI pricing, September 2026). Lookups return in one call.
• Pick Seamless.AI if your reps need the sales app and a large pool of mobile numbers outside the US. It claims 448M+ verified mobile numbers, against BlitzAPI's US-only 45M+ (Seamless.AI API page, September 2026). Expect to talk to sales for the price.
• Pick neither if you want an MCP server that returns records, a CSV export, and email plus phone on one flat plan. LeadOcean covers that. It has no sales app and no job postings data.

Side by side

Data and coverage

Seamless.AI claims the bigger database. BlitzAPI publishes a smaller one, with narrower phone coverage. Treat both as vendor claims. Neither company publishes how it counts a contact.

BlitzAPI lists 550M+ profiles, 65M+ companies, 65M+ verified work emails and 45M+ US phone numbers (BlitzAPI docs, September 2026). Its email addresses are proven against live mail servers and re-tested at least every 30 days. It also lists 100M+ job postings.

Seamless.AI claims 2.2B+ verified contacts, 448M+ verified mobile numbers and 121M+ companies (Seamless.AI API page, September 2026). Its homepage claims 1.6B+ verified business emails (Seamless.AI, September 2026).

Phones are the clearest gap. BlitzAPI's numbers are US only and sit on the $599 Full plan. On Seamless.AI one credit covers a contact's email and phone together (Seamless.AI docs, September 2026). If you call outside the US, Seamless.AI is the only one of the two that claims to help.

Search depth differs too. BlitzAPI's Find People returns 50 results a page and stops at 50,000 results per query (BlitzAPI docs, September 2026). Seamless.AI contact search takes 39 filters and modifiers and returns up to 500 contacts a page (Seamless.AI docs, September 2026).

Run the same 100 lookups in both before you trust any size claim. Match rate on your own list beats a vendor's headline count.

API and developer experience

BlitzAPI is the simpler API. One request returns one answer. Seamless.AI splits the work into search, research and poll, which suits a job queue more than a lookup in a form handler.

BlitzAPI's work email lookup takes a LinkedIn URL and returns found, the email and a fair_usage block with your remaining volume (BlitzAPI docs, September 2026). This is the request shape from its docs, with a placeholder profile:

curl -X POST "https://api.blitz-api.ai/v2/enrichment/email" \
  -H "Content-Type: application/json" \
  -H "x-api-key: $BLITZAPI_API_KEY" \
  -d '{"person_linkedin_url":"https://www.linkedin.com/in/jane-doe"}'

Seamless.AI research starts a job and returns request IDs with an HTTP 202. You then poll for the result, or receive it by webhook (Seamless.AI docs, September 2026). This is the request shape from its docs, with placeholders:

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"}]}'

The poll is a second call to GET /contacts/research/poll with the requestIds. Poll every 2 to 5 seconds, and handle a 429 by reading X-RateLimit-Reset (Seamless.AI docs, September 2026).

Rate limits favour BlitzAPI on paper only. It runs 50 requests per second per endpoint for accounts opened by September 30, and the standard rate is 5 (BlitzAPI pricing, September 2026). Seamless.AI defaults to 60 requests a minute per endpoint, shared by every key and user in the organization. Custom limits need a sales call.

For agents, Seamless.AI wins. Its MCP server has 57 tools. Search tools use no credits and research tools do (Seamless.AI MCP docs, September 2026). BlitzAPI's MCP server answers questions about its docs and cannot search people (BlitzAPI docs, September 2026).

Pricing

BlitzAPI publishes dollars and Seamless.AI publishes credits. That is the whole comparison. Prices below use the monthly list first, with a billed-yearly figure after it where one exists. Neither vendor publishes a billed-yearly dollar figure.

At 10,000 records a month. BlitzAPI is one plan. Plus is $499 a month for verified work emails, Core is $399 without emails, and Full is $599 with US phones (BlitzAPI pricing, September 2026). Only emails it finds count as results, so 10,000 lookups return at most 10,000.

