Head to head
FullContact vs Seamless.AI
As a data enrichment API, FullContact rates higher on the APIbenchmarks Index, 68.4 to 68.3, a 0.1-point gap. Here is how they compare on each criterion.
Criterion by criterion
| Criterion | FullContact | Seamless.AI |
|---|---|---|
| Documentation & DX | ||
| Reliability | ||
| Ecosystem & SDKs | ||
| Accessibility | ||
| APIbenchmarks Index | 68.4 | 68.3 |
Specifications
| FullContact | Seamless.AI | |
|---|---|---|
| Best for | Identity resolution / Identity Graph | Prospecting teams wanting UI plus API and MCP |
| Free tier | 100 API calls/mo (Developer plan) | Free plan (50 lifetime credits per third party; API eligibility unconfirmed) |
| Pricing | Per matched API call | Per credit; sales-led Pro/Enterprise |
| Official SDKs | 7 languages | 6 languages |
Is FullContact better than Seamless.AI?
On the APIbenchmarks Index, FullContact rates higher (68.4 vs 68.3). It leads on the four weighted criteria, but price is reported separately, so the best choice still depends on your budget.
Verdict in one line
FullContact leads by 0.1 points (68.4 vs 68.3) and wins 1 of 4 criteria; Seamless.AI wins 3.
Winner by criterion
| Criterion | Winner | ||
|---|---|---|---|
| Documentation & DX | 70 | 76 | |
| Reliability | 70 | 74 | |
| Ecosystem & SDKs | 62 | 68 | |
| Accessibility | 72 | 50 |
Choose FullContact if… / choose Seamless.AI if…
- →accessibility matters most to you (72 vs 50)
- →you need broad SDK coverage (7 official SDKs vs 6)
- →your use case matches its focus: identity resolution / identity graph
- →documentation & dx matters most to you (76 vs 70)
- →reliability matters most to you (74 vs 70)
- →ecosystem & sdks matters most to you (68 vs 62)
- →your use case matches its focus: prospecting teams wanting ui plus api and mcp
Pricing side by side
- Model
- Per matched API call
- Free tier
- 100 API calls/mo (Developer plan)
- Developer (Free)$0
- Growth$99/month
- Basic~$500/month
- Premium~$2,000/month
- Enterprise$10,000+/month (custom)
- Model
- Per credit; sales-led Pro/Enterprise
- Free tier
- Free plan (50 lifetime credits per third party; API eligibility unconfirmed)
- Free$0
- ProContact sales (third-party: about $4,740-$9,000/yr for 5 users)
- EnterpriseCustom
Vendor-published pricing, verified 2026-06-27 (FullContact) and 2026-10-07 (Seamless.AI).
SDK and language coverage
Both · 1
Postman collection
Only FullContact · 6
Go (official V3 client)Java 8 (official V3 client)Java 11+ (official V3 client)Python (official V3 client)Ruby (archived/legacy)PHP (archived/legacy)
Only Seamless.AI · 5
REST API (v1/v2)OpenAPI YAML/JSONMCP servercurl, Python and Node examplesNo official language SDKs found
Strengths and weaknesses
- +Multi-field enrichment: accepts many identifier types (email, phone, name+address, social URLs/usernames, MAIDs, plus Resolve PersonIDs) to lift match rates
- +Deep attribute coverage, 900+ appendable data attributes via Person Insights Bundles (demographics, household, employment history, affinities, shopping habits)
- +Tunable confidence: ML 'Belief Vector' lets callers set confidence thresholds per request to balance precision vs. match rate
- –Real-world match rates often far below the advertised 93%, reviewers report ~40-50%, especially outside the U.S.
- –Data-quality complaints of false positives in age, employment, and education fields, with no data-freshness timestamps on attributes
- –Rate limit (~600 queries/min) too low for large batch enrichment jobs
- +Modern async API with webhooks or polling plus OpenAPI YAML/JSON specs
- +MCP server with 57 tools documented for Claude, Cursor, VS Code and ChatGPT
- +Published rate limits and simple credit rules (search 1 credit per 10 results; polling free)
- –Plan eligibility for the API is unclear and sources conflict
- –60 requests/min per endpoint, restrictive for bulk jobs
- –Pro and Enterprise pricing is sales-led
FullContact vs Seamless.AI: questions
- Which has better documentation, FullContact or Seamless.AI?
- Seamless.AI scores higher on documentation and developer experience: 76 vs 70 out of 100.
- Which is more reliable, FullContact or Seamless.AI?
- Seamless.AI scores higher on reliability: 74 vs 70 out of 100.
- Do FullContact and Seamless.AI have a free tier?
- FullContact: yes (100 API calls/mo (Developer plan)). Seamless.AI: yes (Free plan (50 lifetime credits per third party; API eligibility unconfirmed)).
- How are FullContact and Seamless.AI priced?
- FullContact: Per matched API call. Seamless.AI: Per credit; sales-led Pro/Enterprise.
- Which has more official SDKs?
- FullContact lists 7 official SDKs, Seamless.AI lists 6.