regex101: JWT pattern

Pro

ethe literal e (101₁₀ / 145₈ / 65₁₆) (case sensitive)

Character Class[yw]

ythe literal y (121₁₀ / 171₈ / 79₁₆) (case sensitive)

wthe literal w (119₁₀ / 167₈ / 77₁₆) (case sensitive)

Character Class[A-Za-z0-9-_]+

+matches at least one character from the set below:

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Non-Capturing Group(?:e[yw][A-Za-z0-9-_]+)?

?repeats the group contents below at most once:

ethe literal e (101₁₀ / 145₈ / 65₁₆) (case sensitive)

Character Class[yw]

ythe literal y (121₁₀ / 171₈ / 79₁₆) (case sensitive)

wthe literal w (119₁₀ / 167₈ / 77₁₆) (case sensitive)

Character Class[A-Za-z0-9-_]+

+matches at least one character from the set below:

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[A-Za-z0-9-_]{2,}

{2,}matches at least 2 characters from the set below:

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

Non-Capturing Group(?:(?:\.[A-Za-z0-9-_]{2,}){2})?

?repeats the group contents below at most once:

Non-Capturing Group(?:\.[A-Za-z0-9-_]{2,}){2}

{2}repeats the group contents below exactly 2 times:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[A-Za-z0-9-_]{2,}

{2,}matches at least 2 characters from the set below:

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

26 tokens

Regular Expression

e[yw][A-Za-z0-9-_]+\.(?:e[yw][A-Za-z0-9-_]+)?\.[A-Za-z0-9-_]{2,}(?:(?:\.[A-Za-z0-9-_]{2,}){2})?

New

JWT pattern

- handles both JWS (3 segments) and JWE (5 segments)
  - remove the ending `(?:(?:...` to handle JWS only
- segments 1+2 are expected tp start with `e[yw]`, an encoded start of JSON object `{"` or `{\n`
  - remove/extend it to match used token structure
  - or make it even more restrictive `(ey[IJ]|ewo)` to match encoded `{"\w` or `{\n"`
- payload (2nd segment) may be empty
- both header (1st segment) and payload are expected to start with `eyJ`, a base64 encoded start of JSON object `{"`
- accepts only proper Base64url encoding (RFC 4648) without Base64 padding `=`
- test it at https://regex101.com/r/V99DS0

eyJhbGciOiJkaXIiLCJlbmMiOiJBMjU2Q0JDLUhTNTEyIiwia2lkIjoicEw1NGdLalBHWElQVWw3eGlGN3B5MExJY3IxNkhPVlZnTXBtWjZqZmFUcUppb1h6M0FSM21EaWpTdXFxNnNvSTBoM1BaNzdMdDUzRjVUbVVPRW5KRGcifQ..LxFPkpn8Gu8vFuXDtOKA1A.DkMr_qOgv6zdyFiZGnz01wnFfLLmoMpRA-L3EbmgOGv21E-yU8ks7C_MSwA6E8KpXAB7XHeejJQWvs5ZrxDM2G8_t_BIJ6DUFXvLvLOzdo0hceeCCtujAgMPsjxW0RQFHkrA2VOlpuF7vVgJXPby19t0_QBWIaZnpfnAYzDJ98UpO1WbNxqGfdpbNG6RETpH.w1H3V7eGynuOi2qJUooceTCvoC4P5sT7bQRqbLZuyR0

Substitution

JWT pattern

- handles both JWS (3 segments) and JWE (5 segments)
  - remove the ending `(?:(?:...` to handle JWS only
- segments 1+2 are expected tp start with `e[yw]`, an encoded start of JSON object `{"` or `{\n`
  - remove/extend it to match used token structure
  - or make it even more restrictive `(ey[IJ]|ewo)` to match encoded `{"\w` or `{\n"`
- payload (2nd segment) may be empty
- both header (1st segment) and payload are expected to start with `eyJ`, a base64 encoded start of JSON object `{"`
- accepts only proper Base64url encoding (RFC 4648) without Base64 padding `=`
- test it at https://regex101.com/r/V99DS0

eyJhbGciOiJkaXIiLCJlbmMiOiJBMjU2Q0JDLUhTNTEyIiwia2lkIjoicEw1NGdLalBHWElQVWw3eGlGN3B5MExJY3IxNkhPVlZnTXBtWjZqZmFUcUppb1h6M0FSM21EaWpTdXFxNnNvSTBoM1BaNzdMdDUzRjVUbVVPRW5KRGcifQ..LxFPkpn8Gu8vFuXDtOKA1A.DkMr_qOgv6zdyFiZGnz01wnFfLLmoMpRA-L3EbmgOGv21E-yU8ks7C_MSwA6E8KpXAB7XHeejJQWvs5ZrxDM2G8_t_BIJ6DUFXvLvLOzdo0hceeCCtujAgMPsjxW0RQFHkrA2VOlpuF7vVgJXPby19t0_QBWIaZnpfnAYzDJ98UpO1WbNxqGfdpbNG6RETpH.w1H3V7eGynuOi2qJUooceTCvoC4P5sT7bQRqbLZuyR0