# Fiber AI review (2026): the best reverse email lookup we tested

By [Florian Martens](https://pipe0.com/authors/florian-martens) · Published Oct 6, 2026

Source: https://pipe0.com/reviews/fiber
Scoring method: https://pipe0.com/reviews#methodology
Disclosure: pipe0 doesn't buy data from Fiber AI today. We benchmarked it as a candidate for our waterfalls, and the scores come from that benchmark.

> Fiber AI is a people and company data API built for agents, with four MCP servers and a per-call price on every response. In our benchmark it led on email to LinkedIn and on work email.

**Verdict: 4.1/5.** A fast-moving data API for agents that led two of our four contact tests, with cheap per-lookup prices and some of the best agent tooling in the category. The $250 entry plan and slow phone reveals hold it back.

| Criterion | Score | Why |
| --- | --- | --- |
| Ease of use | 3.5/5 | An API first, with a dashboard for search and exports. Through its MCP servers, anyone in Claude or ChatGPT can query it in minutes. |
| Data quality | 4.5/5 | First on email to LinkedIn by a wide margin and first on work email, within a point of the leaders on personal email, mid-pack on mobiles. |
| Pricing value | 4.0/5 | A credit is 2 cents, so a work email costs 4 cents and a phone 6, and misses are free. The cheapest plan is $250 a month with no free tier. |
| API and agent access | 4.5/5 | Four MCP servers, an OpenAPI spec, per-operation docs written for agents, SDKs, webhooks, and a price on every response. |
| **Overall** (mean) | **4.1/5** | |

**Best for:**

- Teams building agents or products on people and company data
- Turning a list of email addresses into LinkedIn profiles
- Developers who want to see what every call cost

**Skip it if:**

- You want a free plan to start
- Phone numbers are your main need
- You need a published security certification before you buy

**Price:** from $250/mo for Prospector, billed annually ($300 billed monthly). No free plan.

## Fiber AI at a glance

- **Founders:** Adi Agashe (CEO) and Neel Mehta (CTO) ([source](https://www.fiber.ai/about))
- **Founded:** 2023, Y Combinator Summer 2023 ([source](https://www.ycombinator.com/companies/fiber-ai))
- **Headquarters:** New York ([source](https://www.ycombinator.com/companies/fiber-ai))
- **Dataset:** 850M+ people, 40M+ companies, and 30M+ jobs, according to Fiber ([source](https://www.fiber.ai/data-api))
- **API:** OpenAPI spec, TypeScript and Python SDKs, webhooks for async jobs ([source](https://api.fiber.ai/docs))
- **Rate limits:** 3,500 a minute for reverse email lookup, 200 for contact reveals ([source](https://docs.fiber.ai))
- **MCP servers:** Four at mcp.fiber.ai, with OAuth or an API key; Claude, ChatGPT, Cursor, Codex, and VS Code ([source](https://docs.fiber.ai/build/mcp))

## Fiber AI in our benchmark

pipe0 ran the same records through every provider it tests (August 2026).

| Test | Records | Coverage | Agreement | Median time | Run |
| --- | --- | --- | --- | --- | --- |
| Email to LinkedIn URL (signup emails) | 150 | 38% | 92% | 7.3 s | 20260804T165645Z-0041 |
| LinkedIn URL to work email (LinkedIn profiles) | 50 | 76% | 59% | 1.6 s | 20260814T124831Z-67f9 |
| LinkedIn URL to personal email (LinkedIn profiles) | 150 | 51.3% | 80% | 3.1 s | 20260814T102434Z-7165 |
| LinkedIn URL to mobile (LinkedIn profiles) | 150 | 64.7% | 69% | 9.7 s | 20260804T202803Z-237d |

### How often Fiber AI agrees with other providers

Email to LinkedIn URL (run 20260804T165645Z-0041).

- LeadMagic (low-cost): Fiber AI and LeadMagic returned the same LinkedIn profile for 19 of 20 people (95%).
- Crustdata (premium): Fiber AI and Crustdata returned the same LinkedIn profile for 14 of 15 people (93%).

