RedLens — SQL IDE & MCP for Amazon Redshift

A Redshift-native SQL IDE for VS Code, with an MCP server built in.

Connect four ways, browse your catalog, run SQL, read plans with warehouse-aware warnings — and hand the same connections to Copilot or Claude without wiring up a thing. Built for data engineers, analytics engineers and anyone who lives in Redshift and would rather not live in a browser tab.

What it looks like

The editor and the catalog — completion from your live schema, and results you can filter, chart, transpose and export without leaving the tab.

The Table Optimization Advisor (Pro) — distribution skew, unsorted blocks, stale statistics and AWS's own recommendations, each with the SQL that fixes it.

Plans with warehouse-aware warnings — the parts of a plan that cost you money, named.

PII-safe mode — columns that look like personal data are masked until you ask, so a screen-share or a pairing session is not an incident.

Datashares, users, roles and policies in the tree — and, per object, who can do what. Column-level grants and RBAC roles included, which is where the other clients stop.

What the warehouse is costing you (Pro) — CloudWatch metrics with the RPU cost of the window you are looking at.

Open source

This extension is open source under the MIT licence. Everything described below as free is in this repository — you can read it, build it, fork it, and use it commercially without asking anyone.

RedLens is open core. There is a second, paid extension — RedLens Pro — that adds warehouse-specific advice, the Redshift console, AI grounded in your schema and governance administration. It is closed source and it is a separate install.

Three things worth saying plainly, because open core has a reputation and it was earned:

• The free tier is the whole free product, not a demo. Connecting, browsing, editing, running, reading results and the embedded MCP server are complete and stay that way.
• Nothing that ships free ever moves to Pro. New Pro features are new features, never features you already had.
• Where the line falls is a file you can read: src/licensing/tiers.ts. It lives in the open repository on purpose. You should not have to install anything to find out what you are getting.

Every safety feature is free and always will be — read-only mode, the production safeguard, transaction control and PII-safe masking. Charging for not leaking PII is not a position worth defending.

Free and Pro

RedLens installs free, and Free is a complete daily loop — not a demo.

Unlimited connections of all four kinds, the schema explorer, the SQL editor with metadata-driven autocomplete and linting, the entire result grid, query history, saved queries, SQL notebooks, the EXPLAIN visualizer, the visual query builder, CSV import, the governance tree, sessions and locks, the basic read-only MCP tools, and every safety feature. Connections are never counted. History is never capped.

Pro is what saves money, prevents incidents and governs.

Every install starts with 14 days of full Pro. No credit card. No account. No sign-up. The trial begins on first activation. When it ends nothing breaks — the Pro features lock, everything else keeps working forever.

Our promise: nothing that ships Free ever moves to Pro. New Pro features are new features, never features you already had.

Price

• Pro — $99 per person / year. → Buy RedLens Pro
• Team — $79 per seat / year, minimum 5 seats. → Buy Team seats
• Enterprise — on request.

Licences are bought outside VS Code and outside the Visual Studio Marketplace. You buy on the RedLens site, receive the key by email, and paste it into VS Code with RedLens: Manage Licence. There is no account to create and no RedLens server to talk to: keys are verified offline against a public key embedded in the extension.

Cancelling is a button, in the customer portal — no email to us, no notice period, and you keep Pro until the end of the term you paid for. Invoices, payment method, seats and machine activations live there too.

Two commitments that come with paying:

• Refunds: 14 days, no questions asked — on a purchase or a renewal.
• After twelve months of paying, the last version you paid for is yours to keep, permanently, Pro features included. You stop getting upgrades and support, not the software.

Why RedLens

Redshift-native, not Postgres-with-a-hat. No driver to hunt down, no second extension to install. Distribution and sort key advice, skew, WLM queues, RPU cost, decoded COPY errors, datashares, RLS and masking, effective permissions — the things a Redshift warehouse actually breaks on.

The MCP server is built in. Your connections are exposed to GitHub Copilot, Claude and any MCP client inside VS Code, with engine-level read-only enforcement — the guarantee lives in the query engine, not in a prompt. Zero configuration; installing RedLens is the setup.

PII is masked before results reach the model. With PII-safe mode on, masking happens on the way out of the engine, so a language model or MCP client never sees the raw values.

Nothing leaves your machine. No account, no telemetry backend, no licence server. AWS credentials stay in ~/.aws or VS Code Secret Storage. RedLens works inside a private VPC with no egress.

Connect four ways

Profiles are saved; passwords and keys live in VS Code Secret Storage. For cross-user query monitoring on a real cluster you will also want the SYS:MONITOR role granted to the connecting user.

Start with Demo mode. No credentials, no cluster, no AWS account — a sample warehouse loads instantly and every Free feature works against it.

What you get

Schema explorer

A lazy tree of schemas → tables and views → columns, including external (Spectrum) schemas. One-click preview of a table's first rows, object scripting, a schema diagram, search across objects and find-usages.

