Top AI Engineer Staffing Companies

Index.dev vs Harnham: full comparison for 2026

Quick verdict

Index.dev (4.2/5) edges ahead of Harnham (3.7/5) overall. Index.dev is the better choice for startups that want a 30-day refundable trial before committing to a remote ML engineer. Harnham is the stronger option for companies hiring permanent data or ML staff in the UK or U.S. through a specialist agency. The right choice depends on your project size, budget, and required tech stack.

Index.dev vs Harnham: head-to-head summary

Criterion Index.dev Harnham
Founded 2019 2006
HQ London, United Kingdom London, United Kingdom
Team size 30,000+ network 100–500
Rating 4.2 / 5 3.7 / 5
Primary differentiator A 30-day trial with full refund on every placement Twenty years of recruiting only in data and analytics
Pricing model Monthly rate per engineer; direct-hire fee option; 30-day trial with refund; rates on request Placement fee for permanent hires; contractor day or hourly rates; rates on request
Min. engagement Not published Not published
Primary tech stack Python, PyTorch, TensorFlow Python, SQL, Spark
Industries served SaaS, Fintech, E-commerce, Healthcare, AI labs Financial services, Retail, Healthcare, Media, Technology

Index.dev vs Harnham: overview

Index.dev

Index.dev is a London company, founded in 2019 according to its own job ads, trading under the legal name Index Soft Limited. It calls itself an AI-first engineering talent platform. Its main network has more than 30,000 engineers in Latin America and Central and Eastern Europe, and a separate AI unit supplies Master's and PhD-level people for LLM fine-tuning and RAG work. Every engineer goes through five stages of vetting run by people, including a live screening call and technical validation, and Index.dev says about 1% are accepted. All placements come with a 30-day trial and a full refund if the match fails.

Harnham

Harnham has recruited for data and analytics roles since 2006 from London, with offices in the U.S. including New York and San Francisco. It places data engineers, data scientists and ML engineers on contract or permanent terms and runs a graduate training arm, Rockborne. As a recruitment agency, it screens through consultants who specialise in data hiring rather than through practising engineers, and contractors are not managed after placement the way a staffing firm's employees are. That makes it better for permanent hires than for managed augmentation.

Services and capabilities: Index.dev vs Harnham

Capability Index.dev Harnham
ML engineers ✓ ✓
LLM / GenAI engineers ✓ ✗
AI agent developers ✗ ✗
MLOps engineers ✗ ✗
Computer vision engineers ✗ ✗
NLP engineers ✗ ✗
Data engineers ✗ ✓
Engineer-led technical screen ✗ ✗
Fractional / part-time experts ✗ ✗
Trial before commitment ✓ ✗
Nearshore time-zone overlap ✓ ✗
Direct hire option ✓ ✓

Tech stack comparison: Index.dev vs Harnham

Framework / platform Index.dev Harnham
PyTorch ✓ N/A
TensorFlow ✓ N/A
LangChain ✓ N/A
Hugging Face ✓ N/A
OpenAI ✓ N/A
AWS ✓ ✓
Azure N/A ✓
Google Cloud ✓ N/A
Databricks N/A ✓
Kubernetes N/A N/A

Pricing comparison: Index.dev vs Harnham

Criterion Index.dev Harnham
Minimum engagement Not published Not published
Engagement models Dedicated engineer, Dedicated team, Direct hire, Trial period Direct hire, Contract-to-hire, Freelance contract
Rate transparency Not public Not public
Price tier Mid-market Mid-market

Target audience comparison: Index.dev vs Harnham

Dimension Index.dev Harnham
Best company size Startup to mid-market Startup to mid-market
Best industries SaaS, Fintech, E-commerce Financial services, Retail, Healthcare
Best use cases Trialling a Latin American ML engineer for a month before committing, Hiring a PhD-level specialist to fine-tune an open-source LLM Hiring a permanent head of data science in London, Placing a contract data engineer for six months
Typical project type Dedicated engineer Direct hire

Index.dev vs Harnham: pros and cons

Index.dev
+ The 30-day refundable trial is the most generous published trial on this page
+ A separate AI unit for advanced work such as fine-tuning
+ Clients can hire directly as well as contract
- Vetting is human-led but not specifically run by ML engineers
- Network figures and acceptance rates are company claims
- Founding date only appears in job listings
Harnham
+ Long specialist history in data recruiting
+ Offices in the UK and several U.S. cities
+ Both contract and permanent hiring
- Screening by recruitment consultants, not engineers
- Contractors are not managed after placement
- Headcount estimates vary

Who should choose Index.dev?

A typical fit: trialling a Latin American ML engineer for a month before committing.

A 30-day trial with full refund on every placement. Minimum engagement is not publicly disclosed. Works best with clients in SaaS, Fintech, E-commerce, Healthcare, AI labs.

Who should choose Harnham?

A typical fit: hiring a permanent head of data science in London.

Twenty years of recruiting only in data and analytics. Minimum engagement is not publicly disclosed. Works best with clients in Financial services, Retail, Healthcare, Media, Technology.

Decision matrix: Index.dev vs Harnham

Your situation Recommended choice
You want a working engineer, not a recruiter, to run the technical screen Neither documents an engineer-led screen; run your own technical interview
You need one specialist for a few days a week Neither advertises part-time experts; ask about reduced hours
You need several engineers working as one team Neither lists dedicated teams; check team size before signing
You want to test an engineer before committing Index.dev
Your budget is at the lower end Compare: Index.dev (Not published) vs Harnham (Not published)
Your team works U.S. hours Index.dev
You may want to hire the engineer permanently later Both; Index.dev rates higher overall

Use case fit: Index.dev vs Harnham

Use case Index.dev fit Harnham fit Winner
Trialling a Latin American ML engineer for a month before committing Strong Limited Index.dev
Hiring a PhD-level specialist to fine-tune an open-source LLM Strong Strong Both equally
Hiring a permanent head of data science in London Strong Strong Both equally
Placing a contract data engineer for six months Limited Strong Harnham

Verdict: Index.dev vs Harnham

Index.dev (4.2/5) is the stronger overall choice for most AI Engineer Staffing projects. A 30-day trial with full refund on every placement.

Harnham (3.7/5) is worth a look if you need placing a contract data engineer for six months. If your situation matches that, Harnham is a competitive option.

Related comparisons

Index.dev vs Harnham FAQ

Is Index.dev better than Harnham?

Index.dev (4.2/5) scores higher overall, but "better" depends on your use case. Index.dev's strongest advantage: the 30-day refundable trial is the most generous published trial on this page. Harnham's strongest advantage: long specialist history in data recruiting.

How do Index.dev and Harnham differ in pricing?

Index.dev uses monthly rate per engineer; direct-hire fee option; 30-day trial with refund; rates on request pricing. Harnham uses placement fee for permanent hires; contractor day or hourly rates; rates on request pricing. Neither firm publishes a full rate card; a discovery call is required for project-specific quotes.

Which is better for enterprise: Index.dev or Harnham?

Harnham is the larger team and typically the better enterprise-scale choice. For very large programmes, verify team size and compliance coverage directly with each company before shortlisting.

What are the main differences between Index.dev and Harnham?

Index.dev's primary differentiator is: a 30-day trial with full refund on every placement. Harnham's primary differentiator is: twenty years of recruiting only in data and analytics. They also differ in team size (30,000+ network vs 100–500), minimum engagement (Not published vs Not published), and primary industries served (SaaS, Fintech vs Financial services, Retail).

Verify all details directly with each company before making a decision.