Tessl

Tessl helps AI agents stay reliable and aligned by grounding their work in specs.

AI agents Developer tools and cloud

Latest funding

$125M Series A · November 14, 2024

Led by Index Ventures · Source: techcrunch.com

Latest round on record: Series A, June 2026, amount undisclosed.

All 2 rounds ↓

Website: tessl.io.

X: @tessl_io · 1,217 followers.

LinkedIn: tesslio.

Categories: AI agents Developer tools and cloud.

Sectors: Artificial Intelligence (AI), Software, Software Engineering.

Stage: Series A.

Based in: London, United Kingdom.

Founded: 2024.

Last round: Jun 3, 2026 · 165 days ago.

Headcount: 11–50 employees.

On Recent Funding since: Sep 29, 2026.

Signals

X account@tessl_io · created May 23, 2024 (2 years old) · 1,217 followers

Website registeredFeb 5, 2024 (2 years old)

About Tessl

Agents are powerful, but they can drift — misinterpreting requests, hallucinating APIs, or breaking existing features when adding new ones. Tessl integrates with most agents and uses spec-driven development to give agents (and you) a structured way to capture intent, run tests, and evolve codebases with fewer mistakes.

TIMELINE · MONEY RAISED

Tessl | 283 days from website to first raise on record

@tessl_io·Raised $125M in 1 sourced round·2 signals before the first raise

Money raised, round by round (amounts linked to their source). Pins are dated signals; hover the icons for dates.

Funding rounds

Date	Round	Amount	Lead	Source
Jun 3, 2026	Series A	undisclosed	—	fundraisingfox.com
Nov 14, 2024	Series A	$125M	IIndex Ventures	techcrunch.com

Timeline

May 23, 2024
X account created
February 5, 2024
Website created

Founders and team

GP
Guy Podjarny Founder

@guypod · LinkedIn · source: tessl.io
MC
Maurilio Cometto Head of Engineering
PD
Patrick Debois DevRel

Investors

Companies like Tessl

SSecondmind$16M · Nov 2023
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BBlitzy$200M Series A · May 2026
WWorkOS$100M Series B+ · Mar 2026
MMaxa$21M Series A · May 2024
CCausely$8.8M Seed · Jun 2023

Other companies backed by Index Ventures

FFlapping Airplanes$1B Series A · Oct 2026
DDuvo$32M Series A · Oct 2026
AAllara$30M Series A · Oct 2026
OOratomic$475M Series B+ · Oct 2026
VVesta$30M Series B+ · Oct 2026
HHone$60M Seed · Oct 2026

Index Ventures portfolio →

Sources and API

Every amount links to the page it came from. * Estimated from an accelerator's published standard deal, not a company-specific disclosure. How Recent Funding sources and verifies funding data. The same data as JSON: /api/v1/companies/tessl (get a free API key).