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Fiber

Sales and recruiting data, built for agents

Data & Discovery
For AI agents
MCPAPINative readiness
About

What is Fiber

Fiber AI provides data APIs that let sales and recruiting agents search across 850M+ professionals and 40M+ companies, enrich contact records in real time, and verify emails through four layers of bounce detection. It's built for SDRs, BDRs, GTM engineers, and founders at mid-market and enterprise companies who need programmatic access to prospect data without hitting LinkedIn's walls. The standout capability is its ability to identify companies by specific promotion patterns, headcount growth trajectories, or accelerator funding history — filters that most prospecting databases don't expose at the API level. The MCP server makes it directly callable by AI agents, which is rare in this category. That said, at $300–$2,400/month on a credit-based model, teams with low or unpredictable outbound volume may find the cost structure hard to justify before they've validated their ICP.

Data & Discovery
Capabilities

Key features

Prospecting database

searchable B2B contact + company directory

AI capabilities

autonomous multi-step actions, per-prospect AI research

Data

verified emails, mobile phones, intent signals, real-time enrichment

Also ships

official SDK

Outbound webhooks

event-driven integrations

Our verdict

Vanderbuild take

Fiber AI sits at the intersection of prospecting database, data enrichment, and email finder — and it's one of the few tools in this category built from the ground up for SDRs, GTM engineers, and founders who want to drive outbound from code, not just a UI. If you're serious about agentic outbound, this is non-negotiable: the native MCP server makes it a first-class orchestration layer for AI agents, not an afterthought bolted on via webhook. Pricing starts at $300/month on a credit model, but the tiers scale to $2,400/month for enterprise volume — expect procurement involvement if you're running this at scale. The honest limitation is that the credit-based billing, where you only pay for successful data calls, sounds clean but can get unpredictable as query volume grows, and teams without a dedicated GTM engineer may struggle to extract full value from the API surface without significant setup time.

Mateusz Sekta
Founder, vanderbuild
Learn more

Our Resources

The wedge

Agentic stack profile

MCP server
Yes

Live MCP server — agents can call this tool directly.

The MCP server connects LLMs and agents to Fiber AI's database of over 40 million companies and 850 million people.

Open MCP →
API
REST

Programmatic access available.

REST API — straightforward to call from any agent or workflow tool. Rate limits and auth vary by plan.

API docs →
Agentic readiness
Native

Built for agents from the ground up.

MCP server + agent-friendly API + at least one autonomous workflow out of the box. The bar for 'Native' is high — only a handful of tools currently qualify.

Stack role
Data source · Enricher

Where this tool slots into an agentic pipeline.

Plays the role of Data source + Enricher in an agentic pipeline. Use it to source contacts, companies, and the raw inputs an agent needs to act; add firmographic, technographic, and signal data to a lead row on the fly.

Compare

Fiber alternatives

Tools that solve a similar problem — compared at a glance.

Fiber(this tool)
Pricing
Custom
Budget
$$$$
Best for
SDR / BDR, GTM Engineer
Readiness
Native
MCP
Yes
API
REST
Apollo
Pricing
Freemium
Budget
$$
Best for
SDR / BDR, Account Executive
Readiness
Native
MCP
Yes
API
REST
Lusha
Pricing
Freemium
Budget
$$
Best for
SDR / BDR, RevOps
Readiness
Native
MCP
Yes
API
REST
Answers

Frequently asked questions

Does Fiber have an MCP server?

Yes — Fiber exposes a Model Context Protocol server. The MCP server connects LLMs and agents to Fiber AI's database of over 40 million companies and 850 million people. See the MCP docs at https://docs.fiber.ai/article/using-mcp-in-llms.

Does Fiber have a public API?

Yes — Fiber ships a REST API. Docs: https://api.fiber.ai/docs.

How much does Fiber cost?

Fiber: pricing is custom, expect enterprise tier ($$$$) spend. Full pricing page: https://fiber.ai/pricing.

Who is Fiber best for?

Fiber is built for SDR / BDR, GTM Engineer, Founder. Fits Mid-market (50-500), Enterprise-sized teams.

How well does Fiber fit an agentic sales stack?

Tier: Native. Has both an MCP server and an agent-friendly API — drops into an agentic stack with minimal glue code.