SQL editor

Run a selection or a whole file with Ctrl+Enter, cancel a running query, control transactions explicitly. Autocomplete is driven by live catalog metadata — real schemas, tables and columns — plus Redshift keywords and functions. Linting, snippets, saved queries and a searchable history come with it.

The result grid — all of it, free

Sort, filter, chart, heatmap, transpose, group, pin a baseline and diff two runs against each other, edit rows in place and commit, paste rows in, export. There is no "premium grid".

SQL notebooks and the visual query builder

Notebook cells for narrative analysis; a builder for when you would rather click than type.

EXPLAIN visualizer

The plan as a tree, with warehouse-aware warnings — DS_BCAST / DS_DIST broadcasts, oversized scans — and concrete DISTKEY/SORTKEY advice. EXPLAIN ANALYZE too.

Embedded MCP server

Read-only tools registered automatically inside VS Code: list databases, schemas, tables and columns, run a read-only query, explain a query. Read-only is enforced by the engine. Point Copilot or Claude at your warehouse without writing a config file.

Safety, always free

Read-only mode. A production safeguard that makes you confirm before a write against a cluster you have flagged as production. PII-safe masking. These are free forever and, by design, cannot be moved to Pro.

Performance Dashboard Pro

CloudWatch infrastructure metrics next to query activity, and the RPU cost of the window you are looking at. Refreshes only when you ask it to — metric calls are billed per request, and a panel that polls on a timer is a bill you did not agree to.

Table Advisor Pro

Distribution and sort key advice, skew, stale statistics — plus the AWS Advisor recommendations with the SQL they recommend.

Query & Load Monitoring Pro

WLM queueing, cost per query, and COPY errors decoded into something you can act on.

Cluster view Pro

The Redshift console's configuration in the sidebar: parameters, network, snapshots, maintenance, logging, scheduled actions, limits, events and reserved nodes. Read-only, and Properties is free. Parameters that differ from the engine default are listed first — the console does not do that. RedLens never mutates your cluster: for actions it generates the aws CLI for you to review and run, and it will generate the minimal read-only IAM policy it needs, explaining what breaks without each statement.

Compare Schemas · Compare Table Data · Schedule Query Pro

Diff two schemas and get the migration DDL. Row-level diff between two tables. Generate the EventBridge Scheduler CLI to run a query on a schedule.

S3 UNLOAD / COPY wizards Pro

Guided UNLOAD with format, compression and partitioning; guided COPY with the IAM role and the error handling COPY actually needs. Generated for review — never executed behind your back.

Governance Pro

Effective Access: why a user can do something, with transitive role resolution and the exact path that grants it. RLS and masking policies. Generated user, role and datashare SQL, always for review, never executed.

AI Pro

Natural language to SQL, explain a plan, optimize a query, fix the last error, describe an object — all grounded in your live catalog — plus the @redlens chat participant. AI runs on your VS Code language model subscription; RedLens ships no model and no API key.

Requirements

• VS Code — see the Version field on this page for the minimum release.
• A workspace you trust: RedLens holds warehouse credentials and can open SSH tunnels, so it does not run in Restricted Mode.
• For Data API connections: AWS credentials in ~/.aws with permission to call the Redshift Data API. RedLens can generate the minimal read-only IAM policy for you.
• For direct connections: network reachability to the cluster (optionally through an SSH bastion).
• For Demo mode: nothing.
• AI features use the VS Code language model API and therefore require an active Copilot (or equivalent) subscription. RedLens does not resell model access.

RedLens starts an embedded MCP server as a separate local process so MCP clients inside VS Code can reach your connections. It communicates over stdio, is registered only within VS Code, and stops with the extension.

Security and privacy

• No RedLens server. No account, no sign-in, no callback. The extension never phones home to us.
• Credentials stay local. IAM credentials are read from ~/.aws; passwords, SSH keys and licence keys live in VS Code Secret Storage.
• Licence keys verify offline against an Ed25519 public key embedded in the extension. RedLens works in an air-gapped VPC with no egress.
• Read-only is enforced in the engine, not in a prompt — that is what makes exposing your warehouse to a language model defensible.
• PII-safe mode masks values before they leave the engine, so MCP clients and language models never receive the raw data.
• Your SQL, schema names, endpoints, results and errors are never transmitted to RedLens.

Telemetry is off by default. If you turn it on, RedLens records only that the extension activated and which of its own commands ran — never SQL, object names, endpoints, database names, AWS account identifiers, error messages, row counts or results. VS Code's own telemetry setting always wins: if that is off, RedLens sends nothing regardless.

FAQ

Support

• Bugs and feature requests: the public issue tracker linked under Resources on this page.
• Security reports: see SECURITY.md. Please do not open a public issue for a security problem.
• Billing and licensing: the contact on your purchase receipt.

Licence

This extension is open source under the MIT licence. RedLens Pro is a separate, commercial extension with its own end-user licence agreement.

Amazon Redshift, Amazon S3, AWS and CloudWatch are trademarks of Amazon.com, Inc. or its affiliates. RedLens is an independent product and is not affiliated with, endorsed by, or sponsored by Amazon Web Services.