Seamless.AI at 10,000 is one Pro license on credits alone. Pro carries 10,000 credits a month and contact research costs 1 credit each (Seamless.AI credit docs, September 2026). If every record first comes from a search, add 1 credit per 10 results. That is 10,000 + 1,000 = 11,000 credits, or 2 licenses. The dollar price is not published.

At 1M records a month. For an account opened by September 30, 2026, BlitzAPI is still $499 a month at list. 1,000,000 results is under the 15,000,000 a month fair use line, so one Plus plan covers it: $499 x 1 month = $499 (BlitzAPI pricing, September 2026). Time is the other cost. 1,000,000 / 50 per second is 20,000 seconds, about 5.6 hours. At the standard 5 per second it is 200,000 seconds, about 2.3 days.

Seamless.AI has no public 1M price. 1,000,000 contact researches is 1,000,000 credits, or 1,100,000 with a search first. At 10,000 credits per Pro license that is 100 licenses, or 110. Both routes are quote only (Seamless.AI docs, September 2026). Do not multiply a credit price out to 1M. Ask sales for the bulk pool price.

Seamless.AI's call time is shorter than you might fear. A search page returns up to 500 contacts and one research request takes up to 500 records. So 1,000,000 / 500 = 2,000 calls, about 34 minutes at 60 requests a minute, for search and for research in separate windows. Async completion time is not documented.

Two cautions. BlitzAPI's $399, $499 and $599 prices, the 50 requests per second and the 15,000,000 line apply to accounts opened by September 30, 2026 (BlitzAPI Terms, September 2026). Prices for later accounts are not published. Seamless.AI subscriptions are annual, sales are final, and cancelling needs 60 days' notice before renewal (Seamless.AI terms, September 2026).

For other Seamless.AI matchups, see Seamless.AI vs UpLead, Seamless.AI vs SalesIntel and Seamless.AI vs LeadIQ.

Where BlitzAPI wins

• A published plan list. You can read the launch-offer plans before you talk to anyone. Seamless.AI's pricing page is a quote form.
• A flat bill at volume. On launch-offer accounts, 1M email results fit inside one $499 plan at list, with no credit meter.
• One synchronous call. No job to start and no poll to run.
• No annual contract. BlitzAPI plans are billed monthly and cancel any time (BlitzAPI pricing, September 2026).

BlitzAPI's weak points are US-only phones, no documented bulk export and an MCP server that only reads docs. Core, Plus and Full also carry no SLA (BlitzAPI FAQ, September 2026).

Where Seamless.AI wins

• Size and mobile numbers. It claims 2.2B+ verified contacts and 448M+ verified mobile numbers.
• A real MCP server. Agents can search and research records through 57 tools, which BlitzAPI cannot match.
• A sales app. Reps get a Chrome extension, calling and buyer intent in one place (Seamless.AI, September 2026). BlitzAPI is an API only.
• Credit back on invalid emails. Seamless.AI says the credit for an invalid email is refunded automatically (Seamless.AI, September 2026).

Seamless.AI's weak points are the missing price, the async flow and a limit shared by the whole organization. Contract terms are annual and strict.

If you need volume through an API

LeadOcean is a third option if neither above fits. The Free plan gives you 1,000 records, one-off, with no card. Pro is $499 a month, flat, with unlimited searches, enrichments and lookups, and no credits or per-record price (LeadOcean pricing, September 2026).

It holds 693M people, 366M with an email and 166M with a phone number, plus 63M companies. The same REST API and a hosted MCP server with 12 tools run on every plan. The MCP server searches, enriches and exports records (LeadOcean MCP docs, September 2026).

For bulk pulls, POST /v1/exports returns up to 50,000 rows per request. The app has an Exports page too (LeadOcean exports docs, September 2026). 1M rows is 20 requests over two days. LeadOcean has no sales app and no job postings data, so a rep team keeps Seamless.AI for calling. See pricing for the detail.

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