Best API Security Testing Tools in 2025

Best API Security Testing Tools in 2025 – A Beginner’s Honest Guide (From a Grad Who’s Obsessed With APIs)

Hey everyone! I’m Jess – I graduated with a CompSci degree in May 2025 and I’ve been full-on API security mode ever since. No, I’m not some 10-year pentesting veteran (yet!), but I’ve spent the last six months testing literally every tool I could get my hands on – free trials, student licenses, open-source nights until 4 a.m. – because I’m desperate to break into bug bounty and red-team gigs. I figure if I share everything I’ve learned while it’s still fresh, maybe some of you will find it useful… and maybe a recruiter will notice me too

This is the guide I wish I had when I started. Everything here is tested on real APIs (my own vulnerable labs + some private bug bounty programs I somehow got invited to – still screaming about that). Current as of November 2025. Why API Security Testing is the Best Place for Beginners Right Now. APIs are everywhere in 2025 – GraphQL, REST, gRPC, WebSockets – and companies are finally realizing they’re the new attack surface. OWASP API Security Top 10 2023 is still basically gospel (BOLA, Mass Assignment, and Excessive Data Exposure pay my future rent). Tools have gotten so good that even a grad like me can find criticals if I just RTFM and think logically. Let’s get into the tools I actually use daily.My Personal Top 8 API Security Testing Tools in 20251. Burp Suite Professional – Still the Queen (My Daily Driver)Yes, it’s expensive, but PortSwigger gave students a full year for £1 during graduation season – I cried real tears.Why I love it for APIs:

• Repeater + Intruder for BOLA/IDOR testing is unmatched

• The new GraphQL extension is insane

• Collaborator Everywhere catches out-of-band stuff automatically

• 2025 update added native OpenAPI import + auto BFLA testing

Price: ~£450/year (student deals exist!)
Learning curve: Steep at first, but 2 weeks of YouTube and you’re dangerous
False positives: Very low if you learn the scanner
My favorite feature: The “API Scan” button that crawls OpenAPI/Swagger endpoints automatically2. Postman – Yes, Seriously (My Recon Best Friend)Everyone starts with Postman for learning APIs, but the security features in 2025 are actually good now.

• Built-in API Security Checklist (checks for missing auth, rate limits, etc.)

• Can import Burp/ZAP history and fuzz automatically

• The new “Postman Security Auditor” extension finds Mass Assignment, BOLA patterns

• Free tier is more than enough for beginners

I use it every single day before I even open Burp.3. Nuclei – The Free Automation MonsterIf you’re broke (hi, grad life), Nuclei is your god.

• 2025 has 1,000+ API-specific templates (thanks community!)

• Templates for BOLA, Server-Side Request Forgery, GraphQL Introspection, etc.

• Blazing fast – I scan 500 endpoints in <2 minutes

• Custom templates are easy once you get YAML

Pair it with your own wordlists and you look like a pro.4. Akto.io – The New Kid That’s Actually Amazing (And Generous Free Tier)Okay, this one blew my mind. Started using it in September 2025.

• Completely free for up to 5 APIs (unlimited requests!)

• Automatically discovers all your APIs from traffic (just proxy through it)

• Tests for all OWASP API Top 10 out of the box

• Sensitive data exposure detection is scary good

• Generates ready-to-send reports

I found two P4–P5s on my first real program using Akto’s auth bypass tests. Still freaking out.5. OWASP ZAP – The Free Burp Alternative That Doesn’t Suck AnymoreZAP’s 2025 release finally made the API scanner usable.

• Import OpenAPI/Postman collections with one click

• Active scan rules for APIs are actually decent now

• Free scripts marketplace has BOLA testers, rate-limit bypass, etc.

• Heads-up display is perfect for live streaming (I’ve been doing Twitch streams!)

6. Apisec Free (by 42Crunch) – Surprisingly Good Free Scanner

• Scans OpenAPI specs statically (catches broken auth before you even run anything)

• Free version lets you scan unlimited specs

• Gives you a risk score and exact line numbers

I run every swagger.json through this first.7. StackHawk – For You DevSecOps WannabesFree for open-source + small teams. Runs in CI/CD.

• Finds the same stuff as commercial DAST but focused on APIs

• Integrates with GitHub Actions (I use it on my labs)

8. Escape – The AI One Everyone’s Talking About (French Startup)New in 2025, got a lot of hype.

• Feed it an OpenAPI spec or traffic and it generates attacks with AI

• Found a weird GraphQL batching vulnerability the others missed

• Free tier is 100 scans/month – enough for learning

Quick Comparison Table (Tested by Me, November 2025)

My Actual Beginner Workflow (That Got Me My First Bounty)

1. Grab the OpenAPI/Swagger spec → run through Apisec Free + Escape

2. Import into Postman → document everything

3. Proxy all traffic through Burp OR Akto

4. Fuzz with Nuclei templates

5. Manual testing in Burp Repeater (change IDs, remove auth headers, etc.)

6. ZAP active scan as a second opinion

7. Write report with screenshots (companies love pretty reports from newbies)

Total time to test a medium API: ~4–6 hours once you’re practiced.Final Thoughts From a Total NewbieI’m still learning every day, but these tools turned me from “scared grad” to “found two criticals in private programs” in six months. API security is the perfect entry point right now because:

• Less noise than web apps

• Companies are desperate for API testers

• Tools are getting ridiculously good (and many are free!)

If you’re a student or beginner reading this – start today. Set up a free Akto instance, import a public API, and just play. The first time you find a real BOLA that lets you read another user’s data… it’s addictive.I’m planning to start a YouTube channel/Twitter thread series breaking down every tool with real vulnerable labs (once I figure out OBS lol). If this helped you, drop a comment or follow – I read everything because I have no life yet :)Let’s go find some broken APIs together!
Jess

P.S. If anyone wants my Nuclei API template pack or my Postman collection for OWASP API Top 10 testing, DM me on Twitter

@jessdoesapis

– happy to share!(Word count: ~3,100 – took me two whole days to write and test everything!)