- The next best provider in the email to LinkedIn run found 24.7%. Surfe and Amplemarket were not part of that run.
- The work email test ran on 50 profiles, fewer than the others.
- Mobile timing comes from an uncached 150-profile run on the same day; the coverage run was served from cache.
- Samples are small, 50 to 150 records per test, so treat a few points of difference as noise.
- The LinkedIn profile set passed one vendor's resolvability filter, so absolute rates run higher than on a typical list. Comparisons between providers stay fair.
- The signup set is real pipe0 signup emails with no vendor involved in choosing them, a harder and more realistic population than the profile set.
- Agreement is the share of results that match what other providers returned for the same person. It is a proxy for accuracy, not ground truth.

## What is Fiber AI? [#what-is-fiber-ai]

Fiber AI is a data API for people and companies, built in New York by Adi
Agashe and Neel Mehta after Y Combinator's summer 2023 batch. It does the
things a GTM agent needs from one key: search people and companies, enrich a
profile, reveal emails and phone numbers, fetch a LinkedIn profile live,
track job changes, and watch companies for signals. It says it covers 850
million people and 40 million companies.

What sets it apart is how much of it is written for software. Every
operation has its own markdown page for agents, the OpenAPI spec is public,
and every response says what the call cost.

## Where its data is strongest [#where-its-data-is-strongest]

We ran Fiber through the same tests as every other provider, and its
results are uneven in an interesting way: excellent on email, average on
phones.

The standout is the reverse lookup. Given 150 email addresses from real
pipe0 signups, Fiber found the person's LinkedIn profile for 38% of them.
The next best provider in that run found 25%. That gap is large enough to
survive the small sample, and Fiber's answers matched the other providers
92% of the time when both found someone.

On work email from a LinkedIn profile, Fiber found 76% of 50, the highest
of the ten providers in that run. On personal email it found 51% of 150,
within a point of the two leaders. Mobile numbers are where it falls back
to the middle: 65% of 150 profiles, well behind the 96% [Surfe](/reviews/surfe)
reached on the same records.

Fiber also sells a premium phone product at 5 credits instead of 3. On the
same 50 profiles, it found 64% of mobile numbers against 66% for the
standard reveal. Save the credits.

## What it costs [#what-it-costs]

A credit is 2 cents on a subscription. A work or personal email is 2
credits, so 4 cents; a phone number is 3, so 6 cents; and a reveal that
finds nothing is free. Those are low prices for the coverage. Embedded
waterfalls in other tools often charge 8 to 30 cents per email.

The catch is the entry point. The smallest plan is $250 a month billed
annually for 15,000 credits, and there is no free plan, only a trial of 500
credits with a card or 100 through the API without one. A team that needs a
few hundred lookups a month will pay for capacity it doesn't use.

## Built for agents [#built-for-agents]

Fiber runs four MCP servers, each for a different situation: a core server
that discovers and calls any of its 250-odd operations, one with direct
tools for common jobs, one with OAuth for Claude and ChatGPT, and a lite
version. It is listed in the official MCP registry and ships a Claude Code
plugin.

Rate limits are generous where it matters: 3,500 reverse lookups a minute
and 200 contact reveals. Long jobs run asynchronously with signed webhooks.
The one thing to plan around is speed on phones, where a reveal can take
ten seconds or more, and Fiber itself recommends a two-minute timeout.

## Fiber AI and pipe0 [#fiber-ai-and-pipe0]

pipe0 doesn't use Fiber today. We added it to our benchmark as a candidate
for our waterfalls, and the numbers above are from that work. Its reverse
lookup is the strongest result we have for that path.

## Who should buy Fiber AI [#who-should-buy-fiber-ai]

Buy Fiber if you are building an agent or a product that needs people data
and contact details, especially if you start from email addresses. The
price per lookup is low and the tooling is among the best we have seen.

Look elsewhere if you need a free plan, if your volume is small, or if phone
numbers are the main thing you buy. For mobiles, Surfe found the most in our
tests; for company signals, [Crustdata](/reviews/crustdata) goes deeper.

