scan
Scan is a lightweight Go library that maps SQL query results directly into Go structs, slices, and primitive types without boilerplate. It integrates with the standard library's database/sql package and supports nested structs, custom column mapping, and strict scanning modes.
Key facts
Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.
| Field | Value |
|---|---|
| Repository | blockloop/scan |
| Owner | blockloop |
| Primary language | Go |
| License | MIT — OSI-approved |
| Stars | 614 |
| Forks | 33 |
| Open issues | 1 |
| Latest release | v2.5.0 (2023-08-31) |
| Last updated | 2026-07-07 |
| Source | https://github.com/blockloop/scan |
What scan is
A minimal Go scanning layer for database/sql that uses reflection to populate struct fields from SQL rows, featuring field caching via sync.Map for performance, db tag support, and both lenient and strict scanning modes. No ORM overhead; works with any SQL query builder.
Get the scan source
Clone the repository and explore it locally.
git clone https://github.com/blockloop/scan.gitcd scan# follow the project's README for install & configurationNeed it deployed, integrated, or customized instead? DEV.co ships production installs.
Best use cases
Implementation considerations
- Struct field visibility: only exported (uppercase) fields are scanned; private fields are silently ignored.
- Column naming: by default uses title-case conversion; must set custom ColumnsMapper/ScannerMapper for non-standard naming or use db tags for explicit mapping.
- Nested struct support: flatten joins and map via db tags (e.g., db:"company.name"); no automatic JOIN hydration.
- Error handling: scan errors typically occur during reflection or row scanning; must inspect row.Err() separately.
- Type mismatches: incompatible types between column and struct field cause runtime panics; use strict mode and db tags to reduce risk.
When to avoid it — and what to weigh
- Complex relational mapping needed — If you require automatic handling of foreign keys, polymorphic types, or complex join hydration, use sqlc, gorm, or sqlx instead; scan does basic field population only.
- Active schema evolution required — Projects with frequent breaking schema changes benefit more from generated code (sqlc) or runtime type introspection layers; scan's tag-based mapping offers less flexibility.
- No Go expertise available — Scan requires understanding of Go struct tags, reflection, and database/sql semantics; teams without Go experience should evaluate higher-level frameworks.
- Future feature demands uncertain — Maintainer has stated the project is 'complete' and dormant since ~2021; if you anticipate needing new features, fork or choose an actively maintained alternative.
License & commercial use
MIT License permits commercial and private use, modification, and distribution with no royalty or attribution obligation, only requiring license and copyright notice preservation.
MIT is a permissive OSI-approved license suitable for proprietary commercial products. No restrictions on closed-source use or sublicensing. Recommended to include license file in distribution.
DEV.co evaluation signals
Editorial assessment — not user reviews. Directional, with an explicit confidence level.
| Signal | Assessment |
|---|---|
| Maintenance | Stale |
| Documentation | Adequate |
| License clarity | Clear |
| Deployment complexity | Low |
| DEV.co fit | Good |
| Assessment confidence | High |
No specific security vulnerabilities noted in available data. As a reflection-based scanning library, it does not execute arbitrary SQL or deserialize untrusted data. Use prepared statements (via database/sql) to prevent SQL injection; scan's role is result mapping only. Field tag parsing is not a known attack vector.
Alternatives to consider
sqlc
Type-safe, generated scanning code from SQL schema; eliminates reflection and field tag overhead but requires schema definition upfront and code generation step.
sqlx
More feature-rich scanning library with automatic tag support, nested struct mapping, and transactions; heavier than scan but actively maintained.
gorm
Full ORM with relationship handling, query builder, migrations, and hooks; substantially heavier but handles complex schemas and rapid iteration.
Build on scan with DEV.co software developers
Our Go development experts can assess whether Scan fits your schema and workload, help you avoid common pitfalls with reflection and field mapping, and recommend alternatives if a more feature-rich solution is needed.
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scan FAQ
Is scan actively maintained?
Does scan support nested structs and joins?
What is the performance impact compared to manual row.Scan()?
Can I use scan with connection pooling or transactions?
Software developers & web developers for hire
Adopting scan is usually one piece of a larger software development effort. As a software development agency, DEV.co provides software development services and web development expertise — pairing senior software developers and web developers with your team to design, build, and operate open-source databases software in production.
Need help evaluating or integrating Scan?
Our Go development experts can assess whether Scan fits your schema and workload, help you avoid common pitfalls with reflection and field mapping, and recommend alternatives if a more feature-rich solution is needed.