Circle tech stack
Circle builds mostly with Ruby, JavaScript, TypeScript, Python. Its stack also includes Ruby on Rails, Figma, React.js, LangSmith. Ruby is named in 12 of the 33 job postings Circle published in the last 12 months (36%). Counted by Alion from the job postings of Circle, updated Oct 12, 2026.
What programming languages does Circle use?
Ruby is named in 36% of job postings at Circle, followed by JavaScript (33%), TypeScript (30%), Python (27%).
What frameworks and libraries does Circle use?
Ruby on Rails is named in 36% of job postings at Circle, followed by React.js (33%), Playwright (24%), React Native (24%).
Ruby on Rails
12 36%
React.js
11 33%
Playwright
8 24%
React Native
8 24%
Next.js
1 3%
Tailwind CSS
1 3%
What databases does Circle use?
MySQL is named in 6% of job postings at Circle, followed by PostgreSQL (6%).
MySQL
2 6%
PostgreSQL
2 6%
What cloud and platforms does Circle use?
Figma is named in 33% of job postings at Circle, followed by LangSmith (27%).
What developer tools does Circle use?
Braintrust is named in 27% of job postings at Circle, followed by Claude Code (6%), Cursor (6%), Lovable (6%).
What AI and ML technologies does Circle use?
LLM is named in 30% of job postings at Circle.
LLM
10 30%
Which engineering practices does Circle ask for?
CI/CD is named in 52% of job postings at Circle, followed by AI Agents (30%), A/B Testing (9%), Edge AI (3%).
What does each Circle team work with?
The technologies each team's postings require most often, with the number of postings that require them.
AI/ML
9 postingsIndustrial Engineering
8 postingsBackend
3 postingsHow does your stack fit Circle?
How much does Circle pay by technology?
Median stated pay of the postings that name each technology, against the median of all Circle postings with stated pay: $130k across 33 postings.
| Technology | Postings with pay | Median | vs company median |
|---|---|---|---|
| Ruby | 12 | $170k | +31% |
| Ruby on Rails | 12 | $170k | +31% |
| JavaScript | 11 | $130k | 0% |
| React.js | 11 | $130k | 0% |
| Figma | 11 | $120k | −8% |
| LLM | 10 | $170k | +31% |
| TypeScript | 10 | $130k | 0% |
| LangSmith | 9 | $170k | +31% |
| Python | 9 | $170k | +31% |
| Playwright | 8 | $130k | 0% |
How modern is the Circle stack?
Circle scores 82 out of 100 (Cutting-edge). The score averages how current each technology in the stack is and adds weight for AI adoption. AI technologies in the stack: 1; legacy ones: 0.
Companies with a stack like Circle
Questions about the Circle tech stack
What programming languages does Circle use?
The languages named in Circle job postings are Ruby (36%), JavaScript (33%), TypeScript (30%), Python (27%), as a share of the 33 postings of the last 12 months.
Does Circle use Ruby on Rails?
Yes. Ruby on Rails is named in 12 of 33 job postings (36%) and required in 12 of them.
What cloud and platforms does Circle use?
The cloud and platforms named in Circle job postings are Figma (11), LangSmith (9) (postings in brackets).
What skills do you need for a AI/ML job at Circle?
AI/ML postings at Circle most often require Braintrust (9), LLM (9), LangSmith (9), Python (9), out of 9 postings in the last 12 months.
Is the Circle tech stack changing?
No new technology has appeared in Circle job postings in the last six months.
How modern is the Circle tech stack?
Circle scores 82 out of 100 (Cutting-edge). The score averages how current each technology in the stack is and adds weight for AI adoption. AI technologies in the stack: 1; legacy ones: 0.
How does Alion know the Circle tech stack?
Alion reads every job posting Circle publishes and tags the technologies each one names. The figures on this page count the 33 postings of the last 12 months and were updated on Oct 12, 2026.
Method and citation
Alion reads every job posting the company publishes and tags the technologies each one names. Shares count the postings of the last 12 months, open and closed; the company's own products are counted apart. How we count
Alion, "Circle tech stack: 25 technologies from 33 job postings", as of Oct 12, 2026. https://alion.io/company/circle-so/technologies