## Fiber AI pros and cons

### Pros

- **The best reverse email lookup we measured.** From an email address, Fiber found the person's LinkedIn profile for 38% of 150 signups. The next provider in that run found 25%, and Fiber's answers matched the others 92% of the time.
- **Strong on email.** It found a work email for 76% of 50 profiles, the highest in that run, and a personal email for 51% of 150, within a point of the best.
- **Cheap per lookup.** A credit costs 2 cents on a subscription. A work or personal email is 2 credits, a phone 3, and a reveal that finds nothing costs nothing.
- **Agent tooling done properly.** Four MCP servers for different clients and auth needs, docs for every operation as markdown, an OpenAPI spec, TypeScript and Python SDKs, and webhooks for long jobs.

### Cons

- **No free plan.** Plans start at $250 a month billed annually. Trials give 500 credits with a card, or 100 through the API without one.
- **Slow phone reveals.** Phone and personal email reveals took a median of 9.7 and 3.1 seconds in our test, and Fiber recommends a two-minute timeout.
- **Premium phone added nothing.** On the same 50 profiles, the 5-credit premium phone product found 64% of mobile numbers against 66% for the 3-credit standard reveal.
- **No public compliance claims.** We found no SOC 2, ISO 27001, or GDPR statement on Fiber's site, docs, or privacy policy. Ask before you send it personal data.

## Fiber AI pricing

| Plan | Price | What you get |
| --- | --- | --- |
| Prospector | $250/mo annual, $300 monthly | 15,000 credits a month. |
| Growth | $750/mo annual, $900 monthly | 50,000 credits a month, twice the rate limits, Slack support. |
| Enterprise | $2,000/mo annual, $2,400 monthly | 150,000 credits a month, custom rate limits and endpoints. |

- A credit is 2 cents on a subscription and 3 cents as a pay-as-you-go top-up.
- A work or personal email costs 2 credits, a phone number 3, all contact details 5, premium phone 5, and a reverse email lookup 2 (1 on the lite endpoint).
- Reveals that find nothing and reverse lookups without a match are not charged. A live LinkedIn fetch costs 2 credits even when the profile doesn't exist.
- Every response reports what the call cost, and the balance endpoint returns your account's own price list.

Prices as of Oct 6, 2026, from https://www.fiber.ai/pricing.

## Fiber AI alternatives

- [pipe0](https://pipe0.com/enrichment-api): You want contact data from a waterfall across 50+ providers, with no monthly minimum beyond a $49 plan.
- [Crustdata](https://pipe0.com/reviews/crustdata): You need deep company data, such as headcount, hiring, and web traffic, with live lookups and watchers.
- [Surfe](https://pipe0.com/reviews/surfe): Mobile numbers are the priority. Surfe found the most in our benchmark.
- [Hunter](https://pipe0.com/reviews/hunter): You only need work emails from names and domains, on a free or cheap plan.

## FAQ

### What is Fiber AI?

Fiber AI is a people and company data API for AI agents and products. It covers search, enrichment, contact details, live LinkedIn fetches, job changes, and company signals, with MCP servers for Claude, ChatGPT, Cursor, and other clients.

### How much does Fiber AI cost?

Plans start at $250 a month billed annually for 15,000 credits, or $300 monthly. A credit is 2 cents. A work email costs 2 credits, a phone number 3, and lookups that find nothing are free. There is no free plan, only a trial.

### How good is Fiber's data?

In our benchmark, Fiber found the LinkedIn profile behind 38% of 150 email addresses, far ahead of every other provider in that run, and a work email for 76% of 50 profiles. Its mobile coverage was mid-pack at 65%.

### Does Fiber AI have an MCP server?

Yes, four, at mcp.fiber.ai: a core server that can call any operation, a server for common operations with an API key, a full server with OAuth, and a lite server. Setup guides cover Claude, ChatGPT, Cursor, Codex, and VS Code.

### Fiber AI or Crustdata: which should I choose?

Choose Fiber for contact data and reverse email lookups, where it led our benchmark. Choose Crustdata for deep company data such as headcount trends, hiring, and web traffic, and for watchers that track changes.