Top 12 Cobol Developer Skills to Put on Your Resume
In today's competitive job market, standing out as a COBOL developer takes more than a passing grasp of syntax. You need a resume that shows depth and balance: strong technical chops paired with people skills and a clear sense of how legacy systems keep the world humming. Employers scan fast. Show range, show currency, and make it easy to trust you with systems that simply cannot go down.
Cobol Developer Skills
1. COBOL
COBOL (Common Business-Oriented Language) powers finance, insurance, and government workloads that move staggering amounts of data. Readable, steady, and battle-tested, it remains the backbone for core systems where accuracy and throughput rule.
Why It's Important
COBOL sits at the heart of critical transaction processing worldwide. Mastery lets you keep these systems reliable, evolve them without breaking things, and deliver trusted results day after day.
How to Improve COBOL Skills
Grow fluency in the language and how it runs in real shops. Short punch list:
Master the basics: Data divisions, file handling, PERFORM nuances, intrinsic functions. Nail the fundamentals cold.
Learn modern COBOL: Enterprise COBOL features, inline PERFORM, compiler options, JSON/UTF-8 handling where available. GnuCOBOL concepts help round perspective.
Adopt best practices: Clear copybooks, consistent naming, tight scope for working-storage, and clean error handling. Small, testable paragraphs beat sprawling monoliths.
Use contemporary tools: Modern IDEs, source control, unit testing frameworks, code scanners. VS Code extensions and enterprise compilers make a real dent in productivity.
Practice constantly: Convert specs into programs, work on open examples, and refactor older code to modern idioms. Repetition hardens skill.
Keep learning, revisit your habits, and treat performance as a first-class feature.
How to Display COBOL Skills on Your Resume
2. JCL
JCL (Job Control Language) tells IBM mainframes exactly how to run batch jobs and set up execution environments. It’s the script behind the curtain—datasets, steps, utilities, condition codes, and more.
Why It's Important
Without JCL, COBOL batch doesn’t run. With good JCL, jobs are predictable, debuggable, and efficient—no surprises at 2 a.m.
How to Improve JCL Skills
Make job streams clear and resilient.
Name things well: Datasets, steps, and procs should explain themselves. Future you will thank you.
Tune space and allocation: Right-size SPACE, primary/secondary extents, and record formats to avoid waste and abends.
Modularize: Use PROCs and INCLUDEs to avoid duplication. One fix, many wins.
Control flow smartly: IF/THEN/ELSE, COND, and condition codes keep jobs self-driving and safer.
Harden error handling: Anticipate failures; write recovery and diagnostic steps so triage is quick.
Tune performance: Adjust CLASS, PRTY, and REGION based on workload profiles and SLAs.
Document intent: Inline comments where it matters. What, why, and side effects.
Stay current: New utilities and JCL features land regularly; apply them where they simplify life.
Clean JCL saves compute, cuts noise, and shortens recovery time.
How to Display JCL Skills on Your Resume
3. DB2
DB2 (IBM Db2) is an enterprise relational database engine built for scale and reliability. For COBOL applications, it’s the transactional heartbeat—queries, updates, and high-volume consistency.
Why It's Important
Db2 integrates cleanly with COBOL precompilers and transaction systems. You get fast, consistent data access with strong concurrency and tooling for heavy production workloads.
How to Improve DB2 Skills
Tune the database and the code that touches it.
Optimize SQL: Trim result sets, filter early, use set-based operations, and review access paths via EXPLAIN. Cursors only when needed.
Design indexes thoughtfully: Support primary access paths, avoid over-indexing, and watch maintenance costs.
Cluster and partition wisely: Align physical layout with access patterns to slash I/O.
Choose the right bind options: Isolation levels, RELEASE behavior, and currentdata settings impact concurrency and performance.
Tune buffer pools: Hot tables and indexes deserve memory. Measure, adjust, repeat.
Minimize locking pain: Keep transactions short, pick suitable lock sizes, and avoid unnecessary serialization.
Write efficient COBOL-DB2: Precompile options matter. Manage cursors tightly and commit in sensible batches.
Maintain relentlessly: RUNSTATS, REORG, and REBIND keep the optimizer honest and performance steady.
Measure first, change second. Then measure again.
How to Display DB2 Skills on Your Resume
4. CICS
CICS (Customer Information Control System) is the transaction server that makes online COBOL applications fast, safe, and scalable. High concurrency, tight response times, and rock-solid integrity.
Why It's Important
It’s where many mission-critical COBOL apps live. CICS keeps transactions quick, resources managed, and failures contained.
How to Improve CICS Skills
Design lean programs: Reduce chatty calls, handle errors predictably, and keep working storage trimmed.
Be resource-savvy: Reuse connections, tune DB2 access with indexes and parameter tweaks, and avoid hot locks.
Scale with intent: Exploit MRO and threadsafe programming for concurrency without chaos.
Stay current: New compiler and CICS TS versions bring measurable gains in optimization and security.
Monitor and tune: Use performance data to find hotspots—CPU, response times, storage—and fix what actually matters.
Harden security: Strong authentication, least-privilege authorization, encryption in motion and at rest where applicable.
Use the APIs: Integration points (web services, MQ, REST) extend reach without duct tape.
Automate delivery: CI/CD for CICS reduces drift and speeds safe releases.
Share knowledge: Pattern libraries and code examples prevent repeated mistakes across teams.
It all adds up to faster throughput and fewer late-night pages.
How to Display CICS Skills on Your Resume
5. VSAM
VSAM (Virtual Storage Access Method) provides indexed, relative, and sequential dataset access on IBM mainframes. It’s the file structure many COBOL apps rely on for speed and order.
Why It's Important
VSAM aligns with COBOL data processing patterns and can deliver high performance with strong control over record organization and integrity.
How to Improve VSAM Skills
Align access paths: Build keys and access patterns that match how programs read and update data. Minimize random I/O.
Tune buffering: Right-size buffers and CI/CA sizes. Let the I/O profile drive settings.
Consider RLS: Record Level Sharing can boost multi-user throughput when configured properly.
Use compression judiciously: Save space and sometimes I/O, but measure CPU trade-offs.
Reorganize routinely: After heavy churn, reorganize to restore order and performance.
Set SHAREOPTIONS wisely: Balance integrity with concurrency based on workload.
Write efficient COBOL logic: Limit START/STOP churn, use keyed reads and tight loops, and avoid unnecessary rewinds.
Great VSAM performance is mostly about predictable access and tidy files.
How to Display VSAM Skills on Your Resume
6. IMS DB/DC
IMS DB/DC combines a hierarchical database (IMS DB) with a high-performance transaction manager (IMS DC). COBOL programs issue DL/I calls to navigate segments and process transactions at serious scale.
Why It's Important
When low latency and bulletproof reliability matter, IMS delivers. Banking, insurance, and manufacturing depend on it for massive throughput.
How to Improve IMS DB/DC Skills
Design for access: Model segments and hierarchies to reflect real query paths. Keep hot paths shallow.
Use secondary indexes carefully: Add them for critical lookups, but watch insert/delete costs.
Code efficient DL/I: Choose the right calls (GU, GN, GHU, GHN), minimize needless I/O, and batch updates when safe.
Leverage features: Compression where it pays off, parallel processing for heavy batch, and buffering tuned to traffic.
Enable SQL access where appropriate: If your shop uses IMS Universal drivers or IMS SQL facilities, apply them thoughtfully. Otherwise, stick to well-structured DL/I patterns.
Monitor and tune: Use performance tools to spot bottlenecks—locking, path length, buffer shortages—and iterate.
Document segment usage: Clear maps of parent/child relationships make maintenance safer and faster.
Good hierarchy design plus disciplined calls yields outsized gains.
How to Display IMS DB/DC Skills on Your Resume
7. SQL
SQL (Structured Query Language) is the lingua franca for relational data. COBOL plus SQL brings powerful set-based processing to transactional programs and reports.
Why It's Important
COBOL applications often live or die by data access. SQL gives you concise, optimized ways to read and shape that data quickly and safely.
How to Improve SQL Skills
Lock down fundamentals: SELECT, INSERT, UPDATE, DELETE, constraints, and data types. Clean schemas enable clean code.
Master joins and subqueries: Inner, outer, semi-joins, window functions—build mental models to avoid Cartesian surprises.
Think in sets: Replace loops with set operations. Aggregations and analytic functions reduce code and increase speed.
Optimize deliberately: Understand indexing, statistics, and explain plans. Trim columns, filter early, and avoid scalar functions on indexed predicates.
Practice on real data: Tackle production-like scenarios. Tune queries until they’re boringly fast.
Know your precompiler: Embedded SQL in COBOL brings host variable nuances, cursor lifecycles, and error handling that deserve care.
Short SQL. Clear intent. Predictable performance.
How to Display SQL Skills on Your Resume
8. Mainframe
Mainframes process oceans of transactions with ironclad security and high availability. For COBOL developers, this is home base—batch, online, and everything in between.
Why It's Important
Large enterprises rely on mainframes for consistency, throughput, and compliance. COBOL runs best where reliability isn’t negotiable.
How to Improve Mainframe Skills
Optimize code paths: Reduce I/O, trim conversions, and keep hot loops tight. Measure, then shave cycles.
Modernize workflows: Use modern IDEs, code review, static analysis, and automated tests. Source control isn’t optional.
Exploit parallelism: Parallel job steps in JCL, Db2 parallel features, and CICS threadsafe programming outpace naive single streams.
Tune batch windows: Split big jobs, order steps for resource efficiency, and prioritize critical paths to hit SLAs.
Integrate with other languages: Pair COBOL with Java, Python, or REST endpoints where they shine. Pick the right tool for each part.
Optimize database access: Smart indexing and judicious commits keep throughput steady.
Monitor continuously: System and application metrics reveal contention early—fix the cause, not the symptom.
Adopt open tooling: Zowe, modern pipelines, and standardized APIs bring mainframe into today’s dev practices.
Performance is a discipline. Apply it end to end.
How to Display Mainframe Skills on Your Resume
9. TSO/ISPF
TSO gives interactive access to z/OS, while ISPF layers a productive, menu-driven interface on top. Editing, dataset management, browsing outputs—the daily toolkit.
Why It's Important
It’s the default cockpit for a lot of COBOL work. The faster you move here, the faster everything goes.
How to Improve TSO/ISPF Skills
Learn the shortcuts: ISPF editor line and primary commands save hours every week.
Customize your session: Colors, keymaps, and editor profiles that match your habits reduce friction.
Write ISPF macros: Automate repetitive edits and code scaffolding. Small scripts, big payoff.
Use file tailoring: Skeletons generate JCL and templates consistently—fewer typos, faster starts.
Search smarter: Cross-dataset searches and filters cut down hunting time.
Sharpen COBOL editing: Exploit the editor’s block operations, labels, and pattern matching to refactor safely.
Share utilities: Team-curated macros and panels standardize best practices.
Muscle memory here turns into speed everywhere.
How to Display TSO/ISPF Skills on Your Resume
10. PL/I
PL/I blends business data processing with scientific and systems features—pointers, strong string handling, and robust error facilities. A flexible complement to COBOL in mixed workloads.
Why It's Important
It opens doors beyond pure business logic—systems, numeric work, and hybrids—expanding what you can build without leaving the mainframe stack.
How to Improve PL/I Skills
Map the differences: Contrast PL/I data types, storage classes, and exception handling with your COBOL mental models.
Practice small: Write utilities that process files and strings. Incrementally add complexity.
Use structured features: Procedures, recursion (when appropriate), and modular design keep code tidy.
Read real code: Samples and legacy modules reveal idioms that docs rarely show.
Integrate wisely: Decide where PL/I adds value next to COBOL in your environment and split responsibilities cleanly.
Think versatility, not replacement. Use the right language for the job.
How to Display PL/I Skills on Your Resume
11. REXX
REXX is a friendly scripting language great for glue code, automation, and quick text or data wrangling. On z/OS, it’s perfect for tying tools together and smoothing rough edges.
Why It's Important
Automation wins. REXX lets you script repeatable tasks, prototype fast, and cut manual toil in TSO/ISPF and beyond.
How to Improve REXX Skills
Absorb the syntax: Simple variables, readable flow control, and strings as first-class citizens. Easy to start, powerful enough to keep.
Practice automation: Build scripts that generate JCL, parse logs, and orchestrate utilities.
Lean on built-ins: REXX functions handle strings and parsing elegantly—use them instead of reinventing wheels.
Integrate: Drive ISPF panels, call programs, and build small toolchains around daily developer tasks.
Study examples: Reading others’ scripts teaches idioms and shortcuts quickly.
Small scripts. Big time savings.
How to Display REXX Skills on Your Resume
12. Z/OS
z/OS is IBM’s 64-bit mainframe operating system built for security, throughput, and availability. It’s the platform where COBOL apps are compiled, executed, and governed at scale.
Why It's Important
For COBOL developers, z/OS provides the services—datasets, security, workload management, networking, and subsystems—that keep critical applications steady under heavy load.
How to Improve Z/OS Skills
Optimize COBOL on z/OS: Use compiler options, LE runtime tuning, and profiling to squeeze latency and CPU.
Modernize development: Embrace Git, pipelines, code review, and modern editors with z/OS integrations (including Zowe-based tooling).
Automate testing and deployment: Shift-left with unit tests and automated promotion to reduce drift and defects.
Strengthen observability: WLM metrics, SMF data, and subsystem monitors surface issues early—feed them into dashboards.
Keep current: New z/OS releases and middleware updates bring better security, performance, and diagnostics. Plan upgrades instead of reacting to them.
Operate like a modern platform team, even on the mainframe. The results compound.
How to Display Z/OS Skills on Your Resume
